Tests With Codes

G - TESTS W/CODES - 4.6L Article Text 1995 Cadillac Concours For Ace Mechanics 123 Main Street San Diego Ca 92126 Copyright © 1997 Mitchell International Friday, November 28, 2003 07:15PM

ARTICLE BEGINNING

1995 ENGINE PERFORMANCE General Motors Corp. Self-Diagnostics - 4.6L Cadillac;

Concours

INTRODUCTION

If no trouble codes were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed with self-diagnostics. If no fault codes or only pass codes are present after entering self-diagnostics, proceed to H - TESTS W/O CODES article in the ENGINE PERFORMANCE section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.). SELF-DIAGNOSTIC SYSTEM

NOTE:

Electronic Control Module (ECM) and Powertrain Control Module (PCM) are the same system. Terms are often used interchangeably.

Self-diagnostic system consists of 6 components. These components are Powertrain Control Module (PCM), Instrument Panel Cluster (IPC) options, A/C Programmer (ACP) options, Supplemental Inflatable Restraint (SIR) system, Traction Control system (TCS) and Road Sensing Suspension (RSS) system options. In addition to monitoring a particular set of sensors and switches, PCM maintains continuous communication with each system component. Should a component exceed pre-programmed limits, PCM will recognize a malfunction and may act to control malfunctioning component. To control a particular component, PCM rapidly switches an internal circuit between zero and 5 volts, converting programmed control information into series of pulses that represents coded serial data messages. These messages are transmitted to malfunctioning component, which interprets information and responds accordingly. As a result, an alphanumeric code, known as a trouble code, is often set in PCM memory. This trouble code identifies malfunctioning component and can be accessed by a service technician as an aid to diagnostic procedures. All trouble codes are displayed on Driver Information Center (DIC) panel. In addition to monitoring self-diagnostic system and displaying trouble codes, PCM can be programmed by service technician to perform specific diagnostic tests on individual components and systems. Results of these tests are displayed on DIC. This article covers accessing PCM trouble codes and programming self-diagnostic system to perform specific diagnostic tests on system components.

ENTERING SELF-DIAGNOSTICS

1) Turn ignition on. Simultaneously push OFF and WARMER buttons on Climate Control Center (CCC). Continue pushing OFF and WARMER buttons until segment check appears (about 3 seconds) on Instrument Panel Control (IPC). NOTE:

Failure of any segment to glow may result in inaccurate test results. Replace any inoperative segment display before proceeding with self-diagnostic process.

2) When segment check appears (all segments glow), system has entered self-diagnostic mode. Release both buttons. Driver Information Center (DIC) will display diagnostic codes. Diagnostic code level displays PCM codes first, followed by IPC, ACP, SIR, TCS and RSS codes (if so prompted). 3) To proceed to desired level, press and release CCC HI (fan up) button for "yes" or LO (fan down) button for "no". Depress LO button to go to next test level (i.e., IPC?, ACP?, SIR?, TCS? or RSS?) or depress OFF button to return to next selection in previous test level. 4) To exit diagnostics, press AUTO or DEFOG button on IPC. System will go back to normal vehicle operation. DISPLAYING TROUBLE CODES

1) Trouble codes appear in ascending (3-digit) numerical order and are prefixed by "P" (PCM), "I" (IPC), "A" (ACP), "R" (SIR), "T" (TCS) or "S" (RSS). A final digit of either a "C" (current) or "H" (history)" will also be indicated on every code. Diagnostic code level displays PCM codes first, followed by IPC, ACP, SIR, TCS or RSS codes (if so prompted). 2) For complete list of available PCM trouble codes, see PCM TROUBLE CODES table. If no codes are present for a system, a "NO X CODE" message (with X being system, i.e. "P", "I", etc.) will be displayed. If communication line to a component is not operating, a "NO X DATA" message will be displayed, indicating that IPC could not communicate with that system. 3) To continue with system diagnostics, see SERVICE MODE OPERATION. To exit from SERVICE MODE and go back to normal vehicle operation, depress AUTO or DEFOG button on CCC. PCM TROUBLE CODES TABLE ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

Code

Test Condition

P012 (1) ................. No 4X Signal From Ignition Control Module P013 (1) W/CODES .............................. Rear Oxygen Sensor123 Not Ace Mechanics MainReady Street San Diego Ca 9212 G - TESTS - 4.6LArticle Text (p. 2)1995 Cadillac ConcoursFor

P014 P015 P016 P017 P019 P020 P021 P022 P023 P024 P025 P026 P027 P028 P029 P030 P031 P032 P033 P034 P035 P036 P037 P038 P039 P040 P041 P042 P043 P044 P045 P046 P047 P048 P051 P052 P053 P055 P056 P057 P058 P059 P060 P061 P062 P063 P064 P065

(1) (1) (2) (1) (2) (2) (1) (1) (1) (1) (2) (1) (1) (1) (1) (1) (1) (1) (2) (1) (3) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (2) (1) (1) (3) (3) (1) (1) (2) (8) (2) (3) (3) (3) (3) (3) (3)

................ Shorted Engine Coolant Temp. Sensor Signal ................... Open Engine Coolant Temp. Sensor Signal (4) (5) (6) (7) ........... Alternator Voltage Out Of Range ............................. Front Oxygen Sensor Not Ready ................................. Shorted Fuel Pump Circuit .................................... Open Fuel Pump Circuit (4) ............................. Shorted TP Sensor Circuit (4) ................................ Open TP Sensor Circuit .......................... Ignition Control Circuit Problem (4) .................. Vehicle Speed Sensor Circuit Problem .................................. 24X Reference Signal Low (6) ............................. Shorted TP Sensor Circuit (6) ................................ Open TP Sensor Circuit ................. Transaxle Pressure Switch/Circuit Problem ...................... Transaxle Shift Solenoid "B" Problem ................. Idle Speed Control (ISC) RPM Out Of Range (7) ............................ Shorted MAP Sensor Circuit (7) ............................... Open MAP Sensor Circuit (5) ............... Extended Travel Brake Sw. Input Circuit (7) ............................ MAP Sensor Signal Too High ...................... Ignition Ground Voltage Out Of Range (6) ...................... EGR Pintle Position Out Of Range .................... Shorted Intake Air Temp. Sensor Signal ....................... Open Intake Air Temp. Sensor Signal (4) ...... Torque Converter Clutch (TCC) Engagement Problem ....................... Power Steering Pressure Switch Open ................. No Cam Sensor Signal From Ignition Module ........................... Front Oxygen Sensor Lean Signal ........................... Front Oxygen Sensor Rich Signal ............................ Rear Oxygen Sensor Lean Signal ............................ Rear Oxygen Sensor Rich Signal ...................... Front-To-Rear Bank Fueling Imbalance ...................................... PCM/BCM Data Problem (7) ...................................... EGR System Fault ................................................ PROM Error ............................... PCM Keep Alive Memory Reset ........ 4X Reference Signal Interrupt From Ignition Module .................................... TP Sensor Out Of Range .............. Transaxle Input Speed Sensor Circuit Problem .............. Shorted Transaxle Temperature Sensor Circuit ........................... PASS-Key(R) Fuel Enable Problem ................. Open Transaxle Temperature Sensor Circuit (5) ............... Cruise Control - Transaxle Not In Drive (5) ................ Cruise Control - Vent Solenoid Problem (5) .............. Cruise Control - Vacuum Solenoid Problem (5) .................. Vehicle Speed & Set Speed Difference (5) ......................... Vehicle Acceleration Too High (5) .......... Cruise Control Servo Position Sensor FailureG - TESTS W/CO

P066 P067 P068 P069 P070 P071 P073 P074 P075 P076 P080 P081 P083 P085 P086 P088 P089 P090 P091 P092 P093 P094 P095 P096 P097 P099 P102 P103 P105 P106 P107 P108 P109 P110 P112 P117 P119 P131 P132 P137 (1) (2) (3) (4) (5) (6) (7)

(3) (5) .................. Cruise Control - Engine RPM Too High (3) (5) .................. Cruise Control Switch Signal Shorted (3) (5) ............ Cruise Control Servo Position Out Of Range (3) (5) ............... Traction Control Active While In Cruise (3) ............................. Intermittent TP Sensor Signal (3) ............................ Intermittent MAP Sensor Signal (3) ........... Intermittent Engine Coolant Temp. Sensor Signal (3) ............... Intermittent Intake Air Temp. Sensor Signal (3) (4) ........... Vehicle Speed Sensor (VSS) Signal Interrupt (1) ............... Transaxle Pressure Control Solenoid Circuit (1) ......................... TP Sensor/Idle Learn Not Complete (3) ................. 4X To Cam Sensor Reference Signal Problem (1) ................................. 24X Reference Signal High (1) .............................. Idle Throttle Angle Too High (1) (4) .................................. Undefined Gear Ratio (1) ....................................... TCC Not Disengaging (1) (4) ..................... Trans. Long Shift & Maximum Adapt (5) (9) ........................ TCC Brake Switch Input Problem (2) (5) ........................ Transaxle Range Signal Problem (2) ......................... Heated Windshield Request Problem (1) .................. Traction Control System PWM Link Failure (1) ...................... Transaxle Shift Solenoid "A" Problem (3) ..................................... Engine Stall Detected (1) ............................... Torque Converter Overstress (9) ................... P/N To D/R Shift At High Throttle Angle (3) (9) .................... Cruise Servo Applied Not In Cruise (2) (4) (5) (6) (7) .. Shorted Brake Vacuum Booster Vac. Sensor (2) (4) (5) (6) (7) ..... Open Brake Vacuum Booster Vac. Sensor (2) .............................. Brake Booster Vacuum Too Low (9) ............................ Stoplight Switch Input Problem (3) ................................. PCM/BCM Data Link Problem (1) .................................... PROM Checksum Mismatch (3) ............................... PCM Keep Alive Memory Reset (10) .................. Alternator "L" Terminal Circuit Problem (3) ...................................... Total EEPROM Failure (3) ......... Open Or Shorted Shift Sol. "A"/"B" Circuit Output (3) ............................. Open Or Shorted Fuel Injector (1) ............................... Active Knock Sensor Failure (1) .............................. Knock Sensor Circuit Failure (9) ...................................... Loss To ABS/TCS Data -

This This This This This This This

fault fault fault fault fault fault fault

turns on Malfunction Indicator Light (MIL). turns on SERVICE VEHICLE SOON message. does not turn on any light or message. disengages TCC and/or transaxle pressure control. disables cruise control for ignition cycle. disables EGR and/or EVAP system. disables long term fuel trim.

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(8) - This fault turns on "THEFT SYSTEM PROBLEM - CAR MAY NOT RESTART" message. (9) - This fault turns on "REDUCED ENGINE POWER" message. (10) - This fault turns on "BATTERY NO CHARGE" message. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ STATUS LIGHTS DISPLAY

Upon entering PCM system level of self-diagnostic mode, indicator lights on Climate Control Center (CCC) are used to indicate status of certain operating modes. Operational status of these components is indicated by corresponding status light being on or off. See Fig. 1.

Fig. 1: Identifying PCM Status Indicators Courtesy of General Motors Corp. SERVICE MODE OPERATION

NOTE:

IPC, ACP, SIR, TCS and RSS systems can also be tested in SERVICE MODE. Only information related to PCM diagnosis is covered in this article.

After PCM trouble codes have been displayed, SERVICE MODE can be used to exit diagnostics or individually perform other tests on different systems. Selecting System Level

G - TESTS W/CODES - 4.6LArticle Text (p. 5)

Following trouble code display, first available system will be displayed (i.e., PCM?). When selecting a system to test, any of following actions may be taken to control display: 1) Depressing HI (fan up) button on CCC will select displayed system for testing (i.e., PCM DATA, PCM INPUTS, PCM OUTPUTS, etc.). See Fig. 2. 2) Depressing LO (fan down) button on CCC will display next available system selection (i.e., IPC?, ACP? or SIR?). This allows display to be cycled through all system choices. This list of systems can be repeated following end of system list. 3) Depressing OFF button on CCC will stop system selection process and return display to beginning of PCM trouble code sequence. Selecting Test Type Level Selection of "DATA?", "INPUTS?", "OUTPUTS?", "OVERRIDES?", "CLEAR CODES?" or "SNAPSHOT?" test type may be displayed. See Fig. 2. If dashes appear in DIC, test is not valid or test conditions are wrong. While selecting a specific test, any of following actions may be taken to control display: 1) Depressing HI (fan up) button on CCC will display a specific output or test parameter for selected test type level (i.e., PCM data parameter PD01,etc.). See Fig. 2. 2) Depressing LO (fan down) button on CCC will display next test type level for system level (i.e., PCM INPUTS?, PCM OUTPUTS?, etc.). See Fig. 2. This allows display to be cycled through all available test type choices. This list of test types can be repeated following display of last test type. 3) Depressing OFF button on CCC will stop test selection process and return display to next system level (i.e., IPC?). Selecting Clear Codes Selecting "CLEAR CODES?" test will result in "CODES CLEAR" message being displayed with selected system name for 3 seconds, indicating all stored trouble codes have been erased from memory. After 3 seconds, display will automatically return to next available test type level (i.e., PCM SNAPSHOT?). After a code has been cleared, make a complete ignition cycle and possibly a test drive. Ensure code does not reset.

G - TESTS W/CODES - 4.6LArticle Text (p. 6)1995 Cadillac Concours

Fig. 2: SERVICE MODE Chart Courtesy of General Motors Corp. PCM LOCATION

PCM is located behind right kick panel. DIAGNOSTIC PARAMETERS PCM SPECIFIC DATA CODES

PD01: Throttle Position (TP) Sensor Display shows degrees of throttle opening from -13.9 to 93.4. G - TESTS W/CODES - 4.6LArticle Text (p. 7)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 9212 PD02: Manifold Air Pressure (MAP) Sensor reading is displayed in kilopascals (kPa) from 10 to 105. With key on, engine off, MAP value will reflect barometric pressure. Multiply local barometric pressure by 3.386 to obtain MAP value within 2 kPa of displayed value with ignition on. MAP will also vary with altitude. PD03: Computed Barometric Pressure (BARO) Reading is displayed in kilopascals (kPa) from 61 to 103.

BARO pressure reading is taken with key on and engine corrected at Wide Open Throttle (WOT). Multiply local pressure by 3.386 kPa to obtain a BARO value within 2 value. BARO varies with altitude (i.e., sea level 100 kPa).

off, and is barometric kPa of displayed kPa, Denver 85

PD04: Engine Coolant Temperature (ECT) Sensor Display shows temperature in degrees Celsius (øC) from -40 to 151. PD05: Intake Air Temperature (IAT) Sensor Reading is displayed in degrees Celsius (øC) from -40 to 151. PD07: EGR Pintle Position Display shows position of EGR pintle in counts from zero to 255 based on feedback PCM receives from EGR valve. PD08: Spark Advance Display shows timing advance in degrees BTDC as generated by ignition control signal from PCM. Range of display is -20 to 70 degrees. PD09: Ignition Ground Voltage Display shows voltage difference between circuit No. 453 (ignition ground) and PCM ground shifted 2.5 volts. A reading of 2.500 volts means ignition and PCM grounds are at the same voltage. A reading of 1.000 means ignition ground voltage is 1.5 volts lower than PCM ground and a reading of 3.500 means ignition ground voltage is 1.0 volt greater than PCM ground. Display shows ignition ground voltage level from .003-4.970 volts. PD10: Fuel Pump Feedback Voltage Voltage measured at fuel pump feedback circuit No. 120. Displayed in volts from zero to 25.5. PD11: Engine Speed (RPM) Displayed in RPM from zero to 6375. PD12: Vehicle Speed (MPH) Displayed in MPH from zero to 255. PD13: EGR Pintle Position (Rescued) Display shows position of EGR pintle in percent of potential pintle travel from zero to 100 based on feedback PCM receives from EGR valve.

PD15: Ignition 1 Voltage G - TESTS W/CODES Display shows ignition voltage measured on circuit No. 539,

PCM pin No. 2D5. Displayed in volts from zero to 25.5. PD16: PCM Output Fault Status A Test shows state of fault lines from 4 of PCM's quad-drivers. Each quad-driver corresponds to one digit of display and each digit can only appear as "0" or "1". A "0" means that no output faults are present. A "1" means that a fault is present in at least one output of that quad-driver. See QUAD-DRIVER IDENTIFICATION TABLE. QUAD-DRIVER IDENTIFICATION TABLE ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

Quad-Driver "A" "B" "C" "D"

(1st (2nd (3rd (4th

Outputs Driven

Digit) (1) .............. TCC Solenoid & Engine Temp. Light Digit) ........ Pass-Key Starter Inhibit Output & EVAP Sol. Digit) ............................ Cooling Fan Relay & MIL Digit) ........... A/C Clutch Relay, TCS Delivered Torque & RSS Lift/Dive Outputs

(1) - "A" will be shown as "1" when brakes are applied. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

PD17: PCM Output Fault Status B Test shows states of fault lines from one PCM quad-driver, the 8 injector drivers and the alternator enable circuit. Each quaddriver corresponds to one digit of display and each digit can only appear as "0" or "1". A "0" means no output faults are present. A "1" means a fault is present in at least one output of that quad-driver. See QUAD-DRIVER IDENTIFICATION TABLE. QUAD-DRIVER IDENTIFICATION TABLE ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

Quad-Driver "E" "F" "G" "H"

(1st (2nd (3rd (4th

Outputs Driven

Digit) (1) .................. TCC Shift Solenoids "A" & "B" Digit) ..................................... Fuel Injectors Digit) (1) .................... Alternator "L" Term. Output Digit) ........................................... Not Used

(1) - "G" will be shown as "1" when ignition is on, engine off. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

PD30: Front Bank Injector Pulse Width Display shows pulse width for cylinders No. 2, 4, 6 and 8 in milliseconds (ms) from zero to 99.6.

PD31: Rear Bank Injector Pulse Width Display shows pulse width for cylinders No. 1, 3, 5 and 7 in G - TESTS W/COD

milliseconds (ms) from zero to 99.6. PD32: Front Oxygen Sensor Voltage Display shows volts from zero to 1.16. PD33: Rear Oxygen Sensor Voltage Display shows volts from zero to 1.16. PD34: Front Oxygen Sensor Cross Counts Display shows counts from zero to 255. Cross count is number of times voltage crosses the .45-volt reference in one second. PD35: Rear Oxygen Sensor Cross Counts Display shows counts from zero to 255. Cross count is number of times voltage crosses the .45-volt reference in one second. PD36: Front Bank Short Term Fuel Trim Display shows counts from zero to 255. Normal integrator count position is 128, indicating engine is operating normally. A count greater than 128 indicates time is being added to injector pulse width, increasing amount of fuel to engine. A count of less than 128 indicates time is being subtracted from injector pulse width, reducing amount of fuel to engine to compensate for a rich condition sensed at front oxygen sensor. PD37: Rear Bank Short Term Fuel Trim Displayed in counts from zero to 255. Normal integrator count position is 128, indicating engine is operating normally. A count greater than 128 indicates time is being added to injector pulse width, increasing amount of fuel to engine. A count of less than 128 indicates time is being subtracted from injector pulse width, reducing amount of fuel to engine to compensate for a rich condition sensed at front oxygen sensor. PD38: Front Bank Long Term Fuel Trim Displayed in counts from zero to 255. Normal count position for long term fuel trim is 128, indicating engine is operating normally. Long term fuel trim value is based on short term learned value, stored in memory blocks of long term according to MAP and RPM values. A count greater than 128 indicates time is being added to injector pulse width, resulting in more fuel to engine. A count of less than 128 indicates time is being subtracted from injector pulse width, resulting in less fuel to engine.

PD39: Rear Bank Long Term Fuel Trim Display shows counts from zero to 255. Normal count position long term fuel trim is 128, indicating engine is operating normally. Long term fuel trim value is based on short term learned value, stored G - TESTS W/CO

in memory blocks of long term memory according to MAP and RPM values. A count greater than 128 indicates time is being added to injector pulse width, resulting in more fuel to engine. A count of less than 128 indicates time is being subtracted from injector pulse width, resulting in less fuel to engine. PD40: Knock Sensor Spark Retard Display shows amount of spark retard due solely to knock sensor input in degrees from zero to 44.8. PD41: Knock Sensor Display shows the number of instances of engine detonation detected by knock sensor in 1/8 of a second from zero to 255. PD42: Octane Level Of Fuel Display shows octane level of fuel based on recent knock sensor activity. This parameter will only display zero, 87, 90 or 93 indicating fuel octane calculated by PCM. A parameter value of zero indicates that PCM has not enough time to calculate the octane level. Display will always read zero for vehicles equipped with 4.6L (VIN Y) engine. PD69: Cruise Lash Display shows amount of cruise lash as a percentage of cruise servo travel from 0.0-99.9 percent. Cruise lash in amount of slack found in cruise control cable at closed throttle. A normal cruise lash percentage should be 13-31 percent. PD70: Cruise Control Feedback Display shows percentage of servo apply as measured by servo position sensor. Zero equals no vacuum and 99 equals full vacuum (full apply). PD71: Transaxle Pressure Switch Display shows selected transaxle gear based on input from transaxle pressure switch in a 3-digit binary code from 000-111. Display will read 111 with key on, engine off. TRANSAXLE PRESSURE SWITCH BINARY CODE TABLE ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

Code 000 001 010 011 100 101

Gear Range

........................................................ Illegal ........................................................ Drive 4 ........................................................ Illegal ........................................................ Drive 3 ........................................................ Reverse ................................................... Park/NeutralG - TESTS W/CO

110 111

........................................................ ........................................................

Drive 1 Drive 2

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PD72: Transaxle Input Speed Display shows the turbine shaft speed from zero to 8192 RPM. PD73: Torque Converter Slip Speed Display shows amount of slippage between engine and transaxle input shaft from zero to 8192 RPM. PD74: Transaxle Pressure Control Solenoid Current Display shows calculated current output from PCM to drive the transaxle pressure control solenoid. This current is calculated by PCM based on the duty cycle of the signal it is sending out and is displayed in amps from 0-4.98. PD75: Current Error Transaxle pressure control solenoid current error. Display shows difference between calculated transaxle pressure control solenoid current output and that measured by the PCM at pin No. 2C15 across the control solenoid current feedback resistor. PD76: Transaxle Gear Ratio Display shows calculated gear ratio of transaxle based on transaxle input speed and vehicle speed with the final drive ratio subtracted out. If gear ratio difference is greater than 5 percent of specified ratio, Code P086 will set. See TRANSAXLE GEAR RATIO table. TRANSAXLE GEAR RATIO TABLE ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

Gear 1st ........................................................... 2nd ........................................................... 3rd ............................................................ 4th ........................................................... Reverse .......................................................

Ratio 2.96 1.63 .00 0.68 2.13

ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

PD77: Transaxle Oil Temperature Display shows transaxle oil temperature in degrees Celsius from -40 to 152.

PD78: Transaxle Shift Adapt Display shows readings of -128 to +127 psi. This value is the increase or decrease in transaxle line pressure that PCM is commanding through the transaxle pressure control solenoid during the most recentG - TESTS W/CO

upshift or downshift. PCM increases or decreases line pressure during shifts to control shift feel. Normal value fluctuates within a range of 20 psi. A value less than zero psi means PCM was lowering transaxle line pressure during most recent shift to soften the shift. A value greater than zero psi means PCM was raising transaxle line pressure during most recent shift to firm up the shift. PD79: Transaxle Steady State Adapt Display shows pressure from zero to +127 psi. This value is the increase in transaxle line pressure that PCM is commanding through the transaxle pressure control solenoid during steady state, not upshifting or downshifting condition. PCM increases line pressure to control clutch slippage. Normal value is 0-10 psi. A value greater than zero psi means that PCM has detected some clutch slippage (not during transaxle shifts) and is raising transaxle line pressure to decrease transaxle clutch slippage. PD80: Transaxle Garage Shift Adapt Displayed in seconds from-3000 to +3000. PCM increases or decreases line pressure during garage shifts (shifts from Park or Neutral to Drive or Reverse) to control shift feel. This value is the increase of decrease in garage shift duration/length that PCM is trying to achieve by adjusting transaxle line pressure up or down. A normal value is between -1.0 and +1.0 second. PD81: TCC Solenoid Duty Cycle Display shows the current duty cycle (on time as a percent of cycle time) of the PCM's TCC solenoid output from zero to 99.6 percent. PD82: Transaxle Shift Time Display shows amount of time elapsed between when transaxle left the previous gear ratio and arrived at the current gear ratio. Shift time is measured from zero to 6.375 seconds. PD83: Non-Drive Wheel Speed Display shows speed of rear wheels as sent across the UART data link (circuit No. 800) from EBTCM. Measured in km/h from 2-255. PD84: Brake Booster Vacuum Display shows vacuum level (with respect to atmosphere) in brake booster in kPa from -10.65 to 83.4 (about 24.6 in Hg). PD97: PROM Calibration (Transaxle) Display shows a 3-digit code that uniquely identifies the program stored in PROM for transaxle control calibration.

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PD98: Ignition Cycle Counter Display shows counts from 1-50. Count increases by one with each on-to-off cycle. When a trouble code sets, counter is set to zero. If trouble code becomes history, counter will increase by one with each key cycle until another code is set or until key has been cycled 50 times, at which point code will be erased. PD99: PCM Programmable Read Only Memory (PROM) ID Code Display shows a 4-digit code identifying program stored in PROM for engine control calibration. PCM SPECIFIC INPUT CODES

PCM input selections provide testing of inputs to PCM. Input status is shown on display as HI or LO. Input test status is shown as "0" until PCM sees a transition in state of switch; status then changes from "0" to "X", indicating test has been passed. PI70: Cruise Control Brake Switch Ensure cruise control switch is in ON position. Test detects opening and closing of cruise control brake switch at PCM terminal No. No. 2D12. See Fig. 3. PI70 should be HI with pedal released and LO with brake pedal depressed. PI71: Torque Converter Clutch (TCC) Brake Switch Test detects opening and closing of TCC brake switch at PCM terminal No. No. 2D13. See Fig. 3. PI71 should be HI with brake pedal released and LO with brake pedal depressed. PI72: Throttle Position Switch Test detects opening and closing of Idle Speed Control (ISC) nose switch at PCM terminal No. 2D8. See Fig. 3. PI72 should be LO with accelerator pedal released and HI with accelerator pedal depressed. PI79: Transaxle Switch In Park/Neutral This input come to PCM terminal No. 2D9. PI79 should be LO when transaxle is in Park or Neutral and HI when transaxle is in Reverse or any drive gear. PI82: Cruise Control ON/OFF Switch Test detects opening and closing of CRUISE switch mounted on turn signal lever at PCM terminal No. 2D14. See Fig. 3. PI82 should be LO with cruise control switch off and HI with cruise control switch on.

PI83: Cruise Control SET/COAST Switch Test detects closing of14)SET/COAST switch at terminal AcePCM Mechanics 123 MainNo. Street San Diego Ca 921 1995 Cadillac ConcoursFor G - TESTS W/CODES - 4.6LArticle Text (p.

2D15. See Fig. 3. PI83 should be LO with cruise control switch off and HI with cruise control switch on. PI84: Cruise Control RESUME/ACCEL Switch This test detects closing of RESUME/ACCEL switch at PCM terminal No. 2D16. See Fig. 3. PI84 should be LO with cruise control switch off and HI with cruise control switch on. PI85: Power Steering Pressure (PSP) Switch This input comes from PCM terminal No. 1A5. PI85 should be HI with steering wheel on center and LO with engine running and steering wheel at full lock (left or right) position. PI86: Extended Travel Brake Switch This test detects closing of brake switch. This input comes to PCM terminal No. 2C7. PI86 should be HI with brake pedal released and LO with brake pedal depressed. PI87: Low Engine Coolant Level Switch This input comes to PCM terminal No. 1B16. PI87 should be HI with sufficient coolant in the coolant overflow bottle and LO with coolant level. PI89: Stoplight Switch This input comes through the data link from the EBTCM. PI89 should be LO with brake pedal released and HI with brake pedal depressed.

Fig. 3: Identifying Red PCM Harness Connector Courtesy of General Motors Corp.

Fig. 4: Identifying White PCM Harness Connector Courtesy of General Motors Corp.

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Fig. 5: Identifying Blue PCM Harness Connector Courtesy of General Motors Corp. NOTE:

All PCM specific output tests are to be performed with key on, engine off.

PCM OUTPUTS option provides ability to cycle PCM-controlled outputs. DIC display identifies solenoid or relay and state PCM is commanding that device. HI indicates solenoid or relay is de-energized and LO indicates solenoid or relay is energized. See Fig. 1. PO00: No Outputs No outputs are cycled. PO01: EVAP Solenoid Evaporative canister purge solenoid will cycle on and off about every 4 seconds. PO02: Torque Converter Clutch (TCC) TCC solenoid will cycle on and off about every 4 seconds. PO03: EGR Solenoid EGR solenoid will cycle on and off about every 4 seconds. PO06: No Overrides No overrides are active at this point. PO07: Idle Speed Control (ISC) Motor ISC will alternately extend plunger for 2 seconds and then retract plunger for 2 seconds. PO08: Cruise Control Vent Cruise control vent solenoid. Solenoid will cycle on and off about every 4 seconds. PO09: Cruise Control Vacuum Cruise control vacuum solenoid will cycle on and off about every 4 seconds.

G - TESTS W/CODES - 4.6LArticle Text (p. 16)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

PO10: Shift "A" Transaxle shift solenoid "A" will cycle on and off about every 4 seconds. PO11: Shift "B" Transaxle shift solenoid "B" will cycle on and off about every 4 seconds. PO20: A/C Compressor Clutch Relay A/C clutch control relay will cycle on and off about every 4 seconds. PO21: Transaxle Pressure Control (TPC) Solenoid TPC solenoid will cycle on and off about every 4 seconds. PCM SPECIFIC OVERRIDE CODES

PCM override feature allows testing of certain system functions regardless of normal program instructions, provided test conditions are met. When a test is selected, current mode of function will be displayed as a percentage on Driver Information Center (DIC). If test conditions are not met, DIC will display "==" instead of override value selected. DIC display will alternate between "--" and normal programmed command. Depressing WARMER button will increase override value and depressing COOLER button will decrease override value. Upon release of button, display may either remain at overridden value or automatically return to normal program control, depending on which function is being overridden. Selection of another override test will cancel current override. PS00: No Outputs No outputs/overrides are active at this point. PS01: Torque Converter Clutch (TCC) Solenoid TCC solenoid is energized by WARMER button and deactivated by COOLER button. DIC will display "99" for on and "00" for off. TCC can only be enabled when transaxle is in 3rd or 4th gear.

PS02: EGR Solenoid PS02 may be used to override normal EGR solenoid control. When PS02 is first selected, display will alternate between "--" for one second and current commanded EGR pintle position (as a percent of full travel). Depressing WARMER button will increment commanded EGR pintle position up to maximum of 99%. Depressing COOLER button will decrement commanded EGR position down to minimum of 0%. Current commanded EGR pintle position will be displayed throughout the override. G - TESTS W/CODES - 4.6LArticle Text (p. 17)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

PS03: Idle Speed Control (ISC) Motor ISC motor may be overridden under certain conditions using PS03. When PS03 is first selected, display will alternate between "--" for one second and "50" for 3 seconds to indicate normal PCM control of ISC motor. This will continue until ISC extend or retract override is attempted. ISC motor may be extended using the WARMER button only when following conditions are met: * * * *

Engine not running Vehicle speed at zero Transaxle in Park or Neutral TP sensor closed or throttle angle (PD01) at less than 1.44 degrees.

When these conditions are met, ISC will extend as far as it can and "99" will be displayed. ISC motor may be retracted using the COLDER button only when vehicle speed is zero and transaxle is in Park or Neutral. When these conditions are met, ISC will retract until throttle switch opens and "00" will be displayed. While in this override, EGR solenoid and alternator will be commanded off and ignition control will try to maintain at least 450 RPM. PS04: Injector Disable (Power Balance) 1) Test conditions are engine running, transaxle in Park or Neutral and vehicle speed zero. Desired engine RPM should be selected before selecting this override as ISC will stay at a selected RPM. 2) Depressing WARMER button will select an injector and cycle injectors at a rate of one selection (next injector) per second. DIC will display injector selected. Depressing COOLER button will cause injector cut-off and DIC will display injector "00". PS05: Fuel Pump Relay 1) Test conditions are transmission in Park or Neutral and vehicle speed at zero. When PS05 is first selected, DIC display will alternate between "==" for one second and the current state of the fuel pump relay output for 5 seconds. 2) Depressing COOLER button will turn relay off and display "00". Depressing WARMER button will turn relay on and display "99". Normal control will resume as soon as button is released. PS06: No Outputs Not used. No outputs are cycled.

PS07: Cruise Control Servo Position 1995 Cadillac Ace Mechanics 123 Main Street San G - TESTS W/CODES - 4.6LArticle (p. 18)be 1) Before testing, engine Text should run to ConcoursFor charge vacuum

reservoir. Test conditions are transmission in Park or Neutral and engine off. With no buttons depressed, system remains at selected override. 2) Depressing WARMER button will cause servo to retract. DIC panel display will change from "00" to "99". Depressing COOLER button will cause servo to extend. DIC panel display will change from "99" to "00". PS08: Cooling Fan Relays 1) The current state of the high and low speed fan relay outputs will be displayed as 2-digits. The left digit represents the low speed relay state and the right digit the high speed fan relay state. A "1" indicates relay is energized; a "0" indicates relay is de-energized. 2) Depressing WARMER button on CCC changes the high speed fan relay state to "1" if it was "0" or vice-versa. Depressing COOLER button on CCC changes the low speed relay state to "1" if it was "0" or vice-versa. There are 4 possible states of the cooling fan relays and their corresponding cooling fan operation. See COOLING FAN RELAY OUTPUT STATE table. COOLING FAN RELAY OUTPUT STATE TABLE ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

Output State "00" "01" "10" "11"

Fan Operation

.................................................. All Fans Off ............................................. Right Fan On High .............................................. Both Fans On Low ............................................. Both Fans On High

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PS09: Temporary Spark Advance 1) Test conditions are transaxle in Park or Neutral and engine running. Calculated advance will be displayed when this test is selected. First time COOLER button on CCC is depressed, PCM will fix spark advance to 10ø BTDC; DIC will display "10". 2) By depressing COOLER button a second time, PCM will calculate a 1-2 degree timing retard, to a minimum of zero. Depressing WARMER button will increase spark advance up to maximum advance calculated by PCM. If an advance selected is greater than calculated value, "==" will be displayed.

PS10: Injector Flow 1) Test conditions are engine off, transaxle in Park or Neutral. PS10 may be used to fire each fuel injector to compare injector flow. When PS10 is first selected, the display will alternate between "==" for one second and "08" for 5 seconds ("08" signifying injector No. 8). G - TESTS W/CODES -

2) Depressing COOLER button selects the injector to be tested and the WARMER button is used to fire the selected injector. Depressing COOLER button again will select another injector for testing and depressing WARMER button will fire the selected injector. While an injector is fired, display will show "99". PS10 will only allow each injector to be fired once between engine restart to avoid flooding. PS11: Transaxle Shift 1) Test conditions are shift selector in "D4" and vehicle speed less than 65 MPH. This override places transaxle in selected gear until WARMER or COOLER buttons are depressed to change gear selection. 2) PCM will prevent a downshift from 2nd to 1st gear at speeds greater than 30 MPH and from 3rd to 2nd gear at speeds greater than 60 MPH. When no button is depressed, transmission remains at selected override position. 3) Each time COOLER button is depressed, transmission will downshift one gear. DIC will display gear number/position selected. 4) Each time WARMER button is depressed, transmission will upshift one gear. DIC will display gear number/position selected. PS12: Long Term Fuel Trim Reset PS12 may be used to reset long term fuel trim values to 128 (neutral). When PS12 is selected, "00" will be displayed. Depressing COOLER button will cause all block learn values to reset to 128 and "90" to be displayed. Depressing WARMER button will not do anything. PS13: Learn & Adapt Reset PS13 may be used to reset TP sensor learn and idle learn values and/or garage shift adapt values. When PS13 is selected, "00" will be displayed. Depressing WARMER button will reset the garage adapt values and cause "09" to be displayed. Depressing COOLER button will reset TP sensor learn and idle learn values and cause "90" to be displayed. Ignition should be turned off for at least 30 seconds for learned TP sensor values to reset. Each reset is allowed only once per ignition cycle. PS14: Transaxle Adapt Reset PS14 may be used to reset transaxle upshift adapt values and/or transaxle steady state adapt values. When PS14 is selected, "00" will be displayed. Depressing WARMER button will reset transaxle steady state adapt values and cause "09" to be displayed. Depressing COOLER button will reset transaxle upshift adapt values and cause "90" to displayed.

PS15: Transaxle Oil Life Ace Mechanics 123 Mai 1995 Cadillac ConcoursFor Transaxle oil life index is calculated and maintained by PCM. G - TESTS W/CODES - 4.6LArticle Text (p. 20)

When P15 is selected, the current transaxle oil life index (in percent) will be displayed. The symbol "--" is displayed to indicate 100 percent. Depressing WARMER button will increment transaxle oil life index up to 100 percent ("--"). Depressing COOLER button will decrement oil life index to zero. Ignition must be turned off for at least 30 seconds to allow new transaxle oil life index value to be saved. PS20: Transaxle Pressure Control 1) P20 may be used to override control of the transaxle pressure control solenoid, thus overriding transaxle line pressure. When PS20 is selected, DIC display will alternate between "--" for one second and commanded transaxle line pressure (in psi) for 5 seconds until either the WARMER or COOLER button is depressed. PS20 override operates differently depending the gear selector position. 2) Ensure gear selector is in Park or Neutral, vehicle speed is at zero, A/C clutch disabled, and engine speed at 1150-1250 RPM. WARMER button may be used to increment commanded line pressure and COOLER button to decrement commanded line pressure. Current commanded line pressure will be displayed for the duration of the override. 3) With gear selector not in Park or Neutral, depressing the WARMER button will increment commanded line pressure. Depressing COOLER button will have no effect. Current commanded line pressure will be displayed for the duration of the override. PS21: Knock Sensor Test 1) Test conditions are transaxle in 4th gear, throttle angle at greater than 33.6 degrees and coolant temperature at greater than 80øC. When PS21 is selected, display will alternate between "--" for one second and "99" for 5 seconds. 2) If COOLER button is depressed and held down, display will change to "00" and TCC will engage and spark advance will jump up to 21 degrees and stay there for about 7.4 seconds. 3) If knock sensor activity is detected anytime during the test, display will change to "11" and the test is suspended. If end of test is reached and no knock sensor activity was detected, display will change to "22". PS22: Permanent Spark Retard PS22 may be used to permanently restart ignition base timing of 10ø BTDC by up to 4ø BTDC. When PS22 is selected, the current permanent spark override will be displayed by either "00" for no record or the number of degrees timing was retarded ("94" for 4ø retard). Depressing COOLER button retards base timing a maximum of 4ø. Depressing WARMER button will display "00" and resets timing to 10ø BTDC. Ensure ignition is turned off for at least 30 seconds to save new permanent spark retard value.

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PS23: Alternator Enable/Disable PS23 may be used to enable or disable alternator charging using the PCM's "L" terminal output. Test conditions are transaxle gear selector in Park or Neutral and engine running. When PS23 is selected, display will alternate between "--" for one second and the current state of PCM's "L" terminal output ("99" for enabled and "00" for disabled) for 5 seconds. Depressing WARMER button will enable alternator charging. Depressing COOLER button will disable alternator charging. The current state of PCM's "L" terminal output will be displayed for the duration of the override. PS24: Traction Control Disable PS24 may used to temporarily disable traction control. When PS24 is selected, display will alternate between "--" for one second and the current state of traction control disable override ("99" for override active and "00" for override inactive). Depressing WARMER button will disable traction control for the next 11 ignition cycles and display "99". Depressing COOLER button will allow normal program control of traction control and display "00". "TRACTION CONTROL DISABLED" message will appear for the duration of this override and is normal. PCM CLEAR CODES

If PCM CLEAR CODES option is chosen, PCM will clear all stored PCM trouble codes. PCM SNAPSHOT

Selection of SNAPSHOT test type will allow the recall of all "DATA" and "INPUT" values for the selected system from specific point in time. These values may be retrieved for either a snapshot that was manually triggered, or if the selected system allows a snapshot from the setting of last PCM trouble code. Snapshot may be selected by depressing HI button on CCC. If snapshot for a set PCM trouble code is present, display will read "PXXX" (XXX being 3-digit code) when snapshot is first selected. Snapshot can be by-passed by depressing LO button. This selection process may continue until all stored PCM codes with snapshot information are displayed. At this point, the manual snapshot display "TAKE SNAPSHOT?" will appear. Depressing LO button will return system to start of snapshot process, if desired. If no stored PCM codes are available or all stored codes with snapshot information are by-passed, display will read "TAKE SNAPSHOT? ". A manually triggered snapshot may be taken at this point by depressing the HI button. Display will read "SNAPSHOT TAKEN" and will change to "SNAP DATA?" within several seconds.

G - TESTS W/CODES - 4.6LArticle Text (p. 22)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921 VIEWING SNAPSHOT INFORMATION

After snapshot has been taken or a code set snapshot selected, display will read "SNAP DATA?" or "PXXX DATA". Any of following actions may be taken to control display. 1) Depressing HI button on CCC will select data values for the snapshot. At this point, display is controlled as it would be for non-snapshot data displays, however, all values represent memorized vehicle conditions. 2) Depressing LO button will allow for snapshot INPUT values to be selected. Display will read "SNAP INPUTS" or "PXXX INPUTS". 3) Depressing OFF button on CCC will return to original snapshot screen. Depressing OFF button several times will return display to the next available test selection. EXITING DIAGNOSTICS

To exit self-diagnostics, depress AUTO or DEFOG buttons on CCC or turn ignition off. Turning off ignition will not clear stored PCM trouble codes. NOTE:

In the following flow charts, vehicles equipped with Sequential Multiport Fuel Injection (SFI) are also referred to as Port Fuel Injection (PFI).

SFI CHARTS SFI CHART C-1, FUEL SYSTEM CHECK

This test provides a quick analysis of fuel system. This chart then identifies more detailed diagnosis required based on symptoms present.

G - TESTS W/CODES - 4.6LArticle Text (p. 23)1995 Cadillac ConcoursFor Ace M

Fig. 6: SFI Chart C-1 Schematic, Fuel System Check Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 24)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

G - TESTS W/CODES - 4.6LArticle Text (p. 25)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 7: SFI Chart C-1 Diagnostic Flow Chart, Fuel System Check Courtesy of General Motors Corp.

SFI CHART C-2, FUEL PRESSURE CHECK

This test determines if fuel system is providing fuel pressure. Components involved include fuel tank, sender, pump, pipes and hoses, pressure regulator, fuel rail, and injectors. Electrical operation of fuel pump relay is also checked. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If fuel pump does not operate with ignition on, diagnose as if a Code P020 is set to determine cause. If fuel pump operates with ignition on, check for clogged fuel filter or fuel line. 2) If fuel pressure is normal, check for proper injector operation. 3) If fuel pressure is too high, pressure regulator is not working properly, or cannot work due to a restriction in fuel return line to fuel tank. 4) Fuel pressure leak-down can be caused by faulty pressure regulator, a fuel pump check ball, or a leaking injector. Low fuel pressure that does not leak down can be caused by a faulty pressure regulator or a low output fuel pump. 5) If fuel pressure holds with fuse A5 removed (in engine compartment fuse block), injectors No. 2, 3, 5 or 8 must have been energized causing fuel pressure drop. 6) Checks if a short to ground on the low side of injector or PCM was keeping injectors energized. 7) If fuel pressure holds with fuse A7 removed (in engine compartment fuse block), injectors No. 1, 4, 6 and 7 must have been energized causing fuel pressure drop. 8) Checks if short to ground on low side of injectors or PCM was keeping injector energized. 9) Checks for physical cause of pressure drop, such as leaking injectors, leaking fuel rail or pressure regulator. If no leaks are found, fuel pump check ball is not operating properly. Replace fuel pump.

G - TESTS W/CODES - 4.6LArticle Text (p. 26)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 8: SFI Chart C-2 Schematic, Fuel Pressure Check Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 27)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

G - TESTS W/CODES - 4.6LArticle Text (p. 28)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 9: SFI Chart C-2 Diagnostic Flow Chart - 1 Of 2, Fuel Pressure Check Courtesy of General Motors Corp.

Fig. 10: SFI Chart C-2 Diagnostic Flow Chart - 2 Of 2, Fuel Pressure Check Courtesy of General Motors Corp. SFI CHART C-3, INJECTOR FLOW & VOLTAGE DROP CHECK

This procedure compares fuel pressure drop when each injector is pulsed for a set amount of time. Since each injector is pulsed the same, fuel pressure drop for each injector should be about the same. Faulty injector can be identified by either too high or too low fuel pressure drop. This procedure also determines if injector voltage drop is within specification. Injector voltage dropping out of specification can cause driveability conditions that are intermittent or that do not show up during injector flow check. This test requires the use of Fuel Pressure GaugeText (J (p. 34730G - TESTS W/CODES - 4.6LArticle 29)1995 Cadillac Concours

1), DVOM and Fuel Injector Tester (J 39021). NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Install Fuel Injector Tester (J 39021). Select PS05 for 5 seconds to energize fuel pump and build up fuel pressure. Select individual injector with PS10 to check fuel pressure drop associated with each injector. No fuel pressure drop indicates that injector did not operate. This could be caused by a faulty injector or circuit problem. A substantial injector fuel pressure drop indicates a faulty injector. 2) Checks if fuse is open causing either injectors No. 2, 3, 5 and 8 or injectors No. 1, 4, 6 and 7 not to operate. 3) Checks if circuits No. 239 or 439 is open from fuse and harness connector. 4) Fuel pressure must be released before testing to avoid flooding. 5) Subtract .55 volts from highest recorded value (less than 9.5 volts) to establish the lowest acceptable value. Any injector below the established value must be replaced. 6) Any injector with greater than 2 psi difference from the other injectors is faulty and must be replaced. Inspect for deposits and restrictions and investigate source of contamination. 7) Checks for open or shorted fuel injector or injector circuit. 8) Checks if PCM cannot control injector or if PCM is not receiving injector voltage due to an open between injector and PCM connector. 9) Release fuel pressure before testing to avoid flooding. 10) Checks for open or shorted fuel injector harness. Resistance should be 8-25 ohms. 11) Checks if PCM cannot control injector or if PCM is not receiving injector voltage due to an open between injector and PCM connector.

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Fig. 11: SFI Chart C-3 Schematic, Injector Flow & Voltage Drop Check Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 31)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

G - TESTS W/CODES - 4.6LArticle Text (p. 32)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 12: SFI Chart C-3 Diagnostic Flow Chart - 1 Of 3, Injector Flow & Voltage Drop Check Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 33)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 13: SFI Chart C-3 Diagnostic Flow Chart - 2 Of 3, Injector Flow & Voltage Drop Check Courtesy of General Motors Corp.

Fig. 14: SFI Chart C-3 Diagnostic Flow Chart - 3 Of 3, Injector Flow & Voltage Drop Check Courtesy of General Motors Corp. SFI CHART C-4, POWER BALANCE TEST

This test checks performance of each cylinder by comparing it to other cylinders. PCM shuts off fuel for a given cylinder in its intake cycle. This measures performance of that cylinder by amount of RPM drop caused by that cylinder not producing a power stroke. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Idle quality should get worse when an injector is disabled. Engine should miss and idle will become rough. 2) Unequal performance of cylinders during this check indicates an ignition or mechanical problem, assuming fuelText system has Cadillac Concours G - TESTS W/CODES - 4.6LArticle (p. 34)1995

already been checked. Diagnose ignition system before checking for an engine mechanical problem. 3) If fuel system and power balance checks okay, check EGR, EVAP or PCV system for possible problem.

Fig. 15: SFI Chart C-4 Schematic, Power Balance Test Courtesy of General Motors Corp.

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Fig. 16: SFI Chart C-4 Diagnostic Flow Chart - 1 Of 2, Power Balance Test Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 36)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 17: SFI Chart C-4 Diagnostic Flow Chart - 2 Of 2, Power Balance Test Courtesy of General Motors Corp. SFI CHART C-5, FUEL LEAK/ODOR CHECK

This procedure provides a means of identifying a fuel system component that is causing a leak. This check also provides information on how to diagnose a fuel odor condition. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Vehicle should be operated under same conditions as when leak/odor occurred. 2) Nylon fuel lines are not repairable and must be replaced. 3) EVAP system problem or a rich engine operation may cause a fuel odor condition.

Fig. 18: SFI Chart C-5 Diagnostic Flow Chart, Fuel Leak/Odor Check Courtesy of General Motors Corp. SFI CHART C-6, IDLE SPEED CONTROL (ISC) CHECK

This test verifies ISC motor operation and checks ISC plunger adjustment. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) This checks for a high minimum air idle which could cause a sail-on condition. High minimum air idle is okay if engine cannot stay running at minimum air idle. 2) Perform Code P030 diagnosis to identify cause of faulty ISC motor. 3) This determines ISC authority. This is determined by comparing minimum TP sensor value to the maximum ISC extend value. ISC authority should be adjusted to 10-11 degrees of throttle angle. 4) TP sensor idle learn procedure must be performed after ISC plunger adjustment.

G - TESTS W/CODES - 4.6LArticle Text (p. 37)1995 Cadillac Concours

Fig. 19: SFI Chart C-6 Schematic, Idle Speed Control (ISC) Check Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 38)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

G - TESTS W/CODES - 4.6LArticle Text (p. 39)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 20: SFI Chart C-6 Diagnostic Flow Chart, Idle Speed Control (ISC) Check Courtesy of General Motors Corp. POWERTRAIN CHARTS POWERTRAIN CHART 1, POWERTRAIN SYSTEM CHECK

POWERTRAIN SYSTEM CHECK is an organized approach to identifying a computer-controlled electronics problem. Understanding chart and using it correctly will reduce diagnostic time and prevent unnecessary parts replacement. Use POWERTRAIN SYSTEM CHECK to begin diagnosis if any

customer complaint does not directly relate to a specific subsystem. If Malfunction Indicator Light (MIL) fails to illuminate during cranking, problem could be in PCM power supply circuit. POWERTRAIN SYSTEM CHECK will direct technician to an appropriate diagnostic chart, test procedure in appropriate article. If DIC panel display is not operating properly, PCM selfdiagnostics mode cannot be used and POWERTRAIN SYSTEM CHECK will direct technician to an appropriate diagnostic chart, test procedure in appropriate article. If a trouble code is identified by PCM computer system selfdiagnostics mode, problem can be corrected following appropriate numbered code charts. If no trouble code has been identified, POWERTRAIN SYSTEM CHECK will direct technician to an appropriate diagnostic chart, test procedure in appropriate article. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if system will enter diagnostics. If diagnostics cannot be entered or displays are blank, problem exists in IPC or related circuit. Diagnose system as follows: *

*

*

*

*

Turn ignition on. Using a DVOM connected to ground, backprobe IPC connector cavities A1, A2, C12 and C14. Reading should be greater than 10 volts. If voltage reading on one or more terminal is not as specified, repair open or short in related circuit. If voltage reading is not as specified on all terminals, check charging system. If all of voltage readings are correct, turn ignition off. Disconnect IPC connectors (Black and White). Measure resistance between ground and IPC connector cavities A5 and C16. If any measurement is greater than one ohm, repair affected circuit or check/repair ground. If both circuits are less than, reconnect IPC connectors. Turn ignition on. Using a DVOM connected to ground, backprobe IPC connector cavity B2. If reading is 14 volts or greater, check IPC connectors for good terminal contact. If contacts are okay and diagnostics still cannot be entered, replace IPC. If reading is less than 14 volts, disconnect radio head and measure voltage at IPC connector terminal B2. If reading is 14 volts or greater, replace radio head. If reading is less than 14 volts, disconnect IPC connector. Check continuity between IPC connector terminal B2 and ground. If continuity is present, repair short in circuit. If continuity is not present, replace IPC assembly.

2) Checks to see if IPC is able to communicate with PCM. If G -PCM TESTS W/CODES - 4.6L IPC is unable to communicate with PCM, Code I034 will set or NO

DATA message will be displayed when diagnostics are used. 3) MIL should be on when vehicle is in diagnostic mode. 4) Checks if powertrain system is operational. 5) Checks if PCM codes are present. 6) MIL should be off if codes are not present. 7) Checks if known customer complaint is causing problem. 8) If complaint is not in customer complaint list, perform system check applying to situation.

Fig. 21: Powertrain Chart 1 Schematic, Powertrain System Check Courtesy of General Motors Corp.

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G - TESTS W/CODES - 4.6LArticle Text (p. 42)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 22: Powertrain Chart 1 Diagnostic Flow Chart, Powertrain System Check Courtesy of General Motors Corp.

POWERTRAIN CHART 2, PCM POWER & GROUND CHECK

Battery voltage is present at all times at PCM terminals No. 2C4 and 2D4 through circuit No. 840 from engine compartment fuse block, fuse B13. PCM is also fed IGN 1 (hot in run, bulb test and start) at PCM terminal No. 2D5 through circuit No. 539 from engine compartment fuse block, fuse A9. PCM needs both battery and IGN 1 voltage to operate. PCM grounding points are at PCM terminals No. 2C2, 2C3, 2D2 and 2D3 through circuit No. 451 to ground (circuit G102). NOTE:

Test numbers refer to numbers on diagnostic chart.

1) This test checks for data line codes that would indicate that entire data line is down. 2) Checks for battery voltage on circuit No. 840. If voltage is measured at one terminal and not other, check circuit No. 840 for an open to connector C205. If voltage is not measured at either terminal, check fuse B13 and circuit No. 840 to C205 for an open. 3) Checks circuit No. 539 and fuse A9 for open. 4) Checks for open circuit at circuit No. 451. If voltage measures greater than .1 volt on 1-3 wires, repair open to circuit S234. If voltage measures greater than .1 volt on all 4 wires, repair open from circuit S234 to G102 (ground). 5) Checks for an open in circuit No. 451 or inside PCM. 6) Checks if data line is open or shorted to ground or voltage, causing a PCM problem.

Fig. 23: Powertrain Chart 2 Schematic, PCM Power & Ground Check Courtesy of General Motors Corp. G - TESTS W/CODES - 4.6LArticle Text (p. 43)1995 Cadillac Concours

Fig. 24: Powertrain Chart 2 Diagnostic Flow Chart, PCM Power & Ground Check Courtesy of General Motors Corp. G - TESTS W/CODES - 4.6LArticle Text (p. 44)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

POWERTRAIN CHART 3, POWERTRAIN GROUND CHECK

Circuit G401 is ground location for fuel pump. Circuit G100 is battery ground. Circuit G102 is ground for all powertrain electronics, including PCM. Loose or poor ground connections may cause a variety of problems, including flickering telltales, PCM codes and several driveability problems. POWERTRAIN GROUND CHECK should be performed when referred to by other diagnostics or when erratic or intermittent problem is present. These 3 vehicle grounds are essential for proper powertrain system operation. They are: * * *

Circuit G100, located near battery. Circuit G102, located on right rear corner of engine block. Circuit G401, located on front side of left rear seat diagonal brace.

Fig. 25: Powertrain Chart 3 Schematic, Powertrain Ground Check Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 45)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

G - TESTS W/CODES - 4.6LArticle Text (p. 46)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 26: Powertrain Chart 3 Diagnostic Flow Chart, Powertrain Ground Check Courtesy of General Motors Corp.

POWERTRAIN CHART 4, MIL INOPERATIVE

PCM controls Malfunction Indicator Light (MIL) through circuit No. 419. Light is on when PCM has detected a problem that will affect vehicle emissions or may cause powertrain damage or driveability problems. MIL will glow when certain PCM trouble code(s) are present or when system is in diagnostic mode. MIL light will not glow when ignition is on and engine is not running or when engine is running and no PCM code are current. Some codes are stored without activating MIL light. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks 3rd digit of PD16 to determine is PCM is receiving correct input voltage. If MIL is illuminated, PCM expects to see zero volts in terminal 3F5. If it is, the 3rd digit of PD16 will be zero. If it sees greater than zero volts, the 3rd digit will be "1". 2) This test checks if correct voltage is being received at PCM and if it is processed correctly. 3) Checks for an open in circuit No. 419. 4) Checks for voltage to high side of MIL bulb.

Fig. 27: Powertrain Chart 4 Schematic, MIL Inoperative Courtesy of General Motors Corp. G - TESTS W/CODES - 4.6LArticle Text (p. 47)1995 Cadillac Concours

Fig. 28: Powertrain Chart 4 Diagnostic Flow Chart, MIL Inoperative Courtesy of General Motors Corp. POWERTRAIN CHART 5, MIL ON (NO CODES PRESENT)

PCM controls MIL through circuit No. 419. Light will illuminate when PCM detects a problem that will affect vehicle emissions, or cause powertrain damage or driveability problems. MIL will illuminate when certain PCM trouble codes are present or when system is in diagnostic mode. MIL will not illuminate when ignition is on and engine is not running or when engine is running and no PCM codes are current. Some codes are stored without activating MIL. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) With ignition on, MIL should be off. Check if any other fault is present. 2) Check for diagnostic code(s) causing MIL 123 to Main Street San Diego Ca 921 1995 Cadillac ConcoursFor Ace Mechanics G - TESTS W/CODES - 4.6LArticle Text (p. 48)trouble

illuminate. 3) If MIL goes off when PCM connector 3E/3F is disconnected, replace PCM. If MIL stays on, repair circuit No. 419 for a short to ground.

Fig. 29: Powertrain Chart 5 Schematic, MIL On (No Codes Present) Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.

Fig. 30: Powertrain Chart 5 Diagnostic Flow Chart, MIL On (No Codes Present) Courtesy of General Motors Corp. POWERTRAIN CHART 6, MULTIPLE PCM CODES

Some powertrain components share common feeds and returns. Certain failures of these circuits will cause multiple codes to set. Flow chart indicates groups of codes set by failure of common feeds and/or returns. If all codes in a group are set, perform diagnosis listed in that box. If all codes in a group are not set, diagnose lowest code number first. G - TESTS W/CODES - 4.6LArticle Text (p. 50)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921 NOTE: Test numbers refer to numbers on diagnostic chart. 1) Circuit No. 474 is 5-volt feed from PCM to MAP sensor, TP sensor, EGR valve and BBV sensor. An open or short to ground in circuit No. 474 between PCM terminal 3E16 and circuit S235 will cause Codes P022, P032, P036 and P103 to set. 2) Circuit No. 452 is sensor return to PCM from IAT and MAP sensors. An open in circuit No. 452 between circuits S237 and S138 will cause Codes P031 and P038 to set. 3) Circuit No. 452 is sensor return to PCM from IAT sensor, MAP sensor and transaxle temperature sensor. An open in circuit No.

452 between circuit S237 and PCM terminal 2D1 will cause Codes P031, P038 and P059 to set. 4) Circuit No. 808 is sensor return to PCM from EGR valve, ECT sensor, BBV sensor and TP sensor. An open in circuit No. 808 and S236 and PCM will cause Codes P015, P021, P036 and P102 to set. 5) Circuit No. 741 is battery feed from fuse D1 (engine compartment fuse block) to transaxle solenoids "A" and "B". An open in circuit No. 741 will cause Codes P029, P094 and P117 to set. 6) Circuit No. 741 is battery feed from fuse D1 (engine compartment fuse block) to TCC brake switch which feeds the TCC through circuit No. 420. An open in circuits No. 741 and 420 or an open in TCC contacts of TCC brake switch will cause Codes P039 and P090 to set. 7) Circuit No. 741 is battery feed for transaxle shift solenoids "A" and "B", TCC brake switch and TCC. A short to ground on circuit No. 741, an open fuse D1 or an open feed to fuse D1 will cause Codes P029, P039, P090, P094 and P117 to set.

Fig. 31: Powertrain Chart 6 Schematic, Multiple PCM Codes Courtesy of General Motors Corp.

G - TESTS W/CODE

G - TESTS W/CODES - 4.6LArticle Text (p. 52)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921 Fig. 32: Powertrain Chart 6 Diagnostic Flow Chart, Multiple PCM Codes Courtesy of General Motors Corp.

POWERTRAIN CHART 7, REAR OXYGEN SENSOR DIAGNOSIS

PCM provides .45-volt reference signal to oxygen sensor on circuit No. 1670. When warm, a properly operating oxygen sensor will drive .45-volt reference signal lower, indicating a lean mixture or higher, indicating a rich mixture. This signal will toggle from rich to lean rapidly, at least one toggle every 2 seconds, if PCM is in good control of air/fuel mixture. This chart is designed to be used after oxygen sensor circuit and PCM operation have been verified through POWERTRAIN CHART 1, POWERTRAIN SYSTEM CHECK and PCM diagnostic trouble code diagnosis. This chart should identify oxygen sensors that are open (not able to drive .45-volt reference signal) or shorted (sensor output is fixed high or low, due to contaminants or internal sensor faults). NOTE:

Test numbers refer to numbers on diagnostic chart.

1) With engine running and coolant at normal operating temperature (85øC or greater) and at fast idle, observe engine data parameter PD33. Voltage should swing from less than .3 volt to greater than .6 volt. 2) With engine at fast idle, observe open/closed loop status light (AUTO indicator on CCC). If PCM switches system into closed loop operation, oxygen sensor is okay. If PCM remains in open loop operation and coolant temperature PD04 is greater than 185øF (85øC), replace oxygen sensor. 3) If voltage remains .3-.6 volt for a minimum of one minute, replace oxygen sensor and check cause of sensor contamination. 4) If there is no high voltage variation, check for intermittent sensor terminal contact or faulty sensor.

G - TESTS W/CODES - 4.6LArticle Text (p. 53)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 33: Powertrain Chart 7 Schematic, Rear Oxygen Sensor Diagnosis Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 54)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

G - TESTS W/CODES - 4.6LArticle Text (p. 55)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 34: Powertrain Chart 7 Diag. Flow Chart, Rear O2 Sensor Diagnosis Courtesy of General Motors Corp. POWERTRAIN CHART 8, FRONT OXYGEN SENSOR DIAGNOSIS

PCM provides .45-volt reference signal to oxygen sensor on circuit No. 412. When warm, a properly operating oxygen sensor will drive .45-volt reference signal lower, indicating a lean mixture or higher, indicating a rich mixture. This signal will toggle from rich to lean rapidly, at least one toggle every 2 seconds, if PCM is in good control of air/fuel mixture. This chart is designed to be used after oxygen sensor circuit and PCM operation have been verified through POWERTRAIN CHART 1, POWERTRAIN SYSTEM CHECK and PCM diagnostic trouble code diagnosis. This chart should identify oxygen sensors that are open (not able to drive .45-volt reference signal) or shorted (sensor output is fixed high or low, due to contaminants or internal sensor faults).

NOTE:

Test numbers refer to numbers on diagnostic chart.

1) With engine running and coolant at normal operating temperature (85øC or greater) and at fast idle, observe engine data parameter PD32. Voltage should swing from less than .3 volt to greater than .6 volt. 2) With engine at fast idle, observe open/closed loop status light (AUTO indicator on CCC). If PCM switches system into closed loop operation, oxygen sensor is okay. If PCM remains in open loop operation and coolant temperature PD04 is greater than 185øF (85øC), replace oxygen sensor. 3) If voltage remains .3-.6 volt for a minimum of one minute, replace oxygen sensor and check for cause of sensor contamination. 4) If there is no voltage variation, check sensor for intermittent terminal contact or faulty sensor.

Fig. 35: Powertrain Chart 8 Schematic, Front Oxygen Sensor Diagnosis Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 56)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 36: Powertrain Chart 8 Diag. Flow Chart, Front O2 Sensor Diagnosis Courtesy of General Motors Corp. PCM CODE CHARTS CODE P012, NO 4X REFERENCE SIGNAL FROM IGN CONTROL MODULE

PCM checks for cam pulses being received without 4X reference pulses. If PCM senses no reference pulses, engine will not start because fuel delivery system is triggered by pulses and Code P012 is set. Engine will start and run after an extended crank with Code P012 set. This is because the 24X reference pulses are being received by PCM. PCM uses this signal for fuel control instead. G - TESTS W/CODES - 4.6LArticle Text (p. 57)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921 Test Conditions Codes P035 and P041 not set. Code P012 is tested anytime cam sensor signals are being received during engine cranking operation.

Failure Conditions If PCM does not receive 4X reference pulses for 4 seconds while receiving cam reference pulses, Code P012 will set. Action PCM turns on Malfunction Indicator Light (MIL). NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks to see if Code P035 is present because a REF LO problem can cause other ignition problems. 2) If Code P012 is current, the condition still exists and can be diagnosed directly. If Code P012 is history, look at snapshot data to determine conditions under which code was set. 3) Check for proper output of electronic ignition system. If voltmeter reads 4.1 volts or greater, ignition control module is able to produce 4X reference pulses. 4) Checks to see if Code P012 was set while vehicle was running or not, if MAP value is 80 kPa or less, or if engine was running when code was set. Stray cam pulses with ignition on, engine not running can also cause a false Code P012 to set. 5) Checks for 4X reference pulses on circuit No. 430 from ignition control module to PCM. If PCM terminal No. 3E2 has been between 30-100 Hertz, PCM is receiving 4X receiving pulses. 6) Checks if a faulty PCM is pulling the 4X signal low. 7) Checks for short to voltage on circuit No. 430. 8) Checks if ICM is providing proper reference signal to PCM.

Fig. 37: Code P012 Schematic, No 4X Reference Signal From IGN Control Module G - TESTS W/CODES - 4.6LArticle Text (p. 58)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921 Courtesy of General Motors Corp

Fig. 38: Code P012 Diagnostic Flow Chart, No 4X Reference Signal From IGN Control Module Courtesy of General Motors Corp G - TESTS W/CODES - 4.6LArticle Text (p. 59)1995 Cadillac Concours

CODE P013, REAR HEATED OXYGEN SENSOR NOT READY

PCM provides .45-volt reference signal to oxygen sensor on circuit No. 1670. When oxygen sensor reaches operating temperature, it will generate a counter voltage that will vary based on amount of oxygen in exhaust. Rear oxygen sensor is located in manifold, before catalytic converter. A lean exhaust will generate a low voltage and cause .45-volt reference signal to decrease. A rich exhaust will generate a higher voltage and cause .45-volt reference signal to increase. Code P013 will set when oxygen sensor cannot respond under test conditions and generate a voltage greater or less than .45-volt reference. Code P013 will also set under following conditions: 1) Open in circuit No. 1670 or 1671. 2) Short to voltage on circuit No. 1670 or 1671. 3) Faulty oxygen sensor. Test Conditions Codes P014, P015, P021, P022, P026 and P027 are not set. Coolant temperature greater than or equal to 180øF (82øC). TP sensor value of 5-25 degrees. Throttle switch open. RPM 800 or greater. Failure Conditions Oxygen sensor voltage stays .307-.609 volt for more than 64 seconds (not toggling). Action PCM turns on MIL and closed loop is disabled. PCM enables canister purge solenoid if Code P017 is set. NOTE:

Test numbers refer to numbers on diagnostic chart. See POWERTRAIN CHARTS for references to CHART 7.

1) Voltage on PCM data parameter PD33 should fluctuate from less than 0.3 volt to greater than 0.6 volt. If voltage remain greater than 0.6 volt, check circuit No. 1670 for short to voltage. If voltage remains less than 0.3 volt, check circuit No. 1670 for short to ground. 2) Measuring voltage using voltmeter will isolate sensor/wiring problem from a PCM problem. If voltage fluctuates at greater than 0.6 volt and less than 0.3 volt, fault is with PCM. If voltage remains less than 0.3 volt, check circuit No. 1670 for short to ground or circuit No. 1671 for short to voltage. If voltage remains greater than 0.6 volt, check circuit No. 1670 for short to voltage. If voltage remains 0.3-0.6 volt, check circuits No. 1670 and 1671 for an open.

G - TESTS W/CODES - 4.6LArticle Text (p. 60)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 39: Code P013 Schematic, Rear Heated Oxygen Sensor Not Ready Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 61)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

G - TESTS W/CODES - 4.6LArticle Text (p. 62)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 40: Code P013 Diagnostic Flow Chart, Rear Heated Oxygen Sensor Not Ready Courtesy of General Motors Corp CODE P014, SHORTED ECT SENSOR SIGNAL

Engine coolant temperature sensor is located on thermostat

housing. ECT signal is on circuit No. 410. Sensor ground is on circuit No. 808. As sensor temperature increases, resistance decreases. A high coolant temperature will result in low signal voltage on circuit No. 410. Code P014 sets because engine coolant temperature cannot be greater than 296øF (147øC) when intake air temperature is less than 212øF (100øC). Test Conditions Codes P037 and P038 are not set and intake air temperature sensor value is less than or equal to 212øF (100øC). Failure Conditions Coolant sensor value greater than or equal to 298øF (148øC) for 2 seconds. Action PCM turns on MIL and uses IAT sensor value instead of coolant sensor value for all calculations during first 10 minutes of operation; it then uses a value of 194øF (90øC). Transaxle shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) With ECT sensor or wiring shorted, PCM parameter PD04 should indicate 148øC or greater. If PD04 does not indicate 148øC or greater, sensor or wiring is not shorted. 2) Checks for shorted sensor or circuit No. 410. If parameter value stays at 147øC or greater with sensor unplugged, short is in circuit No. 410 between terminal "B" and PCM terminal 1B5. 3) Check PCM connector. Fault is most likely at PCM connector or PCM.

G - TESTS W/CODE

Fig. 41: Code P014 Schematic, Shorted ECT Sensor Signal Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 64)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 42: Code P014 Diagnostic Flow Chart, Shorted ECT Sensor Signal Courtesy of General Motors Corp

CODE P015, OPEN ECT SENSOR SIGNAL

Engine coolant temperature sensor is a 2-wire thermistor, whose resistance varies with temperature. Sensor signal is on circuit No. 410. Sensor ground is on circuit No. 476. As sensor temperature increases, sensor resistance decreases. High coolant temperature will result in low signal voltage on circuit No. 410. Code P015 sets because PCM assumes coolant temperature cannot be -20øF (-29øC) or less when IAT is -9.4øF (-23øC) or greater. Test Conditions Codes P037 and P038 not set and IAT sensor value greater than or equal to -9.4øF (-23øC). Failure Conditions ECT sensor value is -20øF (-29øC) or less for 2 seconds. Action PCM turns on MIL and uses IAT sensor value instead of ECT sensor value for all calculations during first 5 minutes of operation. After 5 minutes, PCM uses a value of 194øF (90øC). Transaxle shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If sensor or wiring is open, parameter PD04 should indicate -29øC or less. 2) This checks for open sensor signal in circuit No. 410 from PCM to sensor connector. If parameter PD04 indicates 135-151øC with connector shorted, circuits No. 410 and 808 are okay. 3) Checks for open in circuit No. 808 from sensor terminal "A" to ground splice. If shorting terminal "A" to ground causes parameter PD04 to indicate 135-151øC, an open in circuit No. 808 exists. 4) This checks if PCM can recognize a short to ground or low voltage on terminal 1B5, coolant temperature signal. If grounding terminal 1B5 causes PD04 to indicate 135-151øC, circuit No. 410 from PCM to ECT sensor is open.

G - TESTS W/CODES - 4.6LArticle Text (p. 65)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 43: Code P015 Schematic, Open ECT Sensor Signal Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 66)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

G - TESTS W/CODES - 4.6LArticle Text (p. 67)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 44: Code P015 Diagnostic Flow Chart, Open ECT Sensor Signal Courtesy of General Motors Corp CODE P016, ALTERNATOR VOLTAGE OUT OF RANGE

PCM monitors ignition feed voltage on circuit No. 539 to PCM. Code P016 sets when system voltage drops to less than 10 volts or increases to greater than 16 volts with engine running at greater than 500 RPM. If ignition voltage goes to zero volts (open circuit), engine will not run since PCM does not have ignition signal. Test Conditions Tested continuously. Failure Conditions Engine speed at 500 RPM or greater. Ignition voltage to PCM less than 10 volts or more than 16 volts for 5.0 seconds.

Action PCM turns on MIL. PCM turns off canister purge solenoid, disables cruise control, de-energizes TCC solenoid and disables transaxle pressure control solenoid. PCM allows only 2nd gear operation when any forward gear is selected. Transaxle shifts adapts are maintained at current level. Garage shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) This checks voltages are within 0.5 exist. If not, find out 2) This checks voltage.

PCM data for parameters PD15 and ID50. If volts of each other, a system problem may why PCM is different. if PCM data PD15 is actually displaying system

Note On Intermittents A loose or faulty alternator terminal "L" connector may cause Code P016 to set intermittently.

Fig. 45: Code P016 Schematic, Alternator Voltage Out Of Range Courtesy of General MotorsText Corp G - TESTS W/CODES - 4.6LArticle (p. 68)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 46: Code P016 Diagnostic Flow Chart, Alternator Voltage Out Of Range Courtesy of General Motors Corp CODE P017, FRONT OXYGEN SENSOR NOT READY

PCM provides a .45-volt reference signal to oxygen sensor on circuit No. 412. When warm, a properly operating oxygen sensor will provide PCM .45-volt reference signal lower (less than .45 volt) to indicate a lean mixture and higher (greater than .45 volt) to indicate a rich mixture. If oxygen sensor does not vary from cold or not-ready voltage under test conditions, PCM assumes sensor cannot respond to air/fuel mixture changes and sets a Code P017. Possible causes of Code P017 are: * * *

Open in circuits No. 412 or 413. Short to voltage on circuit No. 412 or 413. Oxygen sensor cannot respond.

Test Conditions Codes P014, P015, P021, P022, P026 and P027 not set. Coolant temperature greater than or equal to 180øF (82øC). TP sensor value 525 degrees. Throttle switch open and engine speed 800 RPM or greater. Failure Conditions Oxygen sensor voltage stays .307-.609 volt for more than 64 seconds (not toggling).

Action PCM turns on MIL. PCM enables canister purge solenoid if Code G - TESTS W/CODES - 4.6LArticle Text (p. 69)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

P013 is also set. Closed loop operation is disabled. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Voltage on PCM data parameter PD32 should fluctuate from greater than 0.6 volt to less than 0.3 volt. If voltage remains at greater than 0.6 volt, check circuit No. 412 for a short to voltage. If voltage remains at less than 0.3 volt, check circuit No. 412 for a short to ground. 2) Measuring voltage using a voltmeter will isolate a sensor/wiring problem from a PCM problem. If voltage fluctuates at greater than 0.6 volt and less than 0.3 volt, PCM is faulty. If voltage remains at less than 0.3 volt, check circuit No. 412 for a short to ground or circuit No. 413 for a short to voltage. If voltage remains greater than 0.6 volt, check circuit No. 412 for short to voltage. If voltage remains 0.3-0.6 volt, check circuits No. 412 and 413 for an open.

Fig. 47: Code P017 Schematic, Front Oxygen Sensor Not Ready Courtesy of General Motors Corp

G - TESTS W/CO

Fig. 48: Code P017 Diagnostic Flow Chart, Front Oxygen Sensor Not G - TESTS W/CODES - 4.6LArticle Text (p. 71)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921 Ready Courtesy of General Motors Corp CODE P019, SHORTED FUEL PUMP FEEDBACK SIGNAL

PCM monitors fuel pump feedback voltage for 6 seconds after ignition is turned on without engine being cranked. Fuel pump relay will be energized for 2 seconds and then de-energized. If voltage on fuel pump feedback does not drop to less than 7 volts during first 4 seconds after ignition is turned on (engine off), Code P019 will set, indicating voltage on circuit No. 120 with fuel pump relay deenergized. Test Conditions Codes P012, P014 and P015 not set. Coolant temperature at 122øF (50øC) or greater. No 4X reference pulses detected since ignition was turned on (engine not cranked). Failure Conditions Fuel pump feedback voltage remains greater than or equal to 7 volts for 6 seconds (fuel pump relay never de-energized). Action PCM turns on SERVICE VEHICLE SOON message. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) With ignition on, engine off, fuel pump should not be running and fuel pump feedback (PCM parameter PD10) should be zero volts. If PD10 shows voltage greater than 7 volts, repair circuit No. 120. 2) This checks for shorted oil pressure switch. 3) This checks for shorted fuel pump relay. 4) This checks for voltage on circuit No. 120 at PCM. 5) This checks for proper control of fuel pump relay by PCM. Note On Intermittents Probe fuel pump test point using a voltmeter to ground. Turn ignition on, and observe voltmeter. Voltmeter should indicate battery voltage for 2 seconds and then drop to zero. If voltage reading stays at battery voltage for longer than 2 seconds, check for sticking fuel pump relay contacts. Repeat test several times. Continue probing fuel pump test point to ground. Start engine, and then turn it off. Voltage should immediately drop to zero. If voltage does not immediately drop to zero, check oil pressure switch contacts.

G - TESTS W/CODES - 4.6LArticle Text (p. 72)1995 Cadillac

Fig. 49: Code P019 Schematic, Shorted Fuel Pump Feedback Signal Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 73)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

G - TESTS W/CODES - 4.6LArticle Text (p. 74)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 50: Code P019 Diagnostic Flow Chart, Shorted Fuel Pump Feedback Signal Courtesy of General Motors Corp CODE P020, OPEN FUEL PUMP CIRCUIT

Fuel pump receives power from circuit No. 120 through either the fuel pump relay or oil pressure switch. PCM energizes fuel pump relay for 2 seconds after key is turned on. Fuel pump is then turned off if no 4X reference pulses are received. The oil pressure switch is provided as a backup to fuel pump relay enabling engine to start when

fuel pump relay fails. Code P020 is set when PCM sees fuel pump is not energized (zero volts on feedback circuit) with engine cranking or running. PCM code is designed to detect a fuel pump relay fault (relay not powering fuel pump). Test Conditions Engine speed greater than or equal to 24 RPM. Failure Conditions Fuel pump feedback voltage less than or equal to 2 volts for 1.3 seconds or more. Action PCM turns on SERVICE VEHICLE SOON light. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks for engine to start with fuel pump powered through fuel pump relay. If engine does not start, proceed to CODE P020 (2 OF 3). 2) Checks circuit No. 120 for open or if no fault code is present. 3) Checks for open in circuit No. 239 from fuse to fuel pump relay terminal No. 5. 4) Checks for open in circuit No. 50 to fuel pump relay terminal No. 5. 5) Checks if fuel pump will run to isolate a fuel pump control problem from a fuel pump problem. 6) If greater than or equal to 10 volts is measured, fuel pump relay circuit is okay. Fuel pump relay is faulty. 7) Checks for open in circuit No. 120 from fuel pump relay to fuel pump. 8) Checks for proper control of fuel pump relay by PCM. 9) Checks for an open in circuit No. 1250 (fuel pump ground). 10) Checks circuit No. 239 for short to ground. 11) Isolates when circuit No. 120 is shorted to ground. 12) Checks circuit No. 120 for short to ground between oil pressure switch and PCM. 13) Checks fuel pump harness for short to ground. If harness is okay, check circuit No. 120 from fuel pump relay terminal No. 3 for short to ground.

G - TESTS W/CO

Fig. 51: Code P020 Schematic, Open Fuel Pump Circuit Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 76)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 52: Code P020 Diagnostic Flow Chart - 1 Of 3, Open Fuel Pump Circuit Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 77)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

G - TESTS W/CODES - 4.6LArticle Text (p. 78)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 53: Code P020 Diagnostic Flow Chart - 2 Of 3, Open Fuel Pump Circuit Courtesy of General Motors Corp

Fig. 54: Code P020 Diagnostic Flow Chart - 3 Of 3, Open Fuel Pump Circuit Courtesy of General Motors Corp CODE P021, SHORTED TP SENSOR CIRCUIT (SIGNAL VOLTAGE HIGH)

Throttle Position (TP) sensor is a potentiometer. A 5-volt reference is provided on circuit No. 474 and ground is provided on circuit No. 808. TP sensor signal circuit No. 417 varies between zero and 5 volts based on throttle plate position. At low throttle angle, TP sensor signal voltage is low. PCM uses TP sensor information to determine idle, WOT, deceleration leanness and acceleration enrichment. Code P021 sets when PCM detects a TP sensor signal that is too high. Test Conditions

G - TESTS W/CODES - 4.6LArticle Text (p. 79)1995 Cadillac Concours

Engine speed 25-3000 RPM. Failure Conditions TP sensor value greater than or equal to 85 degrees for 0.1 second. Action PCM turns on MIL, disables TCC and transaxle pressure control. PCM sets TP sensor equal to 13 degrees when TP sensor is open and 6 degrees when TP sensor is closed. PCM freezes transaxle in current gear. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If TP sensor or wiring is shorted, data parameter PD01 will read 85 or greater. 2) Checks for shorted TP sensor or wiring. If data value stays greater than -7 with TP sensor disconnected, check for problem in wiring. 3) Check for open in circuit No. 808 between TP sensor and PCM. An open in circuit No. 808 will result in high TP sensor signal whenever TP sensor is connected.

Fig. 55: Code P021 Schematic, Shorted TP Sensor Circuit (Signal Voltage High) G - TESTS Courtesy of General Motors Corp W/CODES - 4.6LArticle Text (p. 80)1995 Cadillac ConcoursFor Ace Mecha

Fig. 56: Code P021 Diagnostic Flow Chart, Shorted TP Sensor Circuit (Signal Voltage High) Courtesy of General Motors Corp CODE P022, OPEN TP SENSOR CIRCUIT (SIGNAL VOLTAGE LOW)

TP sensor is a potentiometer. A 5-volt reference is provided on circuit No. 474 and ground is provided on circuit No. 808. TP sensor signal circuit No. 417 varies between zero and 5 volts based on throttle plate position. At low throttle angle, TP sensor signal voltage is low. PCM uses TP sensor information to determine idle, WOT, deceleration leanness and acceleration enrichment. Code P022 sets when PCM detects a TP sensor signal that is too low. Test Conditions Engine speed at least 600 RPM. Failure Conditions TP sensor value less than -5 degrees for one second. Action

G - TESTS W/CODES - 4.6LArticle Text (p. 81)1995 Cadillac Concours

PCM turns on MIL and disables TCC. PCM sets TP sensor equal to 13 degrees when throttle switch is open and 6 degrees when throttle switch is closed. PCM freezes transaxle in current gear. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If Code P032, P036 and P103 are also present, check circuit No. 474 for open or short to ground. TP sensor and MAP sensor share 5-volt reference signal. 2) With TP sensor or wiring open, PCM data parameter PD01 will read -5 or less. 3) Checks for open TP sensor or circuit. If data value stays less than 85 with TP sensor terminals "A" and "C" jumpered together, problem is in wiring. 4) Voltage should be greater than 0.5 volt if circuit No. 474 is not open or shorted to ground. 5) Checks to see if circuit No. 474 is open or if circuit No. 417 is shorted to ground. 6) Checks if signal is reaching PCM. If signal is reaching PCM, fault is in PCM.

Fig. 57: Code P022 Schematic, Open TP Sensor Circuit (Signal Voltage Low) Courtesy of General Motors Corp G - TESTS W/CODES - 4.6LArticle Text (p. 82)1995 Cadillac ConcoursFor Ace Mechanics 123 Main

Fig. 58: Code P022 Diagnostic Flow Chart, Open TP Sensor Circuit (Signal Voltage Low) Courtesy of General Motors Corp CODE P023, IGNITION CONTROL CIRCUIT PROBLEM

Test Conditions (Crank) By-pass line low (zero volts) and at least 2 reference pulses have been received by PCM. Failure Conditions (Crank) No ignition pulses detected in circuit No. 423.

Test Conditions G - TESTS W/CODES - 4.6LArticle(Run) Text (p. 83)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921 By-pass line high (5 volts) and at least 2 reference pulses

have been received by PCM. Failure Conditions (Run) No ignition control pulses detected on circuit No. 423. Action PCM turns on MIL and will not enable spark timing control. Engine will start and run on base timing. PCM disables EGR solenoid. Transaxle shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if Code P035 is set. A REF LO problem can cause other ignition problems. 2) Checks if Code P023 was set during engine crank or while engine was running. 3) Checks for short to voltage on circuit No. 424. Checks if PCM failure is causing ignition control system into by-pass spark control when it should not be. 4) Checks for open in circuit No. 423 to see if ignition control pulses are reaching ignition control module or if pulses are reaching ignition control module but ignition control module is not reacting. 5) Checks for short to voltage in circuit No. 424. 6) Checks if by-pass control is being sent by PCM to ignition control module. If by-pass control is being sent, voltage will be greater than 4.1 volts. 7) Checks if by-pass control being sent by PCM is being received by ignition control module. If circuit No. 424 is good, resistance will be less than 5 ohms. 8) Checks if PCM is providing proper signal to ICM. If PCM terminal 3F3 has 30-100 Hertz, PCM is not at fault. 9) Checks if PCM can produce proper ignition control pulses. If maximum voltage exceeds 3.7 volts, PCM is okay and ICM is at fault. 10) Checks circuit No. 424 for short to ground. 11) Checks if ICM is able to recognize a by-pass signal. If it does, Code P023 will not set again. If Code P023 resets, the ICM is faulty. If does not reset, PCM is faulty. 12) Checks if ICM is causing incorrect voltage or if PCM is supplying incorrect signal.

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Fig. 59: Code P023 Schematic, Ignition Control Circuit Problem Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 85)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

G - TESTS W/CODES - 4.6LArticle Text (p. 86)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 60: Code P023 Diagnostic Flow Chart - 1 Of 2, Ignition Control Circuit Problem Courtesy of General Motors Corp

Fig. 61: Code P023 Flow Chart - 2 Of 2, Ignition Control Circuit Problem Courtesy of General Motors CorpG - TESTS W/CODES - 4.6LArticle Text (p. 87)1995 Cadillac Concours

CODE P024, VEHICLE SPEED SENSOR (VSS) CIRCUIT PROBLEM

VSS is a permanent magnet pulse generator mounted in transaxle. PCM receives unbuffered speed information VSS. Code P024 sets if PCM detects vehicle speed of 5 MPH or less with transaxle input speed (turbine speed) of 3000 RPM or greater for one second while in any forward gear. To avoid any erratic cruise control operation due to an intermittent problem, cruise control system is disabled for the entire ignition cycle. Test Conditions Codes P056 and P091 not set. Transaxle in Park or Neutral. Transaxle pressure switch indicating not in Reverse. Transaxle input speed sensor indicating 3000 RPM or greater. Failure Conditions Vehicle speed at 5 MPH or less for one second. Action PCM turns on MIL and disables Torque Converter Clutch (TCC) and cruise control for the entire ignition cycle. PCM will substitute a calculated vehicle speed based on transaxle input speed and the current gear commanded (gear ratio). PCM freezes transaxle in current gear and torque management is disabled. NOTE:

Test number refers to number on diagnostic chart.

1) If Code P025 is current, fault is present and can be diagnosed directly. If Code P025 is stored as history, refer to Code P075 to diagnose fault. 2) VSS will generate a frequency of greater than zero Hertz when spun by hand. If it does, PCM is faulty. If it does not, check circuit or sensor for open or short. Note On Intermittents Check for Electromagnetic Interference (EMI) induced on circuits No. 400 and 401 by running them close to spark plug wires or high power transmitters (mobile radios) operating in vicinity.

G - TESTS W/CODES - 4.6LArticle Text (p. 88)1995 Cadillac Concours

Fig. 62: Code P024 Schematic, VSS Circuit Problem Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 89)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

G - TESTS W/CODES - 4.6LArticle Text (p. 90)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 63: Code P024 Diagnostic Flow Chart, VSS Circuit Problem Courtesy of General Motors Corp CODE P025, 24X REFERENCE SIGNAL LOW

PCM checks for 4X reference pulses being received without 24X reference pulses. Code P025 is set when engine is running and PCM is receiving 4X reference pulses and 24X reference signal line is low for 4 seconds. Test Conditions Codes P035 and P041 are not set. A cam reference pulse was received and engine speed at greater than 496 RPM but less than 1200 RPM. Ignition control not in by-pass mode.

Failure Conditions No 24X reference pulses received by PCM and the line is low for 4 seconds. Action PCM turns on SERVICE VEHICLE SOON light message. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks to see if Code P035 is present because REF LO problem can cause other ignition problems. 2) Checks ability of ignition control module to produce 24X reference pulses. If system is operating correctly, reading will be 200 Hertz or greater. 3) Checks to see if ICM is providing PCM the proper 24X reference signal. 4) Checks for open or short to ground in circuit No. 647.

Fig. 64: Code P025 Schematic, 24X Reference Signal Low Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 91)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 65: Code P025 Diagnostic Flow Chart, 24X Reference Signal Low Courtesy of General Motors Corp CODE P026, SHORTED THROTTLE POSITION SWITCH CIRCUIT

Throttle position switch is part of ISC motor assembly. PCM provides a 5-volt reference signal on circuit No. 427. When throttle lever contacts ISC plunger, throttle switch closes. When throttle switch is closed, input voltage is low. Code P026 sets when PCM sees a TP sensor signal greater than 16 degrees (accelerator applied) but throttle switch remains closed.

Test Conditions 1995 and Cadillac ConcoursForangle Ace Mechanics 123 Main Street San Diego Ca 921 G - TESTS W/CODES - 4.6LArticle Text not (p. 92)set Codes P021 and P022 throttle is 16-85 degrees. Failure Conditions Throttle switch input to PCM closed for 1.8 seconds.

Action PCM turns on MIL, disables EGR and assumes throttle switch is closed if brakes are applied or if TP sensor position is less than or equal to 18 degrees. PCM also assumes open throttle when brakes are off or TP sensor position is greater than 18 degrees. Garage shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) PCM input PI72 should cycle from LO to HI to LO when accelerator is depressed and released. 2) If PCM input PI72 changes to HI when ISC motor is disconnected, fault is with ISC motor. If PI72 still stays LO, check circuit No. 427 for short to ground. 3) Checks if circuit No. 427 is shorted to ground or if PCM is faulty.

Fig. 66: Code P026 Schematic, Shorted Throttle Position Switch Circuit Courtesy of General Motors Corp

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Fig. 67: Code P026 Diagnostic Flow Chart, Shorted Throttle Position Switch Circuit Courtesy of General Motors Corp CODE P027, OPEN THROTTLE POSITION SWITCH SIGNAL

Diagnostic test monitors ISC throttle position switch during some coast down and idle conditions with throttle position switch open and brake applied. Under these conditions, PCM commands ISC to retract, and monitors TP sensor for corresponding decrease in throttle position. PCM sets Code P027 if it detects a decrease in throttle position 2 times in succession, throttle is resting on ISC plunger and throttle position should be closed.

Test Conditions Codes P021, P022 and P024 not set. Vehicle in coast down condition. Throttle switch open, brakes applied, throttle angle 12 degrees or less and engine speed at least 64 RPM greater than desired. At least 20 seconds have passed between brake applications or the last ISC motor pulse from PCM. Text (p. 94)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921 G - TESTS W/CODES - 4.6LArticle Failure Conditions PCM retracts ISC motor and sees a corresponding decrease in throttle angle twice.

Action PCM turns on MIL. EGR is disabled. Garage shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) LO fan status light should cycle from ON to OFF to ON when accelerator is depressed and released. 2) Checks if fault is with throttle position switch. 3) Checks PCM's ability to recognize signal if circuit No. 427 is open. 4) Checks if circuit No. 451 is open. Note On Intermittents Code P027 may set if TCC brake switch is sticking open or if accelerator and brake pedals are depressed simultaneously. Refer to input test PI71 to verify proper switch function.

Fig. 68: Code P027 Schematic, Open Throttle Position Switch Signal Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 95)1995 Cadillac ConcoursFor Ace Mechanics

Fig. 69: Code P027 Diagnostic Flow Chart, Open Throttle Position Switch Signal Courtesy of General Motors Corp CODE P028, TRANSAXLE PRESSURE SWITCH/CIRCUIT PROBLEM

PCM checks for illegal transaxle pressure switch inputs (000 & 010) in addition of any of following failure conditions: *

Transaxle range switch indicating no in P/N position but transaxle pressure switch input to PCM indicating P/N (101) with a valid drive transaxle gear ratio (3.11 or less). * Transaxle pressure switch input to PCM indicating REV (100) with a gear ratio not within recognized reverse gear ratio range (gear ratio less than or equal to 2.02 or gear ratio Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921 G - TESTS W/CODES 4.6LArticle Text (p.to 96)1995 greater - than or equal 2.23). * Transaxle pressure switch input to PCM indicating D1 (110), D2 (111), D3 (011) or D4 (001) with a reverse gear ratio (gear ratio between 2.02 and 2.23).

If any of above conditions are met for 5 seconds, Code P028 will set for the entire ignition cycle. Test Conditions 1 Engine running. Failure Conditions 1 Illegal transaxle pressure switch value (000 and 010). Test Conditions 2 Codes P021, P022, P024, P056, P056, P075, P086 and P091 not set. Engine running. Vehicle speed at 7 MPH or greater and throttle angle at 15.7 degrees or greater. Failure Conditions 2 Transaxle switch indicating not in Park or Neutral, but transaxle pressure switch value at 101 (P/N) with gear ratio of 3.11 or less or 5 seconds. Transaxle pressure switch value 100 (REV) with gear ratio of 2.02 or 2.23 for 5 seconds. Transaxle pressure switch value 001 (D4), 011 (D3), 111 (D2) or 110 (D1) with gear ratio of 2. 02-2.23 for 5 seconds. Action PCM turns on MIL. PCM will substitute previous transaxle switch value if it is consistent with transaxle range switch. If not, PCM will substitute D4 for transaxle switch value if transaxle range switch indicates Drive/Reverse and Park/Neutral if transaxle range switch indicates Park/Neutral. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks PCM data PD71 for failure that is present in all transaxle ranges ("1" is for open circuit and "0" for short to ground). 2) Determines in which circuit the failure is present. 3) Checks if PCM is receiving correct voltage changing between zero and 12 volts and not recognizing it. 4) If voltage remains at zero volts, circuit is shorted to ground. If voltage remains at 12 volts, circuit is open. 5) Checks if short to ground is internal or external of transaxle. 6) If PCM data PD71 parameter values are as specified in Code P028 (1 of 2) diagnostic flow chart, problem is intermittent. If parameter values are not as specified, transaxle range switch is giving wrong readings. 7) Checks if failure occurred while vehicle was in Reverse or not. If gear ratio was 2.02-2.23, vehicle was in Reverse when failure occurred. G - TESTS W/CODES - 4.6LArticle Text (p. 97)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

8) Checks Code P028 snapshot data PD71 to determine exactly what transaxle pressure switch value was at when code was set to determine which circuits are open or shorted to ground.

Fig. 70: Code P028 Schematic, Transaxle Pressure Switch/Circuit Problem Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 98)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San

G - TESTS W/CODES - 4.6LArticle Text (p. 99)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 921

Fig. 71: Code P028 Diagnostic Flow Chart - 1 Of 2, Transaxle Pressure Switch/Circuit Problem Courtesy of General Motors Corp

Fig. 72: Code P028 Diagnostic Flow Chart - 2 Of 2, Transaxle Pressure Switch/Circuit Problem Courtesy of General Motors Corp CODE P029, TRANSAXLE SHIFT SOLENOID "B" PROBLEM

PCM monitors gear ratio and compares the ratio to the commanded gear ratio. Code PO29 will set if both ratios are not G - TESTS W/CODES - 4.6LArticle Text (p. 100)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 synchronized.

Test Conditions Codes P021, P022, P024, P028 and P056 not set. Transaxle pressure switch indicating D1, D2, D3 or D4 position. Engine running and vehicle speed at 7 MPH or greater. Throttle angle position at 11 degrees or greater.

* * * *

Failure Conditions: Case 1 - Gear ratio commanded. Case 2 - Gear ratio commanded. Case 3 - Gear ratio commanded. Case 4 - Gear ratio commanded.

0.65-0.71 for 5 seconds. 1st gear 0.95-1.05 for 5 seconds. 2nd gear 1.54-1.71 for 5 seconds. 3rd gear 2.87-3.11 for 5 seconds. 4th gear

Action PCM turns on MIL. PCM commands 2nd gear when any forward gear is selected and garage shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if Code P117 is set. 2) Checks if shift solenoid "B" is in high when it should be in low or vice-versa. 3) Checks if PCM is operating correctly but setting false codes. 4) Checks if circuit No. 741 is open. 5) Checks if circuit No. 1223 is open (engine harness side). 6) Checks for short to ground inside transaxle. 7) Checks for open circuit inside transaxle. 8) Checks circuit No. 1223 (transaxle harness side) for short to voltage inside transaxle. 9) Checks circuit No. 1223 (engine harness side) for short to voltage from PCM connector. 10) Possible causes of getting 4th gear when 1st gear is commanded. 11) Possible causes of getting 3rd gear when 2nd gear is commanded. 12) Possible causes of getting 2nd gear when 3rd gear is commanded. 13) Possible causes of getting 1st gear when 4th gear is commanded.

G - TESTS W/CODES - 4.6LArticle Text (p. 101)1995 Cadillac ConcoursFor Ace Mechanics 123 Main St

Fig. 73: Code P029 Schematic, Transaxle Shift Solenoid "B" Problem Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 102)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 103)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 74: Code P029 Diagnostic Flow Chart - 1 Of 2, Transaxle Shift Solenoid "B" Problem Courtesy of General Motors Corp

Fig. 75: Code P029 Diagnostic Flow Chart - 2 Of 2, Transaxle Shift Solenoid "B" Problem Courtesy of General Motors Corp CODE P030, ISC RPM OUT OF RANGE

1995 by Cadillac ConcoursFor Ace 123 Main Street San Diego Ca 92 G - TESTS W/CODES - 4.6LArticle Text idle (p. 104)RPM PCM controls engine increasing or Mechanics decreasing

throttle opening using Idle Speed Control (ISC) motor. ISC controls idle speed any time throttle switch is closed. Code P030 detects engine RPM out of limits. Test Conditions Codes P021, P022, P024, P026 and P027 not set, throttle switch closed, vehicle speed equals zero, battery voltage greater than or equal to 11 volts, desired engine speed 288 RPM greater than actual RPM, and idle speed control start-up delay over. Engine not receiving power steering load. PCM not commanding an idle speed anticipate. Failure Conditions ISC motor in forward mode. TP sensor at least 9.1 degrees or less and ISC extending for 64 seconds or ISC motor in reverse mode, TP sensor position at 1.3 degrees or greater and ISC retracting for 64 seconds. Action PCM turns on MIL. NOTE:

Test numbers refer to numbers on diagnostic chart. 1) This step checks for ISC motor codes that can cause other

problems. 2) This step checks if cruise control is engaged, causing idle problems. 3) Checks for proper ISC motor operation. 4) Many engine fuel and emissions system faults may cause unstable idle. If base engine idle is not steady, ISC may not be able to control idle to within 152 RPM of desired idle. For symptom diagnosis, see H - TESTS W/O CODES article in the ENGINE PERFORMANCE section. 5) This step checks PCM's ability to control ISC motor by checking for signal present at ISC motor. 6) This step checks for open or short to ground in circuit No. 425 or 426. 7) Checks PCM's ability to control ISC motor by checking for signal present at ISC motor. 8) Checks if ISC motor is receiving signal but not responding correctly. Voltage should fluctuate continuously from negative to positive value. Note On Intermittents This code may set due to an intermittently sticking ISC motor.

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Fig. 76: Code P030 Schematic, ISC RPM Out Of Range Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 106)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 107)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 77: Code P030 Diagnostic Flow Chart - 1 Of 2, ISC RPM Out Of Range Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 108)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 78: Code P030 Diagnostic Flow Chart - 2 Of 2, ISC RPM Out Of Range Courtesy of General Motors Corp CODE P031, SHORTED MAP SENSOR CIRCUIT

MAP sensor output signal voltage is a DC voltage varying with manifold pressure. PCM provides a 5-volt reference signal and ground.

MAP signal varies between zero and 5 volts as manifold pressure changes. As MAP decreases, voltage decreases (low engine load, high vacuum). As MAP increases, voltage increases (high engine load, low vacuum). PCM uses MAP sensor values to indicate engine load. A high MAP reading indicates heavy load and low MAP indicates low load. Code P031 is designed to set when PCM detects a MAP sensor signal out of high limits. Test Conditions Tested continuously. Codes P021 and P022 not set. Engine running with throttle angle at 20.5 degrees or less. Failure Conditions MAP value high for at least .25 second. Action PCM turns on MIL, disables long term fuel trim and uses a substitute MAP sensor value based on engine RPM and throttle switch status (open or closed). PCM disables torque management and transaxle shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If Code P038 is set, check circuit No. 452 for open or short to voltage. MAP and IAT sensors share this same circuit. 2) PD02 will read 103-105 kPa if MAP sensor or circuit is shorted. 3) If PCM data PD02 goes to 10-16 kPa with connector unplugged, check for faulty sensor or circuit. 4) Checks circuit No. 432 for short to battery. If circuit is okay, replace PCM. Note On Intermittents Code P031 could be set during an engine backfire, which cause a rapid increase in MAP value. Check Code P031 snapshot.

G - TESTS W/CO

Fig. 79: Code P031 Schematic, Shorted MAP Sensor Circuit Courtesy of General Motors Corp

G - TESTS W/CODES - 4.6LArticle Text (p. 110)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 111)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 80: Code P031 Diagnostic Flow Chart, Shorted MAP Sensor Circuit Courtesy of General Motors Corp CODE P032, OPEN MAP SENSOR CIRCUIT

MAP sensor changes resistance based upon manifold vacuum. PCM provides a 5-volt reference and ground. MAP signal varies between zero and 5 volts as manifold vacuum varies. Code P032 sets when PCM detects MAP sensor signal is too low. Test Conditions (1) Engine speed less than or equal to 700 RPM, throttle angle less than or equal to 18 degrees and TP sensor closed. Test Conditions (2) Engine speed less than or equal to 1800 RPM, throttle angle

less than or equal to 13 degrees, TP sensor open and transmission not in Park or Neutral. Failure Conditions MAP value less than 16 kPa for .2 second. Action PCM turns on MIL. PCM disables long term fuel trim and uses a substitute MAP value based on engine RPM and throttle switch status (open or closed). PCM disables EVAP control solenoid. PCM disables torque management and transaxle shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart. 1) PD02 will read 10-16 kPa if MAP sensor or related circuit

is open. 2) Checks for 5-volt reference signal at sensor connector. A reading of 103-105 kPa means that wiring and PCM are okay. 3) Checks circuit No. 432 for short to ground and circuits No. 432 and 474 and MAP sensor circuit for open. 4) Checks circuit No. 432 for short to ground. 5) Checks if 5-volt signal is reaching PCM. If signal is present, replace PCM.

Fig. 81: Code P032 Schematic, Open MAP Sensor Circuit Courtesy of General Motors Corp

G - TESTS W/COD

Fig. 82: Code P032 Diagnostic Flow Chart, Open MAP Sensor Circuit Courtesy of General Motors Corp CODE P033, EXTENDED TRAVEL BRAKE SWITCH INPUT CIRCUIT PROBLEM

This test assumes that a sudden decrease in non-drive (rear) wheel speed is caused by a brake application. Non-drive wheels and stoplight switch status are supplied to PCM through the serial data from the EBTCM.

Test Conditions Mechanics and 123 Main Codes P106 Text and (p. P137 not Cadillac set. ConcoursFor TractionAce control ABSStreet San Diego Ca 92 G - TESTS W/CODESP090, - 4.6LArticle 113)1995

systems operating normally and non-drive wheel speed of 36 MPH or greater. Failure Conditions A 2 MPH or greater decrease in non-drive wheel speed in 0.2 seconds. Transition in the TCC contacts of the TCC brake switch or stop/BTSI/cruise brake switch. No transition noticed in the extended travel contact of TCC brake switch. If these conditions are met and counter reaches 5, Code P033 sets. Action PCM disables cruise control and substitutes status of TCC contacts of TCC brake switch input for the extended travel input. PCM turns on SERVICE VEHICLE SOON light message. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) PCM input PI86 should cycle from high to low when brake pedal is depressed and then released. If PI86 remains low, check for open or short to ground in system. If PI86 remains high, check for short to voltage in system. 2) If 10 volts or greater is measured, check circuit No. 847 or TCC brake switch for open circuit. If less than 10 volts is measured, check circuits No. 341 and 847 for a short to ground.

Fig. 83: Code P033 Schematic, Extended Travel Brake Switch Input Circuit Problem Courtesy of General Motors Corp.

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Fig. 84: Code P033Diagnostic Flow Chart, Extended Travel Brake Switch Input Circuit Problem Courtesy of General Motors Corp. CODE P034, MAP SENSOR SIGNAL TOO HIGH

This test monitors MAP sensor signals for loss of engine vacuum under closed throttle condition. If difference between MAP signal and calculated BARO is 11 kPa or less for 15 seconds, Code P034 sets. G - TESTS W/CODES - 4.6LArticle Text (p. 115)1995 Cadillac Concours

Test Conditions Codes P021, P022, P026, P027, P031 and P032 not set, throttle switch closed, engine speed greater than or equal to 400 RPM, throttle angle less than or equal to 18 degrees and BARO at least 75 kPa. Failure Conditions Difference between MAP and calculated BARO sensor value 11 kPa or less for 15 seconds. Action PCM turns on MIL. PCM uses a substitute MAP sensor value based on engine RPM and throttle position switch status. PCM disables long term fuel trim. PCM disables EVAP canister solenoid. PCM disables torque management and transaxle shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) MAP at idle should be 30-50 kPa, depending on engine load. BARO pressure should be 85-105 kPa, depending upon altitude. 2) Check for vacuum at fuel pressure regulator hose. At idle, typical vacuum reading should be 14-20 in. Hg, depending on engine load. 3) PCM data PD02 should read 10-16 kPa MAP sensor connector disconnected. If PD02 reads greater than 16 kPa, check circuit No. 432 for short to voltage. 4) Checks for short to voltage inside intake manifold. 5) Checks for short to voltage on circuit No. 452 or 474. Also checks for high resistance on circuit No. 452. Ensure transaxle temperature sensor connector is disconnected to eliminate voltage. CODE P035, IGNITION GROUND VOLTAGE OUT OF RANGE

This test monitors the REF LO voltage (circuit No. 453) input to PCM and sets Code P035 if voltage difference between REF LO and PCM power ground is greater than preset values. PCM internally adds 2.5 volts to REF LO signal. If voltage is greater than 3.98 volts or less than 1.04 volts, PCM will set Code P035. Test Conditions Code P016 not set. Failure Voltage module REF LO is voltage is -1.46

Conditions difference between PCM ground and ignition control 1.48 volts or greater for one second or REF LO volts or less for one second.

G - TESTS W/CODES - 4.6LArticle Text (p. 116)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Action None. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If value of PD09 is 1.1 volts or less, PCM ground voltage is floating high, causing Code P035 to set. 2) Checks for short to voltage in circuit No. 453. 3) Voltage measured at ignition control module connector C4 terminal "F" should be less than 0.1 volt. If voltage is higher, check module for bad ground (module trying to ground through REF LO input to PCM). Note On Intermittents Code set due to an improperly mounted PCM, causing PCM not to be electrically isolated from body ground.

Fig. 85: Code P035 Schematic, Ignition Ground Voltage Out Of Range Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 117)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 86: Code P035 Diagnostic Flow Chart, Ignition Ground Voltage Out Of Range Courtesy of General Motors Corp.

CODE P036, EGR PINTLE POSITION OUT OF118) RANGE 1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 G - TESTS W/CODES - 4.6LArticle Text (p.

Code P036 sets when EGR pintle position cannot be controlled by PCM. Test Conditions Ignition voltage at 11 volts or greater.

Failure Conditions Difference between commanded and actual EGR position is greater than 25 counts for 10 seconds or learned EGR closed position is less than 9 counts or greater than 103 counts. Action PCM turns on MIL. PCM disables EGR solenoid for entire ignition cycle. Transaxle shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if EGR pintle position feedback is within a valid range with EGR off. 2) This step forces a high signal on the feedback circuit and checks for an appropriate result. 3) This step removes signal from feedback circuit and checks for an appropriate result. 4) Jumper voltage should read 5 volts since 5-volt reference line is jumpered to feedback line. 5) With EGR off (EGR overridden to zero), EGR pintle position should read less than 50 counts. 6) With EGR valve commanded to 50 percent, EGR pintle position should read 100-150 counts. 7) With EGR valve on full, EGR pintle position should be greater than 200 counts. 8) Code P036 snapshot parameter PD07 (EGR pintle position) can help determine the root cause even if problem cannot be reproduced. A low pintle position (less than 9 counts) recorded in the snapshot means a low feedback voltage caused the code to set. A high pintle position (greater than 250 counts) recorded in the snapshot means a high feedback voltage caused the code to set. An intermittent pintle position (9-250 counts) recorded in the snapshot means that code was set because PCM could not control the EGR solenoid either due to intermittents in the solenoid (circuits No. 435 and 741) or EGR valve is sticking.

G - TESTS W/CODES - 4.6LArticle Text (p. 119)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 87: Code P036 Schematic, EGR Pintle Position Out Of Range Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 120)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 121)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 88: Code P036 Diagnostic Flow Chart - 1 Of 2, EGR Pintle Position Out Of Range Courtesy of General Motors Corp.

Fig. 89: Code P036 Diagnostic Flow Chart - 2 Of 2, EGR Pintle Position Out Of Range Courtesy of General Motors Corp. CODE P037, SHORTED INTAKE AIR TEMPERATURE (IAT) SENSOR

IAT sensor is a thermistor that varies its resistance with temperature. As sensor temperature increases, resistance decreases. High temperature will result in low signal voltage. Code P037 sets when PCM sees an IAT sensor reading of 298øF (148øC) when coolant temperature is less than 212øF (100øC).

G - TESTS W/CODES - 4.6LArticle Text (p. 122)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Test Conditions Codes P014 and P015 not set. Coolant sensor temperature less than or equal to 212øF (100øC). Failure Conditions IAT sensor value greater than or equal to 298øF (148øC). Action

PCM turns on MIL. PCM substitutes outside air temperature for IAT. Transaxle shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) With a shorted IAT sensor, PCM parameter PD05 should indicate 148øC or greater. If PD05 does not indicate 148øC or greater, sensor is not shorted. 2) Checks for sensor short or circuit No. 472 shorted to ground. If PCM parameter PDO5 stays at 147-151øC with sensor unplugged, circuit is shorted to ground. 3) Checks shorted sensor or circuit No. 472 shorted to ground inside intake manifold. If PCM data PD05 stays at 147-151øC with sensor unplugged, circuit No. 472 is sorted to ground. 4) IAT sensors can be damaged by a backfire in intake. If vehicle has had more than one IAT sensor replaced, check for signs of backfire and high intake manifold temperatures due to improper valve train operation.

Fig. 90: Code P037 Schematic, Shorted IAT Sensor Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 123)1995 Cadillac ConcoursFor Ace Mechanics 123 Main

Fig. 91: Code P037 Diagnostic Flow Chart, Shorted IAT Sensor Courtesy of General Motors Corp. CODE P038, OPEN INTAKE AIR TEMPERATURE (IAT) SENSOR

IAT sensor is a thermistor that varies its resistance based on temperature. As temperature of sensor decreases, sensor resistance increases. Code P038 sets when PCM sees low voltage signal when coolant sensor temperature is 14øF (-10øC) or greater. Test Conditions Code P047 not set. Outside air temperature sensor has not failed. Outside air temperature 14øF (-10øC) or greater or difference between outside air temperature and IAT is greater than 63øF (17øC). Vehicle speed at 7 MPH or greater for at least 5 seconds. Engine speed at 500 RPM or greater for more than 20 seconds. Failure Conditions IAT sensor value less than 35øF (-37øC).

G - TESTS W/CODES - 4.6LArticle Text (p. 124)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Action PCM turns on MIL. PCM substitutes outside air temperature for IAT. Transaxle shift adapts are maintained at current levels.

NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If IAT sensor is open, PCM parameter PD05 should indicate -37øC or less. If PD05 does not indicate -37ø or less, sensor signal is not open. 2) Checks PCM and circuit No. 472 from PCM to sensor connector. If PCM data PD05 indicates 147-151øC with connector terminal "A" shorted to ground, sensor circuits and PCM are okay. 3) Checks for open sensor circuit No. 452 (ground). If PCM data PD05 reads 147-151øC with sensor connector terminals "A" and "B" jumpered, then circuit No. 452 and PCM are okay. 4) Checks if circuit No. 472 or if PCM is open. 5) Checks if circuits No. 452 or 472 or IAT sensor is open or shorted to voltage. 6) IAT sensor can be damaged by backfire in intake manifold. If vehicle has had multiple IAT sensor replacements, check for signs of backfire.

Fig. 92: Code P038 Schematic, Open Intake Air Temperature (IAT) Sensor Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 125)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 93: Code P038 Diagnostic Flow Chart, Open IAT Sensor Courtesy of General Motors Corp. CODE P039, TCC ENGAGEMENT PROBLEM

G - TESTS W/CODES - 4.6LArticle Text (p. 126)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 This code test monitors engine RPM and vehicle speed and compares them. PCM will set code when engine speed exceeds fault value for a particular vehicle speed. This code can set due to an electrical problem or slippage of TCC or transaxle clutches. If a TCC failure has

occurred, failure is more likely to be observed under high road load (high MAP) conditions. Use code snapshot data to confirm failure. Test Conditions Codes P024, P026, P027, P028, P031, P032, P034, P056 and P075 not set, transaxle in 3rd or 4th gear and engine running. TCC commanded on (100 percent). Transaxle not in Park or Neutral. Throttle position switch open. Delivered torque from engine not 32 ft. lbs. or less (coast down condition). Delivered torque from engine not 508 ft. lbs. or greater (engine under extreme load). Failure Conditions: 3.11 Ratio (VIN Y) - Slip speed greater than acceptable value based on engine torque delivered for 4.5 seconds. See chart. 3.71 Ratio (VIN 9) - Slip speed at 48 RPM or greater for 4.5 seconds. Action PCM turns on MIL. TCC disabled for the entire ignition cycle. NOTE:

Test number refers to number on diagnostic chart.

1) Testing TCC brake switch input to PCM PI71. If test passes, display will change from HI 0 to HI X. If test fails, display will not change. 2) Checks for open in circuit No. 420 between TCC solenoid and TCC brake switch connectors. 3) Checks for open or short inside transaxle. Resistance should be 10-40 ohms. 4) Checks if circuit No. 422 is open or if PCM in unable to control output. 5) Checks PCM's ability to control TCC output. 6) Checks if TCC is operating correctly by checking amount of TCC slip when clutch is engaged. Note On Intermittent Intermittent Code P039 nay be caused by delayed TCC engagement (usually first apply after a cold start) or by TCC slippage during high engine load conditions. Delayed TCC engaged can be checked using PCM output override PS01 (TCC solenoid) to engage and disengage and time how long it takes TCC to engage by watching PCM data PD73. Delays of greater than 5 seconds may cause code to set. TCC slippage during high load conditions can be determined by looking at Code P039 snapshot data. High throttle angle (PD01), MAP (PD02) may indicate a high load condition. Duplicating high load conditions may cause the code to set.

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Fig. 94: Code P039 Schematic - 1 Of 2, TCC Engagement Problem Courtesy of General Motors Corp.

Fig. 95: Code P039 Schematic - 2 Of 2, TCC Engagement Problem G - TESTS W/CODES - 4.6LArticle (p. 128)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Courtesy of General MotorsText Corp.

Fig. 96: Code P039 Diagnostic Flow Chart - 1 Of 2, TCC Engagement Problem Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 129)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 97: Code P039 Diagnostic Flow Chart - 2 Of 2, TCC Engagement G - TESTS W/CODES - 4.6LArticle Text (p. 130)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Problem Courtesy of General Motors Corp. CODE P040, OPEN PSPS CIRCUIT

This code test monitors Power Steering Pressure Switch (PSPS). When a load is placed on power steering, such as full lock, switch opens. Code P040 sets when vehicle speed is greater than 45 MPH

and pressure switch is open. Test Conditions Engine running. Vehicle speed greater than or equal to 45 MPH. Failure Conditions Power steering switch open for 60 seconds. Action PCM turns on MIL. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if PI85 will cycle from high to low to high. If PI85 stays low, check for open or short to ground in circuit. If PI85 stays high, check for short to voltage in circuit. 2) Checks is circuit No. 495 is shorted to voltage or if power steering is faulty. 3) Checks if circuit No. 741 or fuse D1 is open. 4) Checks if power steering pressure switch is open. 5) Checks if circuit No. 495 is open or if PCM is faulty.

Fig. 98: Code P040 Schematic, Open PSPS Circuit Courtesy of General Motors Corp.

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Fig. 99: Code P040 Diagnostic Flow Chart, Open PSPS Circuit Courtesy of General Motors Corp. CODE P041, NO CAM REFERENCE SENS SGNL FROM IGN CONTROL MODULE

1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 G - TESTS W/CODES - 4.6LArticle Text (p. 132)pulses Checks for CAM reference not received when 4X

reference pulses are being received. This indicates a cam sensor circuit failure and Code P041 will set. Test Conditions Code P012 not set, 4X reference pulses being received and RPM 1600 or less. Failure Conditions PCM receives no cam sensor pulses for 5.3 seconds. Action PCM turns on MIL. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if Code P035 is set because a REF LO problem can cause other ignition problems. 2) Checks resistance of camshaft position sensor. Resistance should be 800-1200 ohms. If resistance is greater, check for an open circuit. If resistance is less, check for a short. 3) Checks if circuits No. 632 or 633 is shorted to ground. 4) Checks if sensor is able to produce a DC voltage greater than 0.2 volt. If it can, sensor is okay. 5) A reading of 4 Hertz with engine running means that ignition control module is producing cam pulses. 6) Checks if circuit is at fault or if ICM is faulty.

Fig. 100: Code P041 Schematic, No CAM Reference Sensor Signal From Ignition Control Module Courtesy of General Motors Corp. G - TESTS W/CODES - 4.6L

Fig. 101: Code P041 Diagnostic Flow Chart, No CAM Reference Sensor Signal From Ignition Control Module Courtesy of General Motors Corp. CODE P042, FRONT OXYGEN SENSOR LEAN SIGNAL

G - TESTS W/CODES - 4.6LArticle Text (p. 134)1995 Cadillac Concours

PCM provides a .45-volt reference signal to oxygen sensor on circuit No. 412. When oxygen sensor temperature is less than 392øF (200øC), sensor signal voltage will be about .45 volt and PCM will keep system in open loop operation. When oxygen sensor temperature is greater than 392øF (200øC), sensor will begin to generate a signal voltage. In a rich environment, signal voltage will be greater than . 45 volt. In a lean environment, signal voltage will be less than .45 volt. If PCM is in good control of air/fuel mixture, mixture will change from rich to lean rapidly (at least one change every 2 seconds). When PCM sees oxygen sensor is generating a signal voltage (greater than .45 volt), PCM will send system into closed loop operation. In closed loop operation, PCM will adjust fuel delivery rate to engine based on oxygen sensor readings. Code P042 sets if oxygen sensor stays at lean voltage more than 50 seconds during test conditions. Code P042 also sets when an oxygen sensor circuit fault giving a false lean indication exists or when air/fuel ratio is actually lean due to a vacuum leak or fuel control system fault. Test Conditions Codes P014, P015, P016, P021, P022, P026, P027, P031, P032 and P034 not set. Throttle switch open, throttle angle 5-25 degrees, coolant temperature 180-268øF (82-131øC), oxygen sensor ready (closed loop), RPM at least 800 and MAP at least 32 kPa. Canister purge occurred at full duty cycle for 2 minutes since engine was running and throttle angle 10 degrees or greater. Long term fuel trim not in effect. Failure Conditions Oxygen sensor status stays lean more than 50 seconds. Action PCM turns on MIL. PCM turns on canister purge solenoid if Code P044 is also set. Transaxle shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If Code P017 is present, diagnose this code first since an oxygen sensor not ready can cause other emission related problems. 2) If oxygen sensor is operating correctly, voltage should fluctuate at greater than 0.3 volt. A lean sensor condition will cause voltage to remain at less than 0.3 volt. 3) If voltage measured is greater than 0.15 volt, PCM and circuit No. 412 are okay.

G - TESTS W/CODES - 4.6LArticle Text (p. 135)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 102: Code P042 Schematic, Front O2 Sensor Lean Signal Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 136)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 137)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Fig. 103: Code P042 Diagnostic Flow Chart, Front O2 Sensor Lean Signal Courtesy of General Motors Corp. CODE P043, FRONT OXYGEN SENSOR RICH SIGNAL

PCM provides a .45-volt reference signal to oxygen sensor on circuit No. 412. When oxygen sensor temperature is less than 392øF (200øC), sensor signal voltage will be about .45 volt and PCM will keep system in open loop operation. When oxygen sensor temperature is greater than 392øF (200øC), sensor will begin to generate a signal voltage. In a rich environment, signal voltage will be greater than . 45 volt. In a lean environment, signal voltage will be less than .45 volt. If PCM is in good control of air/fuel mixture, mixture will change from rich to lean rapidly (at least one change every 2 seconds). When PCM sees oxygen sensor is generating a signal voltage (greater than .45 volt), it will send system into closed loop operation. In closed loop operation, PCM will adjust fuel delivery rate to engine based on oxygen sensor readings. Code P043 sets if oxygen sensor stays at rich voltage more than 45

seconds during test conditions. Code P043 also sets when oxygen sensor circuit fails or when air/fuel ratio is actually rich due to fuel control or emissions system fault. Test Conditions Codes P014, P015, P016, P021, P022, P026, P027, P031, P032 and P034 not set, throttle switch open, throttle angle 5-30 degrees, coolant sensor temperature 180-268øF (82-131øC), sensor ready (closed loop), vehicle not accelerating or decelerating, and engine speed greater than or equal to 800 RPM. Canister purge occurred at full duty cycle for 2 minutes since engine was running and throttle angle at 10 degrees or greater. Long term fuel trim not in effect. Failure Conditions Oxygen sensor stays rich for more than 50 seconds. Action PCM turns on MIL. PCM turns on canister purge solenoid if Code P045 is also set. Transaxle shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If Code P017 is present, diagnose this code first since an oxygen sensor not ready can cause other emission related problems. 2) If oxygen sensor is operating correctly, voltage should fluctuate at less than 0.6 volt. A rich sensor condition will cause voltage to remain at greater than 0.6 volt. 3) If voltage measured is less than one volt, PCM and circuit No. 412 are okay.

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Fig. 104: Code P043 Schematic, Front O2 Sensor Rich Signal Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 139)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 140)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Fig. 105: Code P043 Diagnostic Flow Chart, Front O2 Sensor Rich Signal Courtesy of General Motors Corp. CODE P044, REAR OXYGEN SENSOR LEAN SIGNAL

PCM provides a .45-volt reference signal to oxygen sensor on circuit No. 1670. When oxygen sensor temperature is less than 392øF (200øC), sensor signal voltage will be about .45 volt and PCM will keep system in open loop operation. When oxygen sensor temperature is greater than 392øF (200øC), sensor will begin to generate a signal voltage. In a rich environment, signal voltage will be greater than . 45 volt. In a lean environment, signal voltage will be less than .45 volt. If PCM is in good control of air/fuel mixture, mixture will change from rich to lean rapidly (at least one change every 2 seconds). Code P044 sets if oxygen sensor stays at lean voltage for more than 50 seconds during test conditions. Code P044 also sets when oxygen sensor circuit fails or when air/fuel ratio is actually lean due to vacuum leak or fuel control system fault.

Test Conditions Codes P014, P015, P016, P021, P022, P026, P027, P031, P032 and P034 not set. Throttle switch open, throttle angle 5-25 degrees, coolant sensor temperature 180-268øF (82-131øC), sensor ready (closed loop), RPM greater than or equal to 800 and MAP at 32 kPa or greater. Canister purge occurred at full duty cycle for 2 minutes since engine was running and throttle angle 10 degrees or greater. Long term fuel trim not in effect. Failure Conditions Oxygen sensor status stays lean more than 50 seconds. Action PCM turns on MIL. PCM turns on canister purge solenoid if Code P042 is also set. Transaxle shift adapts maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If Code P013 is present, diagnose this code first since an oxygen sensor not ready can cause other emission related problems. 2) If oxygen sensor is operating correctly, voltage should fluctuate at greater than 0.3 volt. A lean sensor condition will cause voltage to remain at less than 0.3 volt. 3) If voltage measured is greater than 0.15 volt, PCM and circuit No. 1670 are okay.

Fig. 106: Code P044 Schematic, Rear O2 Sensor Lean Signal Courtesy of General Motors Corp. G - TESTS W/CODES - 4.6LArticle Text (p. 141

Fig. 107: Code P044 Diagnostic Flow Chart, Rear O2 Sensor Lean Signal Courtesy of General Motors Corp. CODE P045, REAR OXYGEN SENSOR RICH SIGNAL

PCM provides a .45-volt reference signal to oxygen sensor on circuit No. 1670. When oxygen sensor temperature is less than 392øF (200øC), sensor signal voltage will be about .45 volt and PCM will keep system in open loop operation. When oxygen sensor temperature is greater than 392øF (200øC), sensor will swing from rich to lean rapidly, at least one swing every 2 seconds, if PCM is in good control of air/fuel mixture. Code P045 sets when sensor stays at a rich voltage for more than 50 seconds during the test conditions. Code P045 will also set when oxygen sensor circuit fails or when air/fuel ratio is actually rich due to fuel control or emissions system fault.

Test Conditions Codes P014, P015, P016, P021, P022, P026, P027, P031, P032 and P034 not set. Throttle switch open, throttle angle 5-25 degrees, coolant temperature 180-268øF (82-131øC), oxygen sensor ready (closed loop), and engine speed at least 800 RPM. Canister purge occurred at Cadillacwas ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 G - TESTS W/CODES - 4.6LArticle Text (p. 142)1995 full duty cycle for 2 minutes since engine running and throttle

angle at 10 degrees or greater. Long term fuel trim not in effect. Failure Conditions Oxygen sensor stays rich for more than 50 seconds. Action PCM turns on MIL. PCM turns on canister purge solenoid if Code P043 is also set. Transaxle shift adapts maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If Code P013 is present, diagnose this code first since an oxygen sensor not ready can cause other emission related problems. 2) If oxygen sensor is operating correctly, voltage should fluctuate at less than 0.6 volt. A rich sensor condition will cause voltage to remain at greater than 0.6 volt. 3) If voltage measured is less than one volt, PCM and circuit No. 1670 are okay.

Fig. 108: Code P045 Schematic, Rear O2 Sensor Rich Signal Courtesy of General Motors Corp.

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Fig. 109: Code P045 Diagnostic Flow Chart, Rear O2 Sensor Rich Signal Courtesy of General Motors Corp. CODE P046, FRONT-TO-REAR BANK FUELING IMBALANCE

PCM controls rear bank fueling based upon rear oxygen sensor and front bank fueling based upon front oxygen sensor. Likely causes for imbalance include lean or faulty injectors on one side of engine, cracked or fouled spark plugs, or exhaust or intake manifold leaks. Test Conditions Tested continuously. Failure Conditions Front bank block learn values differ from rear bank block learn values by more than 15 counts for 10 minutes.

Action PCM turns on MIL. G - TESTS W/CODES - 4.6LArticle Text (p. 144)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 NOTE: Test numbers refer to numbers on diagnostic chart.

1) If any other codes are present, diagnose them first because they can cause a fueling imbalance. 2) This test checks for a physical or mechanical problem causing Code P046 to set. 3) Injector bank that is farthest from neutral value of 128 is bank which is out of fuel. Refer to PCM DATA PARAMETER. See Fig. 2. See appropriate chart under POWERTRAIN CHARTS.

Fig. 110: Code P046 Schematic, Front-To-Rear Bank Fueling Imbalance Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 145)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 111: Code P046 Diagnostic Flow Chart, Front-To-Rear Bank Fueling Imbalance Courtesy of General Motors Corp. CODE P047 & P107, IPC-TO-PCM DATA LINK PROBLEM

PCM and IPC share information through Universal Asynchronous Receiver Transmitter (UART). is1995 master and Ace data are only Cadillaclink ConcoursFor Mechanics 123 Main Street San Diego Ca 92 G - TESTS W/CODES - 4.6LArticle Text IPC (p. 146) transmitted at IPC request. Data are sent in 8-character blocks at a rate of 8192 characters per second. Data from PCM to IPC contain engine operating information. PCM-IPC data include CTS, RPM and injector pulse width values so IPC can control cooling fans, display RPM and calculate MPG for display at Driver Information Center (DIC) panel. IPC sends PCM A/C status to be used for idle speed control and ambient temperature for use in TCC application and release decisions. Codes P047/P107 are set in PCM in event of a UART failure. If fault is a current failure, PCM will not be able to communicate with IPC and IPC Code IO34 will be displayed as current. Code P047/P107 is current in PCM but cannot be sent (displayed) to IPC because of UART fault. If UART fault is corrected, Codes P047, P107 and IPC Code IO34 will be displayed as history codes. Code P047 & P107 should be diagnosed using chart for IPC Code

IO34. Code P047 stored as history can indicate 2 failures: *

Open in circuit No. 800. Symptoms will be: A B C D

*

-

SYSTEM FAULT message on DIC panel. MIL and CHECK INFO CENTER lights on. Diagnostics entered; NO PCM DATA displayed on DIC panel. When fault is repaired, Codes P047 and IO34 will show as history codes.

Grounded circuit No. 800 at any point. Symptoms will be: A B C D E E

-

SYSTEM FAULT message on DIC panel. SERVICE VEHICLE SOON light on. Instrument panel gauges flash. Climate control panel goes blank. Engine cooling fans go on high speed. Diagnostics disabled; SYSTEM FAULT message stays on DIC panel. F - When fault is repaired, diagnostics show Codes P047, I033, I034 and I037 as history codes. Test Conditions Code P012 not set and engine speed greater than 500 RPM for 20 seconds. Failure Conditions PCM receives invalid data from IPC for 5 seconds. Action PCM turns on MIL. PCM sets all data to zero. PCM boosts idle to compensate for possible A/C clutch engagement. Cooling fan control will be based on engine coolant temperature only. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If one code is set without the other, PCM has an internal communication problem. 2) Checks if data link is not functioning at all. 3) Checks if PROM is seated correctly in socket. 4) Checks which components have data link problem to IPC. 5) Checks if IPC is having data link problem with PCM or if PCM is having a data link problem with IPC. 6) Checks if data link is open or if PCM is faulty. 7) Checks for wake-up sequence problem.

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Fig. 112: Code P047 & P107 Schematic, IPC-To-PCM Data Link Problem Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 148)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 149)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 113: Code P047 & P107 Diagnostic Flow Chart, IPC-To-PCM Data Link Problem Courtesy of General Motors Corp. CODE P048, EGR SYSTEM FAULT

To perform test, PCM turns off EGR flow to engine and

monitors oxygen sensor (closed loop) integrator. With EGR off, integrator should swing to a greater value, reflecting leaner air/fuel mixtures. If integrator does not swing to a greater value, PCM assumes either EGR was turned off before test started or EGR is flowing and PCM does not have ability to turn it off. PCM monitors EGR 5 times in a given key cycle. If EGR does not respond 3 or more times during a key cycle, Code P048 is set. Test Conditions EGR failed in entire ignition cycle. Codes P013, P014, P015, P017, P021, P022, P024, P031, P032, P034, P042, P043, P044, P045 and P075 not set and 9.2 seconds have elapsed since closed loop fuel control was enabled. Coolant temperature 176-230øF (80-110øC), MAP between 50-80 kPa. Engine speed between 1250-1850 RPM and vehicle speed at 35 MPH or greater. Ignition voltage at 11 volts or greater, and 5 seconds prior to test EGR system at full, rear oxygen sensor toggles for 5 times per second and rear short term fuel trim is at 135 counts or less. Failure Conditions PCM turns off EGR system for 5 seconds. PCM monitors rear fuel integrator for change. Oxygen sensor fails to indicate a leaner mixture in at least 3 of 5 tests during key cycle. Action PCM turns on MIL. EGR is disabled for entire key cycle and transaxle shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Diagnose Code P036 first because it can cause EGR system malfunction. 2) If rear bank long term trim is 15 counts or greater than front bank long term trim, a fuel control problem exists. Use Code P046 to diagnose. 3) Checks for a rich engine condition causing Code P048 to set. 4) Checks if by using PCM overrides if EGR valve can be shut off (less than 100 counts). 5) Checks if by using PCM overrides if EGR can be returned to full on (greater than 200 counts). 6) Checks circuit No. 741 and fuse D1 for open. 7) Checks if EGR circuit is open. 8) Checks if circuit No. 435 is open. 9) Checks if PCM is open internally or if circuit No. 435 is shorted to voltage. 10) Checks if EGR valve can correctly respond to PCM signal. G - TESTS W/CODES - 4.6L

Fig. 114: Code P048 Schematic, EGR System Fault Courtesy of General Motors Corp.

Fig. 115: Code P048 Diagnostic Flow Chart - 1 Of 2, EGR System Fault Courtesy of General Motors Corp. G - TESTS W/CODES - 4.6LArticle Text (p. 151)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 116: Code P048 Diagnostic Flow Chart - 2 Of 2, EGR System Fault Courtesy of General Motors Corp. CODE P051 & P108, PROM CHECKSUM MISMATCH

PCM PROM contains data essential in running engine and transaxle. Codes P051 and P108 checks the integrity of this data. RPM is divided into 2 halves or sides in the PROM. Code P051 checks one half of this data and Code P108 checks the other half. Integrity of this data is checked by adding up the data in all locations of the PROM, called the checksum. If checksum does not equal to what it should, code is set. The checksum is only checked when ignition is turned off and if it does not match, trouble code will set next time ignition is turned on. Ace Mechanics 123 Main PCM Street San Diego Ca 92 G - TESTS W/CODES 4.6LArticle (p. 152) Trouble - codes canText also be 1995 due Cadillac to a ConcoursFor bad connection between

and PROM, incorrect data in PCM due to electromagnetic discharge. Faulty PROM or internal PCM problem. NOTE:

To prevent electrostatic discharge damage, DO NOT touch PCM and PROM connector pins or soldered components on circuit board.

Ensure PROM is fully inserted in socket. If PROM is fully inserted, replace PROM. Clear memory and recheck. If Code P051 or P108 reappears, replace PCM.

Fig. 117: Code P051 & P108, Prom Checksum Mismatch Courtesy of General Motors Corp. CODE P052 & P109, PCM KEEP ALIVE MEMORY RESET

This code test monitors PCM's keep alive memory for a loss or unintended change of data setting Codes P052 and P109. These codes indicate that long term memory in PCM has been reset. Test Conditions Tested continuously.

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Failure Conditions Keep alive memory checksum does not match previous checksum. Action None. Notes On Intermittents If battery has been disconnected for any reason, Codes P052 and P109 will set. PCM keeps a running check on the memory, if memory changes it resets. Codes P052 and P109 may also set while keying OFF in diagnostics. If IPC is sending new information to PCM when ignition switch is turned off, making PCM think it has been switched off, causing a reset.

Fig. 118: Code P052 & P109 Schematic, PCM Keep Alive Memory Reset Courtesy of General Motors Corp. CODE P053, 4X REFERENCE SGNL INTERRUPT FROM IGN CNTRL MODULE

Code P053 is set if PCM does not receive 4X reference pulses Cadillac Concours from Ignition Control Module (ICM) for more than .4 second. G - TESTS W/CODES - 4.6LArticle Text (p.Since 154)1995PFI

system requires ICM pulses in order to trigger injectors, most occurrences of Code P053 will be accompanied by a stall. Test Conditions Code P019 and P035 not set and engine speed greater than 568 RPM. Failure Conditions No 4X reference pulses received by PCM for .4 second. Action Code P053 is set. MIL is not illuminated. NOTE:

Test number refers to number on diagnostic chart.

1) Checks to see if Code P035 is set. A REF LO problem can cause other ignition problem. 2) Checks for power to ignition control module. 3) Checks ignition control module's ability to produce 4X reference pulses. If system is operating correctly, reading will be 30 Hertz or greater. 4) Open at fuse block. Check terminal contact. 5) Checks for open or short on circuit No. 430. Note On Intermittents This code sets due to a false start condition which engine speed exceeds 568 RPM but does not start.

Fig. 119: Code P053 Schematic, 4X Reference Signal Interrupt From Ignition Control Module Courtesy of General Motors Corp.

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Fig. 120: Code P053 Diagnostic Flow Chart, 4X Reference Signal Interrupt From Ignition Control Module Courtesy of General Motors Corp. CODE P055, CLOSED TP SENSOR OUT OF RANGE

G - TESTS W/CODES - 4.6LArticle Text (p. 156)1995 Cadillac Concours

TP sensor is self-adjusting. With ignition off, PCM executes a TP sensor learning routine. After ignition is turned off, PCM will retract ISC until ISC throttle switch opens and throttle linkage is resting on minimum air screw. PCM then stores TP sensor value and calculates a correction. If same correction factor occurs on 2 consecutive key off cycles, TP sensor is corrected to zero degrees using correction factor learned. If value needs correction by greater than 6.5 degrees, Code P055 will be stored in memory at next key on cycle. Parameter PD01 displays incorrect TP sensor values. Test Conditions Tested continuously. Failure Conditions "Learned" TP sensor is less than 6.5 degrees or greater. Action PCM learned TP sensor value set to zero. NOTE:

Test numbers refer to numbers on diagnostic chart. 1) Checks for ISC/TP sensor codes causing Code P055 to set. 2) Checks if TP sensor is really out of range or if TP switch

is open. 3) Checks TP sensor adjustment. PCM Data PD01, TP sensor displays incorrect TP sensor so that it can be used to check TP sensor adjustment. 4) If TP sensor is within range, ISC and throttle switch operation need to be checked. Check throttle linkage for proper operation, cruise control cable, proper throttle return spring operation and that throttle shaft and blades are free.

G - TESTS W/CODES - 4.6LArticle Text (p. 157)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 121: Code P055 Schematic, Closed TP Sensor Out Of Range Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 158)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 159)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 122: Code P055 Diagnostic Flow Chart, Closed TP Sensor Out Of Range Courtesy of General Motors Corp. CODE P056, TRANSAXLE INPUT SPEED SENSOR CIRCUIT PROBLEM

This test checks transaxle input speed sensor circuit problem. If engine is running and vehicle is moving at greater than 10

MPH, then transaxle input speed must be non-zero. If turbine speed is less than 50 MPH with vehicle speed of 10 MPH or greater, Code P056 will set. Test Conditions Codes P024, P075 and P091 not set. Transaxle not in Park or Neutral. Engine running and vehicle speed at 10 MPH or greater. Failure Conditions PCM turns on MIL. PCM calculates transaxle input speed based on output speed and gear ratio of gear commanded. PCM calculates slip speed from calculated input speed and engine RPM. TCC engaged and garage shift adapts are maintained at current levels. Torque management is disabled. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) With engine idling in Park or Neutral, PCM data PD72 should read 50-100 RPM less than engine RPM. 2) Transaxle input speed sensor should generate a frequency of greater than zero Hertz with engine at idle. If frequency is not as specified, check circuits No. 1230 and 1231 and speed sensor for open or short inside transaxle. 3) Checks circuits No. 1230 and 1231 for open or short to PCM. If circuit is okay, PCM is faulty. Note On Intermittents Manipulate circuits No. 1230 and 1231. Look for EMI sources, such as sensor wires running along spark plug cables or high power transmitters in vicinity.

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Fig. 123: Code P056 Schematic, Transaxle Input Speed Sensor Circuit Problem Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 161)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 162)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 124: Code P056 Diagnostic Flow Chart, Transaxle Input Speed Sensor Circuit Problem Courtesy of General Motors Corp. CODE P057, SHORTED TRANSAXLE TEMPERATURE SENSOR CIRCUIT

Transaxle temperature sensor resistance decreases as sensor temperature increases. A high transaxle temperature will result in low signal voltage on circuit No. 585 (Tan/White wire). Code P057 sets when PCM sees a transaxle temperature reading of 298øF (148øC) or greater (.08 volt or less). Test Conditions Test continuously. Failure Conditions Transaxle temperature sensor value at 298øF (148øC) or greater for 5 seconds. Action

PCM turns on SERVICE VEHICLE SOON message. PCM substitutes engine coolant temperature value for transaxle temperature until engine coolant temperature reaches 221øF (105øC) before it sets to hot mode operation. Transaxle shift adapts and garage shift adapts are maintained in current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If transaxle temperature sensor is shorted, PCM data parameter PD77 should read 298øF (148øC) or greater. If parameter does not show this reading, sensor and wiring are okay. 2) Checks if circuit No. 585 (Tan/White wire) is shorted. If parameter value stays at -18øF (-28øC) or greater with transaxle temperature sensor connector disconnected, check for short between sensor connector and PCM terminal No. 1B14. 3) Checks for short to ground on circuit No. 585 (Tan/White wire) inside transaxle. If wire is okay, replace shorted transaxle temperature sensor.

Fig. 125: Code P057 Schematic, Shorted Transaxle Temp. Sensor Circuit Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 163)1995 Cadillac ConcoursFor Ace Mechanics 123 Main

Fig. 126: Code P057 Diagnostic Flow Chart, Shorted Transaxle Temp. Sensor Ckt. Courtesy of General Motors Corp. CODE P058, PASS-KEY(R) FUEL ENABLE PROBLEM

PASS-Key(R) system enables engine operation by allowing starter to engage and issuing a fuel enable signal to PCM. Once engine is running, PCM constantly monitors fuel enable signal from PASSKey(R) module. PCM will not cancel fuel injection once it has seen a proper PASS-Key(R) module signal; therefore, stalling conditions cannot occur as a result of a PASS-Key(R) malfunction. Test Conditions Engine has been running for a predetermined amount of time. PASS-Key(R) engine start timer expired.

Failure Conditions PASS-Key(R) fuel enable input incorrect but has been correct G - TESTSthis W/CODES - 4.6LArticle Text (p. 164)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 within engine run cycle. Action "THEFT SYSTEM PROBLEM, CAR MAY NOT RESTART" message is displayed on DIC. Enables fuel injection on future ignition cycles

without regard for PASS-Key(R) fuel enable input status. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If engine will crank, problem has been isolated to PASSKey(R) module, PCM or fuel enable circuit. If engine will not crank, perform PASS-Key(R) system diagnosis. See PASS-KEY(R) DIAGNOSIS. 2) Checking voltage to PCM will identify if PCM is at fault. Typical signal will be about 2-3 volts. 3) Checks if PCM is recognizing cranking fuel enable signal from PASS-Key(R) decoder module. 4) Checks circuit No. 229 for short or open circuit. If circuit is okay, check PASS-Key(R) module terminal contacts. Note On Intermittents If code is intermittent, check for short to ground or voltage on circuit No. 229, intermittent open in circuit No. 229 or intermittent loss of power to module. PASS-Key(R) Diagnosis PASS-Key(R) system interfaces PCM and starter with a power source, decoder module, starter enable relay, ignition switch and instrument cluster. Before replacing PASS-Key(R) module, check system for following common problems. *

* * *

Check ignition key pellet sensing contacts in ignition lock cylinder. Look into cylinder lock. If contacts are damaged, replace cylinder lock. Check PASS-Key(R), PCM and GAGES fuses. Check SECURITY indicator bulb in instrument panel. A defective resistor pellet within ignition key or incorrect resistance value of key (15 different assigned values) will cause vehicle not to start. Key must be correct electrically and mechanically.

If incorrect key is used to try to start vehicle, decoder will not allow vehicle to start for 2-4 minutes, even if after correct key is inserted.

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Fig. 127: Code P058 Schematic, Pass-Key(R) Fuel Enable Problem Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 166)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 167)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 128: Code P058 Diag. Flow Chart, Pass-Key(R) Fuel Enable Problem Courtesy of General Motors Corp. CODE P059, OPEN TRANSAXLE TEMPERATURE SENSOR CIRCUIT

Transaxle temperature sensor resistance varies based on its resistance. As sensor temperature increases, resistance decreases. A low transaxle temperature will result in high voltage in circuit No. 585. Code P059 sets when PCM sees a transaxle temperature sensor reading of -31øF(-35øC) or less (4.9 volts or greater). Test Conditions Codes P014, P015 and P024 not set. Coolant temperature at

-13.0øF (-25øC) or greater and vehicle speed greater than zero MPH. Failure Conditions Transaxle temperature sensor at -32øF (-36øC) or less for 6 seconds. Action PCM turns on MIL. PCM substitutes coolant temperature value for transaxle temperature until coolant temperature reaches 221øF (105øC) then transaxle will be set to hot mode operation. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) With transaxle temperature sensor or wiring open, PCM data PD77 will read -35øC or less. If parameter does not show this, sensor and circuit is okay. 2) Check for open in circuit No. 585 between PCM and sensor connector. If PCM data PD77 reads 148-151øC with sensor terminal "M" jumpered to ground, the circuit No. 585 and PCM are okay. 3) Checks circuit No. 452 for open to PCM terminal connector. 4) Checks PCM's ability to recognize low voltage on PCM terminal 1B14 (transaxle temperature sensor input). If grounding PCM terminal 1B14 caused PCM data PD77 to read 148-151øC, check for open in circuit No. 585 between PCM and sensor connector. 5) Checks for open transaxle temperature sensor.

Fig. 129: Code P059 Schematic, Open Transaxle Temperature Sensor Circuit G - TESTS W/CODES Courtesy of General Motors Corp.

Fig. 130: Code P059 Diagnostic Flow Chart, Open Transaxle Temperature Sensor Circuit Courtesy of General Motors Corp. CODE P060, CRUISE CONTROL WITH TRANSAXLE NOT IN DRIVE

Code P060 sets if cruise control is engaged and park/neutral switch is closed, indicating transaxle is in Park or Neutral. Test Conditions Cruise control on and engaged. Failure Conditions Transaxle in Park or Neutral. Action PCM disengages cruise control. NOTE:

Test numbers refer to numbers on diagnostic chart. G - TESTS W/CODES - 4.6LArticle Text (p. 169)1995 Cadillac Concours

1) Checks if Code P028 or P091 are set because they can cause Code P060 to set. 2) Checks if P/N input to PCM from transaxle range switch agrees with transaxle pressure switch. If they do, code was driver induced by shifting into Park or Neutral while cruise control was engaged. If not, check for intermittent fault.

Fig. 131: Code P060 Schematic, Cruise Control With Transaxle Not In Drive Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 170)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 132: Code P060 Diagnostic Flow Chart, Cruise Control With Transaxle Not In Drive Courtesy of General Motors Corp. CODE P061, CRUISE CONTROL VENT SOLENOID PROBLEM

Code P061 will set if PCM output PO07 is commanding vent solenoid off and feedback is indicating that it is on or PCM is commanding vent solenoid on and feedback is indicating that it is off for 0.5 second. G - TESTS W/CODES - 4.6LArticle Text (p. 171)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Test Conditions Tested continuously. Failure Conditions Cruise vent solenoid commanded off but feedback indicates solenoid is on or cruise vent solenoid commanded on but feedback indicates solenoid is off. Action PCM disables cruise control. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks to see if fault is due to cruise control servo or circuit. Frequency should cycle between zero and a non-zero number. If DVOM stays at zero, circuit or PCM is at fault. 2) Checks for short to voltage in circuit No. 403. 3) Checks for open in circuit No. 451. 4) Checks PCM's ability to control cruise control servo. Voltage should cycle between zero and 12 volts. If voltage does not cycle, check for open in circuit No. 403.

Fig. 133: Code P061 Schematic, Cruise Control Vent Solenoid Problem Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 172)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 173)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Fig. 134: Code P061 Diagnostic Flow Chart, Cruise Control Vent Solenoid Problem Courtesy of General Motors Corp. CODE P062, CRUISE CONTROL VACUUM SOLENOID PROBLEM

Code P062 will set if PCM output PO08 is commanding vacuum solenoid off and feedback is indicating that it is on, or PCM is commanding vacuum solenoid on and feedback is indicating that it is off for 0.5 second. Test Conditions Tested continuously.

Failure Conditions Cruise vacuum solenoid commanded off but feedback indicates solenoid is on, or cruise vacuum solenoid commanded on but feedback indicates solenoid is off. Action PCM disables cruise control. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if fault is due to cruise control servo or circuit. Frequency should cycle between zero and a non-zero number. If DVOM stays at zero, circuit or PCM is at fault. 2) Checks for short to voltage in circuit No. 205. 3) Checks for open in circuit No. 451. 4) Checks PCM's ability to control cruise control servo. Voltage should cycle between zero and 12 volts. If voltage does not cycle, check circuit No. 205 for open.

Fig. 135: Code P062 Schematic, Cruise Control Vacuum Solenoid Problem Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 174)1995 Cadillac Concours

Fig. 136: Code P062 Diagnostic Flow Chart, Cruise Control Vacuum Solenoid Problem Courtesy of General Motors Corp. CODE P063, VEHICLE SPEED & SET SPEED DIFFERENCE TOO HIGH

Code P063 will set and disengage cruise control if vehicle speed is 20 MPH greater than cruise set speed. Code P063 is designed to detect a cruise control problem that results in cruise overspeed or inability to hold speed. G - TESTS W/CODES - 4.6LArticle Text (p. 175)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Test Conditions

Tested when cruise control is enabled and engaged, and cruise control servo position is at 39 percent or greater. Failure Conditions Vehicle speed 20 MPH greater than set speed for .5 second. Action PCM disengages cruise control. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If Code P075 is set, diagnose code first because it can cause other speed related problems. 2) Checks if cruise control feedback is a value is zero to 6 or greater. 3) Checks if PCM and related circuit to cruise control servo is okay (4.6-5.1 volts). 4) Checks if circuit No. 398 for a short to voltage. 5) Checks if cruise control servo is able to respond correctly to signal from PCM. Notes On Intermittents If Code P063 is intermittent, ensure vehicle operator is not overrunning set speed by greater than 20 MPH. Trouble code will not set by vacuum leaks or vacuum supply problem. Trouble code can only be set by vehicle exceeding set speed by 20 MPH.

Fig. 137: Code P063 Schematic, Vehicle Speed & Set Speed Difference Too High G - TESTS Courtesy of General Motors Corp. W/CODES - 4.6LArticle Text (p. 176)1995 Cadillac ConcoursFor Ace Mech

Fig. 138: Code P063 Diagnostic Flow Chart, Vehicle Speed & Set Speed Difference Too High Courtesy of General Motors Corp. CODE P064, CRUISE CONTROL ENGAGED/ACCELERATION TOO HIGH

Code P064 will set whenGvehicle speed is increasing a 1995 Cadillac Concours - TESTS W/CODES - 4.6LArticle Text at (p. 177)

rapid rate (wheel spin). This protective measure prevents wheel spin on icy roads when cruise control is in operation. Test Conditions Tested continuously. Failure Conditions Vehicle speed increases greater than 16 MPH in one second with cruise control engaged. Cruise control disengages when code sets. Code sets when wheel spins due to slippery conditions. Action PCM disengages cruise control. If Code PO64 is present and no other cruise control faults exists, clear code and road test vehicle. If Code P075 is also present, check for sources of Electromagnetic Interference (EMI) such as VSS wire running along spark plug cables or high power transmitters, like mobile radios, operating in vicinity.

Fig. 139: Code P064 Schematic, Cruise Control Engaged/Acceleration Too High Courtesy of General Motors Corp. CODE P065, CRUISE CONTROL SERVO POSITION SENSOR FAILURE

G - TESTS W/CODES Cruise servo position sensor is a potentiometer that changes

resistance with servo position. Code P065 sets when PCM detects a low voltage, indicating a short to ground in cruise servo position sensor circuit. Test Conditions Tested continuously. Failure Conditions Cruise control servo position 1.9 percent or less for 0.9 second. Action PCM disables cruise control. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if cruise control feedback is a value that it should never be, even with servo fully released (0-2). 2) Checks PCM and circuit to cruise control servo are okay. Voltage reading should be 4.6-5.1 volts. 3) Checks circuit No. 399 for an open. 4) Checks circuit No. 398 for an open. 5) Checks circuit No. 398 for short to ground. If wire is okay, PCM is open internally. 6) Checks if cruise control servo is operating normally. If feedback is greater than 30, servo is operating correctly.

Fig. 140: Code P065 Schematic, Cruise Control Servo Position Sensor Failure Courtesy of General Motors Corp. G - TESTS W/CO

Fig. 141: Code P065 Diagnostic Flow Chart, Cruise Control Servo Position Sensor Failure Courtesy of General Motors Corp. CODE P066, ENGINE RPM TOO HIGH WITH CRUISE ENGAGED

G - TESTS W/CODES - 4.6LArticle Text (p. 180)1995 Cadillac Concours

Code P066 will set when engine speed is greater than 5975 RPM with cruise engaged. This may occur on slippery pavement, extended wide open throttle acceleration or for some other mechanical problems (such as transaxle slippage). Under these conditions, Code P066 is normal. Vehicle operator should be advised why cruise control deenergized. Clear code, and road test vehicle to verify normal operation. Test Conditions Cruise is enabled and engaged. Vehicle operator not manually controlling throttle position. Failure Conditions Engine at 5975 RPM or greater for 0.5 second with cruise control on and engaged. This may occur on slippery road conditions, extended wide open throttle acceleration or for some mechanical problems, such as transaxle slippage. Under these conditions Code P066 will set. This should be considered normal for cruise control to disengage. Clear code and road test vehicle to verify normal operation. Action PCM disengages cruise control.

Fig. 142: Code P066 Schematic, Engine RPM Too High With Cruise Engaged G - TESTS W/CODES - 4.6LArticle Text (p. 181)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Courtesy of General Motors Corp.

CODE P067, SET/COAST OR RESUME/ACCEL SWITCH SHORTED

When cruise control is on, system voltage is available at one side of normally open contact of SET/COAST and RESUME/ACCEL switches. If cruise control switch is in ON position, voltage is available to switches when ignition is turned on. If SET/COAST or RESUME/ACCEL switches were stuck on or shorted to power, cruise control operation would begin. To prevent this, Code P067 will set and cruise control operation is disabled if signal voltage from SET/COAST (circuit No. 84) or RESUME/ACCEL (circuit No. 87) is high continuously for 10 minutes. Cruise control will be disengaged until PCM sees a low voltage on both of these signals. Test Conditions Tested continuously. Failure Conditions SET/COAST and RESUME/ACCEL switches are both closed for 10 minutes. Action PCM disengages cruise control. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if PCM input data PI83 (SET/COAST) and PI84 (RESUME/ACCEL) will cycle from LO to HI to LO. If inputs remain high, a short to voltage in system is present. 2) Checks if SET/COAST and/or RESUME/ACCEL switches are shorted to voltage. 3) Checks if circuit No. 84 is shorted to voltage. 4) Checks if circuit No. 87 is shorted to voltage.

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Fig. 143: Code P067 Schematic, Set/Coast Or Resume/Accelerator Switch Shorted Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 183)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 144: Code P067 Diagnostic Flow Chart, Set/Coast Or Resume/Accelerator Switch Shorted G - TESTS W/CODES - 4.6LArticle (p. 184)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Courtesy of General MotorsText Corp. CODE P068, CRUISE CONTROL SERVO POSITION OUT OF RANGE

Code P068 is set and cruise control is disabled when cruise control servo feedback reading is significantly higher or lower than commanded value for a period of time. Test Conditions Cruise control engaged. Failure Conditions Throttle angle greater than 20 degrees and servo position sensor indicating a stroke of at least 7 percent greater than commanded value for 2 seconds.

Action PCM disables cruise control for entire ignition cycle. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks control servo. 2) Checks control servo. 3) Checks voltage on circuit relaxing.

if PCM override PS07 can fully retract cruise if PCM override PS07 is able to fully relax cruise to see if problem is due to binding or a short to No. 403 is keeping cruise control servo from fully

Fig. 145: Code P068 Schematic, Cruise Control Servo Position Out Of Range Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 185)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 146: Code P068 Diagnostic Flow Chart, Cruise Control Servo Position Out Of Range Courtesy of General Motors Corp. CODE P069, TRACTION CONTROL ACTIVE WHILE IN CRUISE

Code P069 will set when PCM detects that cruise control and traction control are active at the same time. This condition is caused by wheel spin due to slippery conditions while cruise control is active. When code sets, cruise control is disengaged. If no other cruise control or traction control codes are present, clear codes and verify correct cruise and traction control operation. G - TESTS W/CODES - 4.6LArticle Text (p. 186)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Test Conditions Cruise control engaged. Failure Conditions IPC serial data indicates traction control is active for 0.5 second.

Action PCM disables cruise control.

Fig. 147: Code P069 Schematic, Traction Control Active While In Cruise Courtesy of General Motors Corp. CODE P070, INTERMITTENT THROTTLE POSITION (TP) SENSOR SIGNAL

This test monitors MAP and TP sensors. Code P070 will set if MAP value remains constant and TP sensor value changes considerably. Engine operation requires that any large change in TP sensor value must be followed by a change in MAP sensor value. Test Conditions Codes P031, P032 and P034 not set. Throttle angle changes more than 5 degrees in 12.5 milliseconds (.0125 seconds). Engine not decelerating (MAP drops to 22 kPa or less). Engine not accelerating (MAP is within 7.4 kPa of atmospheric pressure). Engine running. Coolant level normal and engine not overheating. Traction control not active.

Failure Conditions MAP changes 3 kPa or less in .21 second following a 5 degree G W/CODES - 4.6LArticle Text (p. 187)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 or- TESTS greater change in throttle angle.

Action None. NOTE:

Test number refers to number on diagnostic chart. Reference to CHART 3 refers to POWERTRAIN CHARTS.

1) Checking Code P070 snapshot value is used to determine if an intermittent low or high voltage caused code to set. An intermittent low voltage can be caused by an open or short to ground in circuit No. 417, an open in circuit No. 474 or a faulty TP sensor. An intermittent high voltage can be caused by an open in circuit No. 808 or a short to voltage on circuit No. 417.

Fig. 148: Code P070 Schematic, Intermittent Throttle Position (TP) Sensor Signal Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 188)1995 Cadillac Con

Fig. 149: Code P070 Diagnostic Flow Chart, Intermittent TP Sensor Signal Courtesy of General Motors Corp. CODE P071, INTERMITTENT MAP SENSOR SIGNAL

This test monitors TP sensor, RPM, MAP, EGR flow and A/C clutch status. If MAP changes rapidly and all other parameters remain constant, Code P071 will set. Engine operation requires a large change in manifold pressure must be preceded by a change in throttle angle.

Test Conditions Codes P021 and P022 not set. TP sensor does not change more 1995 Cadillac ConcoursFor Main Street San Diego Ca 92 G - TESTS - 4.6LArticle Text (p. 189)Engine than 1.0 W/CODES degree for 1.01 seconds. speed does Ace notMechanics change123more than 500 RPM for 1.01 seconds. EGR does not change more than 4 percent for 1.01 seconds. A/C clutch not commanded on or off. Traction control not active and PCM receiving reference pulses from ICM at least every .3 seconds. Failure Conditions MAP sensor reading changes more than 6.3 kPa in 12.5

milliseconds (.0125 second). Action PCM uses substitute MAP value based on engine RPM and throttle position switch status. NOTE:

Test numbers refer to numbers on diagnostic chart. Reference to CHART 3 refers to POWERTRAIN CHARTS. 1) Checks if MAP can read BARO pressure correctly (87-105

kPa). 2) Checks MAP sensor's ability to react to a known vacuum (26-34 kPa). 3) Checks MAP sensor's ability to react to sudden change in vacuum.

Fig. 150: Code P071 Schematic - 1 Of 2, Intermittent MAP Sensor Signal Courtesy of General Motors Corp.

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Fig. 151: Code P071 Schematic - 2 Of 2, Intermittent MAP Sensor Signal Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 191)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 152: Code P071 Diag. Flow Chart, Intermittent MAP Sensor Signal Courtesy of General Motors Corp.

CODE P073, INTERMITTENT ENGINE COOLANT TEMP SENSOR SIGNAL

Engine Coolant Temperature (ECT) sensor circuit uses 2 pullup resistors for temperature sensing. When sensor resistance is high (indicating low temperatures), PCM uses 3.65-k/ohm resistor and 348ohm resistor in series. As temperature increases to 122øF (50øC), sensor resistance will decrease to 973 ohms. This resistance corresponds to .97 volt at PCM. At this point PCM shifts to single 348-ohm pull-up resistor to measure temperature greater than 122øF (50øC). PCM monitors voltage signal of circuit and assumes engine operation causes coolant temperatures to change at slow rates. This test monitors ECT sensor voltage. If PCM detects a large change in sensor output voltage in a one-second period, code will set. Test Conditions Two seconds have passed since ignition has been turned on and 2 seconds have passed since PCM had shifted ECT sensor pull-up resistors. This occurs when sensor resistance indicates 122øF (50øC). Failure Conditions ECT sensor voltage changes .3 volt in one second. Action Code P073 is set. No service message is given. NOTE:

Test number refers to number on diagnostic chart. Reference to CHART 3 refers to POWERTRAIN CHARTS.

1) Checks Code P073 snapshot value to determine if an intermittent high or low resistance caused code to set. An intermittent high resistance can be caused by an open in circuit No. 410 or 808. An intermittent low resistance can be caused by a short to ground in circuit No. 410.

G - TESTS W/CODES - 4.6LArticle Text (p. 192)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 153: Code P073 Schematic, Intermittent Engine Coolant Temperature Sensor Signal Courtesy of General Motors Corp.

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G - TESTS W/CODES - 4.6LArticle Text (p. 194)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 154: Code P073 Diagnostic Flow Chart, Intermittent Engine Coolant Temperature Sensor Signal Courtesy of General Motors Corp. CODE P074, INTERMITTENT IAT SENSOR SIGNAL

Code P074 will set when PCM detects a large change in sensor output voltage in a .3-second period of time. Test Conditions Two seconds have passed since ignition switch has been

turned to RUN position. Failure Conditions IAT sensor voltage changes .3 volt (11øC) in 250 milliseconds. Action None. NOTE:

Test number refers to number on diagnostic chart. Reference to CHART 3 refers to POWERTRAIN CHARTS.

1) Checks Code P074 snapshot to determine if an intermittent high or low resistance caused code to set. An intermittent high resistance can be caused by an open in circuit No. 452 or 472. An intermittent low resistance can be caused by a short to ground on circuit No. 472.

Fig. 155: Code P074 Schematic, Intermittent IAT Sensor Signal Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.

Fig. 156: Code P074 Diagnostic Flow Chart, Intermittent IAT Sensor Signal Courtesy of General Motors Corp. CODE P075, VSS SIGNAL INTERRUPT

This test compares vehicle speed to manifold pressure. Change in MAP must correspond with a change in vehicle speed. PCM will ignore test if conditions for engine idle are present. If vehicle speed changes 14 MPH (VIN Y) or 16 MPH (VIN 9) or greater in one second Code P075 will set. If failure occurs 10 times in 10 seconds, code will remain current for the entire ignition cycle. Test Conditions Codes P021, P022, P027, P056 and P090 not set. TCC brake switch not applied. Engine running at 500 RPM or greater. Two seconds have passed since ignition was turned on. Traction control not active. Throttle position 15.7 degrees or greater.

Failure Conditions Vehicle speed change of 4 MPH or more in a one-second time period. G - TESTS W/CODES - 4.6LArticle Text (p. 196)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Action PCM turns on MIL, disables TCC and freezes transaxle in current gear. If failure occurs 10 times in 10 seconds, code will

remain current for the entire ignition cycle.

Fig. 157: Code P075 Schematic, VSS Signal Interrupt Courtesy of General Motors Corp. CODE P076, TRANSAXLE PRESSURE CONTROL SOLENOID CIRCUIT

Transaxle pressure control solenoid regulates pressure to maintain a desired transaxle line pressure under varying operating conditions. PCM send a pulse width modulated signal to transaxle pressure control solenoid in order to control line pressure. A PCM internal current monitor is provided as feedback to determine actual transaxle pressure control solenoid current draw. Current draw is proportional to transaxle line pressure. If commanded versus actual current draw is different by more than calibrated value or if transaxle pressure control solenoid is energized at 100 percent duty cycle for 3 minutes or more, Code P076 will set. Test Conditions Codes P016, P086 and P089 not set. Engine running.

Failure Conditions Difference between commanded and actual transaxle pressure control solenoid current .16 amps or greater for one second or transaxle pressure solenoid energized at 100 percent duty cycle for 3 minutes or more. G - TESTS W/CODES -

Action PCM turns on MIL, transaxle pressure control solenoid deenergized. Torque management disabled and transaxle shift adapts are maintained at current levels. NOTE:

Test number refers to number on diagnostic chart.

1) Checks for open in transaxle pressure control solenoid circuit. If resistance is 8 ohms or greater, circuit is open. 2) Checks for short to ground in transaxle pressure control solenoid circuit. If resistance is 100 ohms or less, circuit is shorted to ground. 3) If transaxle pressure control solenoid is okay, fault is either intermittent or PCM is faulty. 4) If resistance is greater than 8 ohms, check for open transaxle pressure control solenoid or circuits No. 1228 or 1229. If resistance is 8 ohms or less, check for open between solenoid connector and PCM in circuits No. 1228 or 1229. 5) If resistance is 100 ohms or greater, check for short to ground between PCM connector circuits NO. 1228 or 1229. If resistance is less than 100 ohms, check for short to ground inside transaxle circuits No. 1228 or 1229 or for shorted transaxle pressure solenoid.

Fig. 158: Code P076 Schematic, Transaxle Pressure Control Solenoid Circuit Courtesy of General MotorsText Corp. G - TESTS W/CODES - 4.6LArticle (p. 198)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 159: Code P076 Diagnostic Flow Chart, Transaxle Pressure Control Solenoid Circuit Courtesy of General Motors Corp. CODE P080, TP SENSOR/IDLE LEARN NOT COMPLETE

G - TESTS W/CODES - 4.6LArticle Text (p. 199)1995 Cadillac Concours

This test checks if initial TP sensor learn and idle learn values have been stored in PCM. If these values have not been stored, Code P080 is set. Performing TP sensor/idle learn procedure will cause Code P080 to become history. Test Conditions Tested continuously. Failure Conditions No TP sensor or idle learn value stored. Actions PCM turns on MIL.

Fig. 160: Code P080 Schematic, TP Sensor/Idle Learn Not Complete Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 200)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 161: Code P080 Diag. Flow Chart, TP Sensor/Idle Learn Not Complete Courtesy of General Motors Corp. CODE P081, CAM TO 4X REFERENCE CORRELATION PROBLEM

This test checks to see if there are eight 4X reference pulses between cam signals. Code P081 will set when this signal is not present. DO NOT attempt diagnosis or repair unless vehicle operator is Cadillac ConcoursFor Ace Mechanics G - TESTS W/CODES - 4.6LArticle Text (p. 201)1995 experiencing driveability problems associated with this code. 123 Main Street San Diego Ca 92 Test Conditions Code P035 not set, engine speed greater than 496 RPM and 7 or greater cam pulses after ignition was turned on. Failure Conditions Number of 4X reference pulses between cam pulses is not equals to 8. Failure must exist continuously for 2 or more cycles.

Action None.

Fig. 162: Code P081 Schematic, CAM To 4X Reference Correlation Problem Courtesy of General Motors Corp.

Fig. 163: Code P081 Schematic, CAM To 4X Reference Correlation Problem Courtesy of General Motors Corp.

G - TESTS W/CODES

CODE P083, 24X REFERENCE SIGNAL HIGH

This test checks for 24X signal at a logic high condition. Fault can be induced by failure of either crankshaft position sensor "A" or "B" input signal to ignition control module. Under such condition, ignition control module would force the 24X signal high. This test also checks for 24X shorted to battery externally. Code P083 will set if either conditions are met. Test Conditions Code P035 not set. Engine speed greater than 496 RPM but less than 1200 RPM. 7 or more cam pulses received since ignition was turned on and ignition control not in by-pass mode. Failure Conditions 24X signal at logic HI and no 24X reference pulses received since last cam pulse. Actions PCM turns on MIL. NOTE:

Test number refers to number on diagnostic chart.

1) Checks if Code P035 is set. REF LO problem can cause other ignition problem. 2) If engine stalls, problem is with crankshaft sensor "B". Engine will continue running with only one crankshaft sensor. 3) Checks crankshaft position "B" sensor for open or shorted circuit. Resistance should be 800-1600 ohms. 4) Checks if circuits No. 470 or 1800 is shorted to ground. If circuit is shorted to ground, resistance will be less than 100 ohms. 5) Sensor is okay if it is able to produce a DC voltage greater than 0.25. 6) If engine stalls, problem is with crankshaft position sensor "A". If engine remains running, ignition module or circuit No. 647 is shorted. 7) Checks crankshaft position sensor "A" circuit for open or short. Resistance should be 800-1600 ohms. 8) Checks if circuit No. 573 or 574 is shorted to ground. If circuit is shorted to ground, resistance will be less than 100 ohms. 9) If sensor is able to produce a DC voltage of greater than .25 volt, sensor is okay. 10) Checks if circuit No. 647 is shorted high or if ICM is keeping high. If reading is greater than zero Hertz, ICM and circuit NO. 647 are okay. Check for intermittent fault.

G - TESTS W/CODES - 4.6LArticle Text (p. 203)1995 Cadillac Concours

Fig. 164: Code P083 Schematic, 24X Reference Signal High Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 204)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 205)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 165: Code P083 Diag. Flow Chart - 1 Of 2, 24X Reference Signal High Courtesy of General Motors Corp.

Fig. 166: Code P083 Diag. Flow Chart - 2 Of 2, 24X Reference Signal G - TESTS W/CODES - 4.6LArticle Text (p. 206)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 High Courtesy of General Motors Corp. CODE P085, IDLE THROTTLE ANGLE TOO HIGH

PCM continuously learns base idle position. This base idle position is the relationship of engine RPM to throttle position. PCM is limited to a fixed amount of learned throttle angle that it can apply. When this limit is reached, Code P085 will set. The cause of this increase in learned throttle angle is usually deposits in throttle body. Test Conditions Constantly monitored. Failure Conditions A/C on or off, learned idle throttle angle 3.9 degrees or greater. Action PCM turns on MIL. NOTE:

Test number refers to number on diagnostic chart.

1) Checks for other throttle position sensor codes being set, causing other throttle body problems. 2) Checks if throttle body deposits are causing the increase in learned throttle angle. Check for loose fitting air duct or air cleaner causing debris to enter throttle body. 3) Checks if ISC motor can retract far enough to close throttle position switch. 4) Checks for proper operation of ISC motor. Notes On Intermittents PCM Code P085 may set due to an engine overheated condition in which PCM will only allow engine to run on 4 cylinders, causing a high idle throttle angle. If this occurs, clear PCM Code P085, reset idle learn using PCM override PS13 and perform TP sensor/idle learn.

G - TESTS W/CODES - 4.6LArticle Text (p. 207)1995 Cadillac Conco

Fig. 167: Code P085 Schematic, Idle Throttle Angle Too High Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 208)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 209)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 168: Code P085 Diagnostic Flow Chart, Idle Throttle Angle Too High Courtesy of General Motors Corp. CODE P086, UNDEFINED GEAR RATIO

Transaxle gear ratio is calculated from ratio of turbine speed against output speed. This test checks gear ratio which is not possible to obtain under normal operating condition of transaxle, if such gear ratio is observed, Code P086 is set. Test Conditions Codes P021, P022, P024, P056 and P075 not set. Engine running and vehicle speed at 7 MPH or greater. Throttle position at 11

degrees or greater. Transaxle not in Park or Neutral and commanded transaxle line pressure 100 psi or greater.

* * * * *

Failure Conditions: Gear ratio less than Gear ratio less than Gear ratio less than Gear ratio less than Gear ratio less than

2.87 1.54 0.95 0.65 2.07

or or or or or

greater greater greater greater greater

than than than than than

3.11 1.71 1.05 0.71 2.23

for for for for for

3 3 3 3 3

seconds. seconds. seconds. seconds. seconds.

Action PCM turns on MIL. PCM de-energizes transaxle pressure control solenoid and torque management is disabled. Maintains transaxle shift adapts at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Install pressure gauges to transaxle. 2) Comparing gear box ratio (PD76) and transaxle pressure switch input (PD71) will determine what gear PCM was commanding and what possible gear ratio change resulted from such command.

Fig. 169: Code P086 Schematic, Undefined Gear Ratio Courtesy of General Motors Corp.

G - TESTS W/CO

Fig. 170: Code P086 Diagnostic Flow Chart - 1 Of 2, Undefined Gear Ratio Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 211)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 212)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 171: Code P086 Diagnostic Flow Chart - 2 Of 2, Undefined Gear Ratio Courtesy of General Motors Corp.

CODE P088, TCC NOT DISENGAGING

This test checks for TCC slippage. If slippage is not present when transaxle is operating at a given condition, TCC is engaged. Test Conditions Codes P021, P022, P028 and P056 not set. Engine running and throttle position at 15.7 degrees or greater. Transaxle in 3rd or 4th gear. Failure Condition Slip speed at less than 5 or equals to 10 RPM for 4 seconds (slip = engine RPM - transaxle RPM). Action PCM turn on MIL and freezes shift adapts from being updated. TCC disabled. Action PCM turn on MIL. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks circuit harness connector C129 and 2) Isolates short 3) Checks circuit transaxle.

No. 422 (Tan/Black wire) between engine PCM connector 3E13 for short to ground. to ground between engine harness or PCM. No. 422 for short to ground inside

G - TESTS W/CODES - 4.6LArticle Text (p. 213)1995 Cadillac Concours

Fig. 172: Code P088 Schematic, TCC Not Disengaging Courtesy of General MotorsText Corp. G - TESTS W/CODES - 4.6LArticle (p. 214)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 173: Code P088 Diagnostic Flow Chart, TCC Not Disengaging Courtesy of General Motors Corp.

CODE P089, LONG SHIFT AND MAXIMUM ADAPT

Transaxle pressure is modified by an adaptive modifier used to control gear shift execution time. This test checks the shift extension and time it takes to accomplish it. If it takes longer than .55 second and adaptive modifier cannot shorten this time, counter will increment. When counter reaches 5, Code P089 will set. Test Conditions Codes P021, P022, P024, P056, P057, P059 and P075 not set. Vehicle speed at 10 MPH or greater and throttle position is at 15.7 degrees or greater. Transaxle temperature at 194øF (90øC) or greater. * * *

Failure Conditions: 1-2 shift time 5.5 seconds or greater and adapt cannot shorten shift time for 5 shifts. 2-3 shift time 5.5 seconds or greater and adapt cannot shorten shift time for 5 shifts. 3-4 shift time 5.5 seconds or greater and adapt cannot shorten shift time for 5 shifts. Action PCM turns on MIL and de-energizes transaxle pressure control

solenoid. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) 2) the code to 3) which shift

Install transaxle pressure gauge. Using operator information to diagnose which shift caused set. Code P089 snapshot information can be used to determine the long time occurred on.

Notes On Intermittents Due to complexity of the 4T80-E transaxle, an intermittent PCM Code P089 will be very difficult to diagnose. Hold off maintenance until specific problem is identified.

G - TESTS W/CODES - 4.6LArticle Text (p. 215)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 174: Code P089 Schematic, Long Shift And Maximum Adapt Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 216)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 217)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 175: Code P089 Diagnostic Flow Chart - 1 Of 2, Long Shift And Maximum Adapt Courtesy of General Motors Corp.

Fig. 176: Code P089 Diagnostic Flow Chart - 2 Of 2, Long Shift And Maximum Adapt Courtesy of General Motors Corp. CODE P090, TCC BRAKE SWITCH INPUT CIRCUIT PROBLEM

Cadillac ConcoursFor Mechanics decrease 123 Main Street San Diego Ca 92 G - TESTS W/CODES This test - 4.6LArticle functions Text on (p. 218) the1995 assumption that Ace a sudden in wheel speed on the non-drive wheel is caused by a brake application. Non-drive wheel speed and stoplight switch status are supplied to PCM through the serial data from Electronic Brake and Traction Control Module (EBTCM).

Test Conditions Codes P033, P106 and P137 not set. Traction control and anti-lock brake system operating normally. Non-drive wheel speed of 36 MPH or greater and has not fallen to less than 1.2 MPH. Failure Conditions A 1.8 MPH or greater decrease in non-drive wheel speed in 0.2 second. Transition in the extended travel brake contacts of TCC brake switch or stop/BTSI/cruise brake switch. No transition noticed in TCC contacts of TCC brake switch. Counter increments if these conditions are present. When counter reached 5, Code P090 sets. Action Traction control disabled. PCM disables cruise control and substitutes status of stop/BTSI/cruise brake switch input for TCC brake switch input. "TRACTION DISABLED" and "REDUCED ENGINE POWER" message displayed on DIC. Garage shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Testing TCC brake switch input to PCM PI71. If input is working correctly, display will change from HI to LO to HI. If display remains HI, check circuit No. 420 and TCC brake switch for short to voltage. If display remains LO, check circuit No. 420 for open or short to ground. 2) Checks for voltage at TCC brake switch terminal "A". 3) Checks circuit No. 741 for short to ground. 4) Checks circuit No. 420 for short to ground. If circuit is okay, check circuit No. 741 for open. 5) Checks circuit No. 420 for open.

G - TESTS W/CODES - 4.6LArticle Text (p. 219)1995 Cadillac Concours

Fig. 177: Code P090 Schematic, TCC Brake Switch Input Circuit Problem Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 220)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 221)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 178: Code P090 Diagnostic Flow Chart, TCC Brake Switch Input Circuit Problem Courtesy of General Motors Corp. CODE P091, TRANSAXLE RANGE SWITCH PROBLEM

This test monitors closing of transaxle range switch when vehicle is in gear or an engine start while transaxle range switch is open (not in P/N).

Test Condition 1 Vehicle not moving. Test Condition 2 Gear ratio indicating P/N range. Failure Conditions 1 Engine speed changes from zero to higher RPM without P/N input to PCM HI (not in P/N). At least 5 seconds have elapsed since transaxle switch was moved. Failure Conditions 2 Codes P024, P075 and P086 not set. P/N input to PCM LO (in P/N). Engine running and throttle position 15.7 degrees or greater. Vehicle speed at 7 MPH or greater. Gear ratio of 3.11 or less (vehicle in gear). All these conditions happened within 5 seconds. Actions PCM turns on SERVICE VEHICLE SOON light. PCM disables cruise control and will substitute gear status from transaxle pressure switch for transaxle range switch. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks PCM status light. AUTO should be displayed when gearshift is in Park or Neutral and OFF should be displayed if gearshift is in any other gear. 2) Checks transaxle range switch for open. 3) Checks circuit No. 451 for open. 4) Checks circuit No. 434 for open. 5) Checks if fault is still present. 6) Checks for shorted transaxle range switch. 7) Checks circuit No. 434 for short to ground. Note On Intermittents Check for intermittent short to ground in circuit No. 434. A stall or a near stall condition which may set Code P054 or P095 and may cause a false Code P091 to set due to engine transition from running to not running (or near stall) then back to running without transaxle switch being in Park or Neutral.

G - TESTS W/CODES - 4.6LArticle Text (p. 222)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 179: Code P091 Schematic, Transaxle Range Switch Problem Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 223)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 224)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 180: Code P091 Diagnostic Flow Chart, Transaxle Range Sw. Problem Courtesy of General Motors Corp. CODE P092, HEATED WINDSHIELD REQUEST PROBLEM

This test will detect a problem with heated windshield fast idle request circuit to PCM. When circuit is grounded by heated windshield module, PCM will increase idle speed to compensate for extra load placed on alternator. Code P092 will set when signal is low for more than 10 minutes. Test Conditions Engine running.

Failure Conditions Heated windshield request present at PCM for more than 10 minutes. Action Code set. PCM turns on SERVICE VEHICLE SOON message.

Fig. 181: Code P092 Schematic, Heated Windshield Request Problem Courtesy of General Motors Corp.

Fig. 182: Code P092 Diag. Flow Chart, Heated Windshield Request Problem G - TESTS W/CODES - 4.6LArticle (p. 225)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Courtesy of General MotorsText Corp.

CODE P093, TRACTION CONTROL SYSTEM PWM LINK FAILURE

This test checks for traction control system PWM link failure to PCM. Test Conditions Code P137 not set. Traction control not failed. Failure Conditions No rising edges of traction control system PWM signals are received for 3 seconds. Action TRACTION DISABLED message displayed in DIC. PCM disables 1st gear and transaxle shift adapts are maintained at current levels. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks for traction control communication code that was set. Determines if it is a PCM problem or not. 2) Checks for proper output voltage from PCM. 3) Checks circuit No. 594 for open. 4) Checks circuit No. 594 for short to ground. 5) Checks circuit No. 594 for short to voltage. 6) Checks for intermittent traction control problem. If traction control system is okay, check for faulty PCM or EBTCM.

Fig. 183: Code P093 Schematic, Traction Control System PWM Link Failure Courtesy of General Motors Corp.G - TESTS W/CODES - 4.6LArticle Text (p. 226)1995 Cadillac Concours

Fig. 184: Code P093 Diagnostic Flow Chart, Traction Control System PWM Link Failure Courtesy of General Motors Corp. CODE P094, TRANSAXLE SHIFT SOLENOID "A" PROBLEM

G - TESTS W/CODES - 4.6LArticle Text (p. 227)1995 Cadillac Concours

Monitors commanded gear versus transaxle gear ratio to check transaxle shift solenoid "A". If gear ratio falls out of range for a given gear, Code P094 will set. Test Conditions Codes P021, P022, P024, P028 and P056 not set. Transaxle pressure switch indicating transaxle in D1, D2, D3 or D4 position. Engine running and vehicle speed at 7 MPH or greater. Throttle position at 11 degrees or greater. Failure Conditions: * * * *

Gear ratio commanded. Gear ratio commanded. Gear ratio commanded. Gear ratio commanded.

between 1.54-1.71 for 5 seconds, 1st gear between 2.87-3.11 for 5 seconds, 2nd gear between 0.67-0.71 for 5 seconds, 3rd gear between 0.95-1.05 for 5 seconds, 4th gear

Action PCM turns on MIL. PCM allows only 2nd gear when forward gear is selected. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if Code P117 is set. Presence of code will cause transaxle problem. 2) Checks if shift solenoid "A" is HI when it be LO or viceversa. 3) Checks if PCM is operating correctly and setting a false code. 4) Checks if circuit No. 741 is open at connector. 5) Checks if circuit No. 1222 (engine harness side) is open. 6) Checks if circuit No. 1222 (trans. harness side) is shorted to ground inside transaxle. 7) Checks for an open circuit inside transaxle. 8) Checks if circuit No. 1222 (trans. harness side) for short to voltage inside transaxle. 9) Checks if circuit No. 1222 (engine harness side) for short to voltage from connector to PCM. 10) Checks for possible cause for getting 4th gear when 3rd gear is commanded. 11) Checks for possible cause for getting 3rd gear when 4th gear is commanded. 12) Checks for possible cause for getting 2nd gear when 1st gear is commanded. G - TESTS W/CODES - 4.6LArticle Text (p. 228)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

13) Checks for possible cause for getting 1st gear when 2nd gear is commanded.

Fig. 185: Code P094 Schematic, Transaxle Shift Solenoid "A" Problem Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 229)1995 Cadillac ConcoursFor Ace Mechanics 123

G - TESTS W/CODES - 4.6LArticle Text (p. 230)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 186: Code P094 Diagnostic Flow Chart - 1 Of 2, Transaxle Shift Solenoid "A" Problem Courtesy of General Motors Corp.

Fig. 187: Code P094 Diagnostic Flow Chart - 2 Of 2, Transaxle Shift Solenoid "A" Problem Courtesy of General Motors Corp.

CODE P095, ENGINE STALL OR NEAR STALLGDETECTED - TESTS W/CODES - 4.6LArticle Text (p. 231)1995 Cadillac Concours

This test checks for an engine stall or near stall and sets Code P095 is a stall condition is detected. A partial start where engine RPM exceeds 400 RPM and engine does not start will also cause Code P095 to set. This code is designed to capture snapshot data of the stall condition. This code may also set as the ignition is turned off if injectors or ICM looses power before the PCM. Test Conditions Ignition on. Failure Conditions Engine speed drops to less than 152 RPM after exceeding 400 RPM this ignition cycle. No reference pulses have been received for 7. 5 seconds. Action None.

Fig. 188: Code P095 Schematic, Engine Stall Or Near Stall Detected Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 232)1995 Cadil

Fig. 189: Code P095 Diagnostic Flow Chart, Engine Stall Or Near Stall Detected Courtesy of General Motors Corp. CODE P096, TORQUE CONVERTER OVER STRESS

G - TESTS W/CODES - 4.6LArticle Text (p. 233)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 Primary purpose of Code P096 is to detect an action of driver which could cause an unsafe condition or damage to vehicle. Code P096 can be driver-induced by application of brake and accelerator at same time.

Test Conditions Codes P021, P022 and P024 not set. Failure Conditions Brake applied, transaxle in Drive or Reverse, vehicle speed 5 MPH or less and throttle angle greater than 65 degrees for 12 seconds. Action Code P096 is set. PCM turns on MIL.

Fig. 190: Code P096 Schematic, Torque Converter Over Stress Courtesy of General Motors Corp. CODE P097, PARK/NEUTRAL-TO-DRIVE/REVERSE SHIFT AT HIGH

THROTTLE ANGLE Primary purpose of Code P097 is to detect an action of vehicle operator which could cause an unsafe condition or damage to vehicle. When such conditions exists, Code P097 is set and engine power will be reduced by disabling fuel injector to individual cylinders. Test Conditions Codes P021 and P022 not set.

G - TESTS W/CODES - 4.6LArticle Text (p. 234)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Dieg

Failure Conditions Engine speed greater than 2000 RPM, gear selector moved from Park or Neutral to Drive or Reverse, vehicle speed less than 6 MPH and throttle angle is 20 degrees or greater. Action "REDUCED ENGINE POWER" message displayed on DIC. PCM will disable selected injectors to reduce engine power and set Code P097.

Fig. 191: Code P097 Schematic, Park/Neutral-To-Drive/Reverse Shift At High Throttle Angle Courtesy of General Motors Corp. CODE P099, CRUISE SERVO APPLIED NOT IN CRUISE

This diagnostic test monitors cruise control servo position sensor to ensure servo has released throttle after cruise control has been disengaged for 2 seconds. If cruise control servo has not been released, Code P099 will set and engine power will be reduced by disabling fuel to individual cylinders. Code P068 may disable cruise control and lead to setting Code PCM P099. G - TESTS W/CODES - 4.6LArticle Text (p. 235)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Test Conditions Engine running. Code PS07 override not active. Failure Conditions Failure conditions for PCM code set change depending on whether code was previously set or not. Code P099 not previously set: * * * *

Cruise control disengaged for 2 seconds. Throttle angle greater than 20 degrees, TP sensor not failed. MAP greater than 70 kPa, TP sensor failed. Cruise control servo stroke greater than 63 percent for 0.1 second. Code P099 previously set:

* * * *

Cruise control disengaged for 2 seconds. Throttle angle greater than 16 degrees, TP sensor not failed. MAP greater than 55 kPa, TP sensor failed. Cruise control servo stroke greater than 37 percent for 0.1 second.

Action REDUCED ENGINE POWER displayed on DIC. PCM disables cruise control and reduces fuel delivery to selected cylinders. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if PCM can control cruise control solenoid. 2) Checks if cruise control position sensor is working correctly. 3) Checks if cruise control servo will extend fully. If servo does not extend fully, check circuit No. 402 for a short to voltage. Note On Intermittent Code P099 may be inadvertently induced by technician using cruise servo to bump up throttle.

G - TESTS W/CODES - 4.6LArticle Text (p. 236)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 192: Code P099 Schematic, Cruise Servo Applied Not In Cruise Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 237)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 193: Code P099 Diag. Flow Chart, Cruise Servo Applied Not In Cruise Courtesy of General Motors Corp.

CODE P102, SHORTED BRAKE BOOSTER VACUUM (BBV) SENSOR

Brake booster vacuum sensor changes resistance based on vacuum inside brake booster. This test checks for a vacuum reading which can be caused by a shorted sensor or a short on circuit No. 1726 or and open on circuit No. 808. Every time TCC brake switch cycles from closed to open with engine not at idle, this test checks for a shorted vacuum signal. If shorted vacuum signal is detected for 5 consecutive cycle of TCC brake switch, Code P102 will set. Any cycle of TCC brake switch where a shorted vacuum signal is not detected will reset counter to zero. Test Conditions Codes P031, P032, P034, P071 and P090 not set. One second has passed since TCC brake switch was cycled from closed to open. MAP value at 30 kPa or greater (engine not at idle) for one second. Failure counter will increment when all these conditions are present and brake booster vacuum signal is 82 kPa or greater. Failure counter will reset when all these conditions are present but vacuum signal is less than 82 kPa. Failure Conditions Failure counter at 7 counts or greater. Action PCM turns on SERVICE VEHICLE SOON message. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) PCM data PD84 will read 82-84 kPa with sensor shorted. If reading is not as specified, fault is not present. 2) If PCM data PD84 reads -11 to -8 kPa with sensor unplugged, check circuit No. 476 for open or for a shorted sensor. 3) Checks circuit No. 1726 for short to voltage.

G - TESTS W/CODES - 4.6LArticle Text (p. 238)1995 Cadillac Concours

Fig. 194: Code P102 Schematic, Shorted Brake Booster Vacuum (BBV) Sensor Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 239)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 195: Code P102 Diagnostic Flow Chart, Shorted BBV Sensor Courtesy of General Motors Corp.

CODE P103, OPEN BRAKE BOOSTER VACUUM (BBV) SENSOR

Brake booster vacuum sensor changes resistance based on vacuum inside brake booster. This test checks for a vacuum reading which can be caused by an open sensor or open on circuit No. 474 or and short to ground on circuit No. 1726. When PCM detects as brake booster vacuum signal that is too low, Code P103 will set. Test Conditions Tested continuously. Failure Conditions Failure counter at 7 counts or greater. Action PCM turns on SERVICE VEHICLE SOON message. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If brake booster vacuum sensor is open PD84 should read -8 kPa or less. 2) If brake booster vacuum sensor is open, PD84 should read 82-84 kPa with sensor terminals jumpered together. 3) Checks circuit No. 1726 for short to ground between BBV and PCM. 4) Checks circuit No. 1726 for open between BBV and PCM.

Fig. 196: Code P103 Schematic, Open Brake Booster Vacuum (BBV) Sensor Courtesy of General Motors Corp. G - TESTS W/CODES - 4.6LArticle Text (p. 240)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 197: Code P103 Diagnostic Flow Chart, Open BBV Sensor Courtesy of General Motors Corp. CODE P105, BRAKE BOOSTER VACUUM (BBV) SENSOR TOO LOW

Brake booster vacuum sensor changes resistance based on vacuum inside brake booster. This test monitors brake booster vacuum along with manifold vacuum. If brake booster vacuum is too low for a given manifold vacuum and brakes are not applied, then brake booster vacuum signal must be in error and will set Code P105. Test Conditions Codes P031, P032, P034, P071, P103 and P137 not set. Engine speed at 500 RPM or greater for 20 seconds and brake not applied. Barometric pressure at 72 kPa or greater and MAP at 60 kPa or less. Failure Conditions Brake booster vacuum 5 kPa or less for 16 seconds.

Action G - TESTS W/CODES - 4.6LArticle Text (p. 241)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

PCM turns on SERVICE VEHICLE SOON message. NOTE:

Test numbers refer to numbers on diagnostic chart. 1) Diagnose Code P103 first because it can cause other BBV

problems. 2) If brake booster vacuum signal is too low, PD84 will be less than 5 kPa or less. If not, signal is too low. 3) Checks for vacuum leaks that are causing low signal. 4) With BBV sensor terminals "B" and "C" jumpered together, PD84 should read greater than 81 kPa. If reading is not as specified, check circuit No. 1726 for short to ground. 5) If resistance is less than 500 ohms, check circuit for short to ground. 6) If resistance is less than 10,000 ohms, check circuit for short to ground.

Fig. 198: Code P105 Schematic, Brake Booster Vacuum (BBV) Sensor Too Low Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 242)1995 Cadillac ConcoursFor Ace Mechanics 123 Main

1995Chart, Cadillac ConcoursFor Ace Mechanics Fig. 199: Code P105 Diagnostic Flow BBV Sensor Too Low123 Main Street San Diego Ca 92 G - TESTS W/CODES - 4.6LArticle Text (p. 243) Courtesy of General Motors Corp. CODE P106, STOPLIGHT SWITCH INPUT CIRCUIT PROBLEM

This test functions on the assumption that a sudden decrease in wheel speed on the non-drive wheel is caused by a brake

application. Non-drive wheel speed and stoplight switch status are supplied to PCM through the serial data from Electronic Brake and Traction Control Module (EBTCM). Test Conditions Codes P033, P090 and P137 not set. Traction control and ABS are operating normally and non-drive wheel speed at 36 MPH or greater. Failure Conditions A 1.8 MPH or greater decrease in non-drive wheel speed in 0.2 second. Transition in TCC or extended travel contacts of TCC brake switch or no transition of stop/BTSI/cruise brake switch noticed. If these conditions are met, trouble code will set. Action Traction control disabled. PCM will set stop/BTSI/cruise brake switch status not applied. TRACTION DISABLED and REDUCED ENGINE POWER message displayed. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if PCM input test PI89 will cycle when brake pedal is depressed and released. If PI89 remains HI, check fro short to voltage in system. If P189 remains LO, check for open or short to ground in system. 2) Checks for voltage supplied to brake switch. 3) Checks circuit No. 540 for short to ground. 4) Checks circuit No. 20 for short to ground. 5) Checks circuit No. 20 for open or for faulty PCM.

Fig. 200: Code P106 Schematic, Stoplight Switch Input Circuit Problem Courtesy of General Motors Corp. G - TESTS W/CODES - 4.6L

Fig. 201: Code P106 Diagnostic Flow Chart, Stoplight Switch Input Circuit Problem Courtesy of General Motors Corp. CODE P110, ALTERNATOR "L" TERMINAL CIRCUIT PROBLEM

This test monitors alternator feedback and compares it to alternator control in PCM. When PCM commands alternator turned on and feedback indicates that it is off for 15 seconds, Code P110 will set. G - TESTS W/CODES 12 - 4.6LArticle Textalternator (p. 245)1995 Cadillac Concours PCM initiates alternator operation by supplying volts to

"L" terminal through circuit No. 225. Alternator regulator applies voltage to rotor as pulse signal to energize the field windings. Alternator can detect internal faults, setting Code P110. It can also self-diagnose a shorted output diode, malfunctioning regulator, open or shorted rotor, over or under voltage condition, shaft not rotating or open sense lead. Test Conditions Engine running. PCM commanding alternator on. Failure Conditions PCM commanding alternator on and alternator feedback indicating it is off for 15 seconds. Action BATTERY NO CHARGE message displayed on DIC. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks PCM's ability to cycle alternator control output. If voltage cycles, replace battery. 2) Checks if circuit No. 225 is open or shorted to ground or if PCM is faulty. Notes On Intermittents A loose or faulty connection at alternator "L" terminal may cause Code P110 to set intermittently.

Fig. 202: Code P110 Schematic, Alternator "L" Terminal Circuit Problem Courtesy of General Motors Corp.

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Fig. 203: Code P110 Diagnostic Flow Chart, Alternator "L" Terminal Circuit Problem Courtesy of General Motors Corp. CODE P112, EEPROM FAILURE

Electrically Erasable Programmable Read Only Memory (EEPROM) is used by PCM to store data even when battery power is removed. It stores TP sensor/idle learned values, transaxle adapt values, transaxle oil life index and cruise control lash/learn. EEPROM store this information in several locations and if PCM detects a problem in one location of EEPROM, it will store data in another location. If PCM runs out of good locations in the EEPROM to store data, Code P112 will be stored. PCM stores the same data in its Keep Alive Memory so that even if EEPROM is bad, Code P112 will set. Vehicle operation will remain unchanged. Even after a code is set, PCM will continue to look for good locations in the EEPROM to store data. If a good location is found, Code P112 will become a history code. If Code P112 is present, PCM must be replaced. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) If Code P112 is set current, PCM cannot find another location to store data. Replace PCM. 2) Cycle ignition to PCM a chance to find a place to store data. If trouble code resets, PCM must be replaced.

G - TESTS W/CODES - 4.6LArticle Text (p. 247)1995 Cadillac Concours

Fig. 204: Code P112 Schematic, EEPROM Failure Courtesy of General Motors Corp. CODE P117, SHORTED/OPEN SHIFT SOLENOIDS "A" & "B" CIRCUIT

This test monitors the shift "A" and "B" outputs from PCM and increments a counter when output is different than what it is commanded. When counter reaches 10, Code P117 sets. If at any time counter reaches 10 but output is the same as commanded, counter will reset to zero. Test Conditions Closed loop fuel control is enabled Failure Conditions Shift solenoids "A" and "B" output is different than what is commanded 10 consecutive times. Action PCM turns on MIL. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if Code P029 is also present, indicating a shift solenoid "B" problem. 2) Checks if Code P049 is also present, indicating a shift solenoid "A" problem. 3) Checks which gear is selected when fault occurs to determine possible faults. 4) Checks for short to voltage in circuit No. 1222 by looking at gear ratio when troubleText code was1995 set. Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 G - TESTS W/CODES - 4.6LArticle (p. 248) 5) Checks circuit No. 741 and fuse D1 for open.

6) Checks circuits No. 741 and 1222 (transaxle harness side) or transaxle shift solenoid "A" for open. 7) Checks for short to ground. If resistance is 1000 ohms or less, short is inside transaxle. If resistance is greater than 1000 ohms, short is between solenoid connector and PCM. 8) Checks for short to voltage in circuit No. 1223 by looking at gear ratio when trouble code was set. 9) Checks circuit No. 741 and fuse D1 for open. 10) Checks circuits No. 741 and 1223 or transaxle shift solenoid "B" for open. 11) Checks for short to ground. If resistance is 1000 ohms or less, short is inside transaxle. If resistance is greater than 1000 ohms, short is between solenoid connector and PCM. 12) Checks if shift solenoid "A" is functioning properly using PCM output and PCM status light. 13) Checks if shift solenoid "B" is functioning properly using PCM output and PCM status light. 14) Checks if PCM is receiving voltage. 15) Checks for open or short to ground on circuit No. 741 outside of transaxle. 16) Checks circuits No. 741 and 1222 or shift solenoid "A" for open. 17) Checks for short to ground. If resistance is equal to or less than 1000 ohms, short is inside transaxle. If resistance is greater than 1000 ohms, short is between harness connector and PCM. 18) Checks circuits No. 741 and 1223 or shift solenoid "B" for open. 19) Checks for short to ground. If resistance is equal to or less than 1000 ohms, short is inside transaxle. If resistance is greater than 1000 ohms, short is between harness connector and PCM.

G - TESTS W/CODES - 4.6LArticle

Fig. 205: Code P117 Schematic, Shorted/Open Shift Solenoids "A" & "B" Circuit Courtesy of General MotorsText Corp. G - TESTS W/CODES - 4.6LArticle (p. 250)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 251)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 206: Code P117 Diagnostic Flow Chart - 1 Of 3, Shorted/Open Shift Solenoids "A" & "B" Circuit Courtesy of General Motors Corp.

Fig. 207: Code P117 Diagnostic Flow Chart - 2 Of 3, Shorted/Open Shift Solenoids "A" & "B" Circuit Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 252)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 253)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 208: Code P117 Diagnostic Flow Chart - 3 Of 3, Shorted/Open Shift Solenoids "A" & "B" Circuit Courtesy of General Motors Corp. CODE P119, OPEN/SHORTED FUEL INJECTOR

PCM contains a General Field Effect Transistor Driver (GFD) that control the 8 fuel injector drivers. GFD detects circuit problems with any of the 8 fuel injectors. If any circuit exists, PCM sets trouble code and also sets the second digit of parameter PD17 HI (1) and disables the faulty injector of the engine cycle. Test Conditions Codes P016 and P035 not set. Engine cranked during ignition cycle and fuel pump feedback greater than 10 volts. Failure Conditions Injector circuit fault detected for .5 second. Action Faulty injector disabled for engine run cycle. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks for intermittent. If second digit of PD17 is zero, fault is not present. PCM snapshot should show PD17 second digit as "1". 2) Checks for short to ground on circuit No. 339 or 439. 3) Open may be caused by poor injector harness connector contact. Check terminal contact. 4) Use fuel injector override to pinpoint faulty injector circuit. Disabling one injector would normally create a noticeable difference in engine RPM or idle quality. 5) Checks for open or short to ground in circuit to PCM. 6) Checks injector resistance at engine temperature when the condition occurs. Injector resistance will normally increase with increasing engine temperature. Normal injector resistance should be 825 ohms. 7) Checks if problem is with injector or fuel rail harness. 8) Checks if problem is shorted injector or a short in fuel rail harness. 9) Checks for open or high resistance in fuel injector rail harness or open or high injector resistance.

G - TESTS W/CODES - 4.6LArticle Text (p. 254)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 209: Code P119 Schematic, Open/Shorted Fuel Injector Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 255)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

G - TESTS W/CODES - 4.6LArticle Text (p. 256)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 210: Code P119 Diagnostic Flow Chart - 1 Of 2, Open/Shorted Fuel Injector Courtesy of General Motors Corp.

G - TESTS W/CODES - 4.6LArticle Text (p. 257)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 211: Code P119 Diagnostic Flow Chart - 2 Of 2, Open/Shorted Fuel Injector Courtesy of General Motors Corp. CODE P131, ACTIVE KNOCK SENSOR FAILURE

This test checks the knock sensor's ability to detect a knock. PCM adds an increasing level of spark that should cause detonation and sees if knock sensor detects knock. If knock is not detected, Code P131 will set. Test Conditions MAP value not varying by more than 7.8 kPa (VIN 9) or 10 kPa (VIN Y) at steady state operation. IAT value greater than 30øC and coolant temperature at 40øC or greater. Battery voltage at 11 volts or greater. Engine speed at greater than 1200 RPM for at least 2 seconds. Failure Conditions Spark value of 0.3 degrees (VIN Y) or 3 degrees (VIN 9) will increment until a maximum of 21 degrees is reached. If knock is not detected for one second at maximum spark, Code P131 will set. NOTE:

Test numbers refer to numbers on diagnostic chart. 1) Checks if Code P132 was set due to circuit problem. 2) Checks knock sensor's ability to detect an induced spark.

Fig. 212: Code P131 Schematic, Active Knock Sensor Failure Courtesy of General Motors Corp. G - TESTS W/CODES - 4.6LArticle Text (p. 258)1995 Cadillac Conco

Fig. 213: Code P131 Diagnostic Flow Chart, Active Knock Sensor Failure Courtesy of General Motors Corp. CODE P132, KNOCK SENSOR CIRCUIT FAILURE

This test checks for knock sensor wiring problem. If circuit No. 496 becomes open or shorted, voltage will either increase to greater than 4.2 volts or drop to less than 0.3 volt. If either of these conditions are met for 0.4 second, Code P132 will set. Test Condition Coolant temperature at greater than 104øF (40øC) and battery voltage at 11 volts or greater. Failure Conditions Knock sensor feedback voltage at greater than 4.48 volts 9 (VIN 9) or 4.2 volts (VIN Y), or less than 0.3 volts (VIN Y & 9). Action PCM turns on MIL. NOTE:

Test numbers refer to numbers on diagnostic chart.

1) Checks if Code P035 is also present. A REF LO problem can cause other ignition problems. ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 G - TESTS W/CODES - 4.6LArticle Text (p. 259)1995 Cadillac 2) Checks for proper operating voltage of 0.3-4.2 volts at

PCM terminal 1A13. 3) Checks circuit No. 496 for short to ground. If circuit is okay, sensor is faulty. 4) Checks for short to voltage in circuit No. 496. 5) Checks circuit No. 496 for open.

Fig. 214: Code P132 Schematic, Knock Sensor Circuit Failure Courtesy of General Motors Corp.

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G - TESTS W/CODES - 4.6LArticle Text (p. 261)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 215: Code P132 Diagnostic Flow Chart, Knock Sensor Circuit Failure Courtesy of General Motors Corp. CODE P137, LOSS OF ABS/TCS DATA

This test checks for loss of or invalid ABS/TCS serial data to PCM. When such condition exists for 5 seconds, Code P137 will set. Test Conditions Code P012 not set. Engine speed at 500 RPM or greater for 20 seconds. Failure Condition

Invalid or no serial data from ABS/TCS being received by PCM for 5 seconds. Action PCM sets all serial data from ABS/TCS to zero.

Fig. 216: Code P137 Schematic, Loss Of ABS/TCS Data Courtesy of General Motors Corp. SUMMARY

If no "current" codes are present, and driveability symptoms exist or "history" codes exist, proceed to H - TESTS W/O CODES article in the ENGINE PERFORMANCE section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures. WIRING DIAGRAMS

G - TESTS W/CODES - 4.6LArticle Text (p. 262)1995 Cadillac ConcoursFor Ace M

Fig. 217:

4.6L (VIN Y & 9) PCM Wiring Diagram (1 Of 3)

G - TESTS W/CODES - 4.6LArticle Text (p. 263)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 218: 4.6L (VIN Y & 9) PCM Wiring Diagram (2 Of 3) G - TESTS W/CODES - 4.6LArticle Text (p. 264)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92

Fig. 219: 4.6L (VIN Y & 9) PCM Wiring Diagram (3 Of 3) G - TESTS W/CODES - 4.6LArticle Text (p. 265)1995 Cadillac ConcoursFor Ace Mechanics 123 Main Street San Diego Ca 92 END OF ARTICLE