Automatic Transaxle Diagnosis - 3t40 Chevrolet Cavalier III

APPLICATION

AUTOMATIC TRANSAXLE APPLICATIONS

DESCRIPTION & OPERATION

Powertrain Control Module (PCM) monitors various inputs to control transaxle Torque Converter Clutch (TCC) operation. PCM receives input information from sensors, switches, solenoids and other components. PCM will control TCC apply and release. PCM also includes on-board self-diagnostics. This helps identify which components or circuits may need further testing.

POWERTRAIN CONTROL MODULE

PCM is located forward of right front wheel housing, behind front fascia cavity splash shield. PCM utilizes 2 different colored 80-pin connectors. (Scheme 44) PCM controls ignition, fuel and emission devices related to engine and transaxle upshifts and downshifts.

PCM receives electronic signals from sensors and switches. These signals help PCM determine when to operate various relays and solenoids related to engine and transaxle control.

SENSORS & SWITCHES

PCM controls TCC operation based on coolant temperature, throttle position, transaxle range switch position, vehicle speed sensor and brake pedal switch. System also includes several other switches and sensors which are used for engine control. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

LIMP-IN MODE

If sensor input signals are missing or inadequate for transmission operation, PCM will output preset default values to transmission. This mode maintains vehicle operational and allows it to be driven with reduced transmission function and performance to a repair facility. Malfunction Indicator Light (MIL) will illuminate if malfunction occurs. Vehicle should not be driven for extended periods in limp-in mode.

SELF-DIAGNOSTIC SYSTEM

PCM continuously monitors all electrical circuits. If PCM detects circuit problems or sensors out of range, it will record a Diagnostic Trouble Code (DTC). If problem continues for a predetermined time, MIL will illuminate.

If MIL remains illuminated, DTCs are currently being detected. If MIL is off, but PCM has detected a circuit or sensor problem, DTC(s) are stored in PCM memory.

Stored DTCs may be retrieved from PCM memory using scan tool. DTCs CANNOT be retrieved by grounding 16-pin Data Link Connector (DLC).

Note. Faulty engine sensors and actuators may cause transaxle-related DTCs or driveability problems. Engine faults and related DTCs must be diagnosed and repaired before transaxle-related DTCs are repaired. For additional information on diagnosing and repairing engine-related PCM DTCs, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

TORQUE CONVERTER CLUTCH CONTROL COMPONENTS

The following component signals are used in Torque Converter Clutch (TCC) operation.

Brake Switch

Power from ignition switch passes through brake switch to TCC solenoid. When brake pedal is depressed with TCC engaged, power to TCC solenoid is interrupted, releasing converter clutch and preventing engine from stalling.

Engine Coolant Temperature (ECT) Sensor

This sensor provides PCM with engine coolant temperature information. PCM will not allow TCC operation until signal from this sensor indicates coolant temperature greater than 130-150°F (54-65°C).

TCC Solenoid

Solenoid is energized by PCM to redirect transmission fluid to converter clutch apply valve in auxiliary control valve assembly.

Throttle Position (TP) Sensor

Provides PCM with throttle position information. TCC operation is prevented when throttle position signal is less than a specified value.

Manifold Absolute Pressure (MAP) Sensor

Sensor sends engine vacuum (load) information to PCM.

Vehicle Speed Sensor (VSS)

This sensor sends vehicle speed information to PCM. Vehicle speed must be more than a certain value before TCC can be applied. Speed sensor is mounted on transaxle.

3rd Gear Switch

When open, 3rd gear switch prevents TCC operation. Switch status may be monitored by PCM, or switch may be an integral portion (series circuit) of TCC solenoid power supply.

PCM

To determine application of torque converter clutch, PCM receives and processes information from various input devices. These devices may include vehicle speed sensor, engine coolant temperature, throttle position sensor, 3rd gear switch and brake switch. PCM controls application of torque converter clutch by providing a ground circuit for TCC solenoid.

PRELIMINARY INSPECTION

Prior to diagnosing the transaxle electronic control system, ensure fluid level is correct and throttle and shift cables are properly adjusted. Ensure engine starts with gearshift lever in Park and Neutral to ensure proper adjustment of park/neutral position switch. Ensure all system related fuses are okay. Check wire harnesses for proper routing. Verify all harness and component connections are clean and tight. See WIRING DIAGRAMS . Repair as necessary. If area of fault can not be located or repaired during preliminary inspection, check self-diagnostic system. See DIAGNOSIS & TESTING .

DIAGNOSIS & TESTING

To test electronic control of transaxle TCC solenoid without using self-diagnostics or if self-diagnostics does not function, see TCC SOLENOID under COMPONENT TESTS. After repairs, clear DTCs from PCM memory. See CLEARING DIAGNOSTIC TROUBLE CODES .

If no DTCs are present and vehicle is in limp-in mode, check fused power supply circuit to TCC solenoid. Non-related transaxle component system failures may cause this circuit fuse to fail. ERLS fuse (10-amp) located in instrument panel fuse block supplies power to non-related transaxle components (A/C clutch, cruise control) which may have caused fuse to fail.

DTCs are recorded at various operating times. Some DTCs require operation of affected sensor or switch for 5 seconds; others may require operation for 5 minutes or longer at normal operating temperature, road speed and load. Therefore, some DTCs may not set in a service bay operational mode and may require road testing vehicle in order to duplicate condition under which DTC will set. To retrieve DTCs associated with A/T control, see ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . To retrieve shift lock control-related DTCs, see DIAGNOSTIC SYSTEM CHECK - SHIFT LOCK CONTROL .

ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK

Note. Use of scan tool is required to perform OBD system check. Perform this test prior to performing any diagnostic procedures.

Note. Most problems that occur with MIL or diagnostic system are engine performance or PCM-related. Procedures for repairing these systems and circuits may require additional engine performance repair data. This test contains references to additional procedures not found in this publication.

Introduction

The OBD system check is the starting point for utilizing self-diagnostic system for determining computer-related problems. The OBD system check will determine if MIL is operational, if PCM is functioning properly and is capable of recognizing a fault, and will indicate if any DTCs are stored.

Diagnostic Procedure

1. Connect scan tool to DLC. Turn ignition on, engine off. If scan tool turns on, go to next step. If scan tool does not turn on, see DLC DIAGNOSIS OR NO SCAN TOOL DATA under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
2. With ignition on, observe MIL. If MIL is illuminated, go to next step. If MIL is not illuminated, see MIL INOPERATIVE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
3. Using scan tool, attempt communication with PCM. If communication is established, go to next step. If no communication is established, see DLC DIAGNOSIS OR NO SCAN TOOL DATA under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
4. Using scan tool, save freeze frame and failure record information using "Capture Info" feature. If DTCs are present, identify DTCs and diagnose as necessary. See «DIAGNOSTIC TROUBLE CODE INDEX (A/T CONTROL)»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40) table. If no DTCs are present, diagnose by symptom. See appropriate TROUBLE SHOOTING - NO CODES article in ENGINE PERFORMANCE.

Diagnostic Aids

Do not clear DTCs unless directed by a diagnostic procedure. Clearing DTCs will also clear valuable freeze frame and failure records data. Check for any published technical service bulletins relating to exhibited symptoms or component operation. Check for loose speed sensor mounting or poor sensor connection at PCM. Check for possible bent, backed out, deformed or damaged terminals. Check for weak terminal tension. Check for chafed wire that could short to bare metal or other wiring. Inspect for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value changes.

Note. Only transaxle-related DTCs are listed. For engine-related DTC definitions, see TROUBLE CODE DEFINITIONS article in GENERAL INFORMATION. For engine-related DTC diagnosis, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. These DTCs pertain to engine performance and must be repaired first, as engine performance and related component signals will affect transaxle operation and diagnosis.

DIAGNOSTIC TROUBLE CODE INDEX (A/T CONTROL)

DIAGNOSTIC SYSTEM CHECK - SHIFT LOCK CONTROL

1. Connect scan tool. If scan tool powers up, go to next step. If scan tool does not power up, see SELF-DIAGNOSTIC SYSTEM in BODY CONTROL MODULES - CAVALIER & SUNFIRE article in ACCESSORIES & EQUIPMENT.
2. Turn ignition on, engine off. Attempt to establish communication with Body Control Module (BCM) and PCM. If scan tool communicates with both control modules, go to next step. If scan tool does not communicate with both modules, diagnose communication problem. See SELF-DIAGNOSTIC SYSTEM in BODY CONTROL MODULES - CAVALIER & SUNFIRE article in ACCESSORIES & EQUIPMENT.
3. Using scan tool, retrieve DTCs from BCM and PCM. If scan tool indicates DTCs, go to next step. If scan tool does not indicate DTCs, diagnose by symptom. See SYMPTOM TESTS in appropriate GENERAL MOTORS SHIFT INTERLOCK SYSTEMS article.
4. If scan tool indicates any "U" series (communication) DTCs, diagnose communication problem. See SELF-DIAGNOSTIC SYSTEM in BODY CONTROL MODULES - CAVALIER & SUNFIRE article in ACCESSORIES & EQUIPMENT. If scan tool does not indicate any "U" series DTCs, go to next step.
5. If scan tool indicates DTC B1000 or B1001, diagnose as necessary. See BODY CONTROL MODULES - CAVALIER & SUNFIRE article in ACCESSORIES & EQUIPMENT. If scan tool does not indicate DTC B1000 or B1001, go to next step.
6. If scan tool displays DTC B1328, see «DTC B1328: DEVICE POWER CIRCUIT HIGH»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40) under DIAGNOSTIC TESTS. If scan tool does not display DTC B1328, diagnose indicated DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE INDEX (SHIFT LOCK CONTROL)»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40) table. If indicated DTCs are not included within this article, see appropriate article related to DTC for diagnostics (i.e., ACCESSORIES & EQUIPMENT, ENGINE PERFORMANCE, etc.).

DIAGNOSTIC TROUBLE CODE INDEX (SHIFT LOCK CONTROL)

CLEARING DIAGNOSTIC TROUBLE CODES

DTCs can be cleared using scan tool. If scan tool is not available, turn ignition switch to OFF position. Remove PCM/IGN fuse (10-amp) from fuse block for 30 seconds. Replace fuse. If fuse cannot be located, disconnect PCM pigtail at battery for 30 seconds. DTCs may also be cleared by disconnecting negative battery cable. However, this may result in loss of other on-board memory data, such as preset radio tuning. After power to PCM is removed, poor driveability may occur until control module "relearns" operating parameters.

DTCs will also be cleared under the following conditions: PCM will turn off MIL after 3 consecutive ignition cycles without a failure reported. PCM will cancel DTC default actions when fault no longer exists and ignition is cycled off long enough to power down PCM. DTC is cleared when vehicle has achieved 40 warm-up cycles without failure reported.

HARD OR INTERMITTENT DTC DETERMINATION

During any diagnostic procedure, it must be determined if DTCs are hard failure or intermittent failure. Diagnostic tests will not usually help analyze intermittent failures. To determine hard and intermittent DTCs, proceed as follows

1. Enter diagnostic mode. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40__on-board-diagnostic-obd-system-check) . Read and record all stored DTCs. Exit diagnostic mode and clear DTCs. See «CLEARING DIAGNOSTIC TROUBLE CODES»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40__clearing-diagnostic-trouble-codes) .
2. Apply parking brake and place transaxle in Neutral or Park. Block drive wheels and start engine. MIL should turn off. Run warm engine at curb idle for 2 minutes and note MIL.
3. If MIL illuminates, enter diagnostic mode. Read and record DTCs. This will reveal hard failure DTCs. DTCs may require a road test to reset hard failure after clearing DTCs. If MIL does not illuminate, all stored DTCs were intermittent failures.

CONNECTOR IDENTIFICATION

Note. For connector identification, refer to illustrations. (Scheme 44)- (Scheme 53).

Scheme 44

Scheme 45

Scheme 46

Scheme 47

Scheme 48

Scheme 49

Scheme 50

Scheme 51

Scheme 52

Scheme 53

SUMMARY

If no hard DTCs are present, and driveability symptoms or intermittent DTCs exist, diagnose system by verifying electronic control system circuit operation. This may be accomplished by using scan tool to compare actual circuit data values to typical manufacturer specified data values. Refer to scan tool manufacturer's instruction manual.

The following diagnostic tests are DTC specific. Always perform OBD system check prior to performing any diagnostic procedure. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under DIAGNOSIS & TESTING. For circuit, terminal and wire color identification, see WIRING DIAGRAMS . For transaxle-related connector identification, see CONNECTOR IDENTIFICATION under DIAGNOSIS & TESTING.

Diagnostic aids located at end of each diagnostic test are additional tips used to help diagnose DTCs when diagnostic procedures do not locate area of fault.

Circuit Description

The BCM monitors battery voltage. If battery voltage is greater than specified range, BCM sets DTC B1328 and turns off certain outputs to prevent damage to internal circuitry.

Conditions for Running DTC B1328

DTC will run under the following conditions

1. Ignition switch must be in ON position.

Conditions for Setting DTC B1328

DTC will set under the following conditions

1. DTC will set when if system voltage is greater than 18.5 volts for 5 seconds.

Action Taken By BCM

BCM performs the following actions if DTC is set

1. Disables courtesy light output.
2. Disables instrument cluster dimming light output.
3. Disables SECURITY indicator light output.

1. Check operating condition of charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. Repair as necessary. Go to next step.
2. Connect scan tool. Turn ignition on, engine off. Using scan tool, monitor DTC information for DTC B1328. If DTC is current, go to step 4 . If DTC is not current, go to next step.
3. Most occurrences of DTC B1328 are caused by jump-starting vehicle. Review operating conditions of vehicle with vehicle owner. If jump-starting vehicle is cause of DTC, verify proper operation of charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. If jump-starting vehicle is not cause of DTC, go to next step.
4. Using scan tool, clear DTCs. Operate vehicle under conditions required to set DTC. If DTC returns, go to next step. If DTC does not return, system is okay.
5. Check charging system. See CHARGING SYSTEM TEST under ON-VEHICLE TESTING in appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. Repair as necessary. If no problem is found, go to next step.
6. Replace BCM. After replacement, perform setup procedure for BCM. See PROGRAMMING in appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS.

The BCM controls A/T shift lock control solenoid. Positive voltage is supplied through ERLS fuse (10-amp) through circuit 439 to terminal "B" of A/T shift lock control solenoid. The BCM supplies a ground signal to solenoid through circuit 323 to terminal "A" of solenoid. When brake pedal is depressed, the BCM removes the ground signal allowing solenoid to disengage. This action allows vehicle to be shifted out of Park.

Conditions for Running DTC B2707

DTC will run under the following conditions

1. Ignition switch in ON position.
2. Brake pedal depressed.

Conditions for Setting DTC B2707

DTC will set under the following conditions

1. Shift lock control circuit is open or shorted to ground for 5 seconds.

Action Taken When DTC Sets

The following actions occur if DTC is set

1. If shift lock control circuit is open, A/T shift lock solenoid is inoperative.
2. If shift lock control circuit is shorted to ground, A/T shift lock solenoid will be stuck in the engaged position.

1. Check body control system. See BODY CONTROL SYSTEM DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in BODY CONTROL MODULES - CAVALIER & SUNFIRE article in ACCESSORIES & EQUIPMENT. After checking body control system, go to next step.
2. Turn ignition on, engine off. Using scan tool, command A/T shift lock solenoid on and off. If solenoid turns on and off with each command, check for intermittent condition. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40) . If solenoid does not turn on and off with each command, go to next step.
3. Turn ignition off. Disconnect A/T shift lock solenoid harness connector. Turn ignition on, engine off. Using test light connected to ground, probe solenoid ignition feed circuit at harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
4. Connect test light between solenoid ignition feed and control circuits at harness connector. Using scan tool, command A/T shift lock solenoid on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
5. If test light remains illuminated with each command, go to step 7 . If test light does not remain illuminated with each command, go to next step.
6. Check for open in A/T shift lock solenoid control circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
7. Check for short to ground in A/T shift lock solenoid control circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
8. Check for poor connections at A/T shift lock solenoid. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
9. Check for poor connections at BCM. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
10. Repair A/T shift lock solenoid ignition feed circuit. After repairs, go to step 13 .
11. Replace A/T shift lock solenoid. After repairs, go to step 13 .
12. Replace BCM. After replacement, perform setup procedure for BCM. See PROGRAMMING in appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. After repairs, go to next step.
13. Using scan tool, clear DTCs. Operate vehicle under conditions required to set DTC. If DTC returns, return to step 2 . If DTC does not return, system is okay.

If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value changes.

The BCM controls A/T shift lock control solenoid. Positive voltage is supplied through ERLS fuse (10-amp) through circuit 439 to terminal "B" of A/T shift lock control solenoid. The BCM supplies a ground signal to solenoid through circuit 323 to terminal "A" of solenoid. When brake pedal is depressed, the BCM removes ground signal allowing the solenoid to disengage. This action allows the vehicle to be shifted out of Park.

Conditions for Running DTC B2708

DTC will run under the following conditions

1. Ignition switch in ON position.
2. Brake pedal depressed.

Conditions for Setting DTC B2708

DTC will set under the following conditions

1. Shift lock control circuit is shorted to battery voltage for one second.

The following actions occur if DTC is set

1. BCM disables A/T shift lock control output for remainder of ignition cycle.

1. Check body control system. See BODY CONTROL SYSTEM DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in BODY CONTROL MODULES - CAVALIER & SUNFIRE article in ACCESSORIES & EQUIPMENT. After checking body control system, go to next step.
2. Turn ignition on, engine off. Using scan tool, command A/T shift lock solenoid on and off. If solenoid turns on and off with each command, check for intermittent condition. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40) . If solenoid does not turn on and off with each command, go to next step.
3. Turn ignition off. Disconnect A/T shift lock solenoid harness connector. Turn ignition on, engine off. Using test light connected to ground, probe solenoid ignition feed circuit at harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
4. Connect test light between solenoid ignition feed and control circuits at harness connector. Using scan tool, command A/T shift lock solenoid on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
5. If test light remains illuminated with each command, go to step 7 . If test light does not remain illuminated with each command, go to next step.
6. Check for short to voltage in A/T shift lock solenoid control circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
7. Check for short to ground in A/T shift lock solenoid control circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
8. Check for poor connections at A/T shift lock solenoid. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
9. Check for poor connections at BCM. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
10. Repair A/T shift lock solenoid ignition feed circuit. After repairs, go to step 13 .
11. Replace A/T shift lock solenoid. After repairs, go to step 13 .
12. Replace BCM. After replacement, perform setup procedure for BCM. See PROGRAMMING in appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. After repairs, go to next step.
13. Using scan tool, clear DTCs. Operate vehicle under conditions required to set DTC. If DTC returns, return to step 2 . If DTC does not return, system is okay.

If shift lock control circuit is shorted to battery voltage, A/T shift lock solenoid will be inoperative. The vehicle will shift out of Park without depressing brake pedal. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value changes.

Vehicle speed is signaled to PCM by Vehicle Speed Sensor (VSS). Sensor is a Permanent Magnet (PM) generator mounted to transaxle case. PM generator produces AC voltage as speed sensor rotor teeth pass sensor's magnetic field. AC voltage level increases as speed of vehicle increases. PCM converts AC voltage into a digital signal. PCM uses this signal to calculate vehicle speed and when to apply TCC. DTC P0502 is set when PCM detects a low vehicle output speed when vehicle has high engine speed in drive range.

Conditions For Running DTC P0502

DTC will run under the following conditions

1. Transaxle is in Drive.
2. No MAP sensor DTCs P0106, P0107 or P0108.
3. No TP sensor DTCs P0122 or P0123.
4. TP sensor angle is greater than 15 percent.
5. Engine speed is 2000-4800 RPM.
6. MAP sensor value is greater than 7.5 psi (50 kPa).
7. Transaxle is in a drive range.

Conditions For Setting DTC P0502

DTC will set under the following conditions

1. Vehicle is under all conditions required to run DTC.
2. Vehicle speed is less than 2 MPH for 3 seconds.

Action Taken By PCM

PCM performs the following actions if DTC is set

1. Illuminates MIL.
2. Inhibits TCC engagement.
3. PCM stores operating condition information as freeze frame and failure records, and DTC P0502 is stored in PCM history if conditions occur for a second consecutive trip.

1. Perform OBD system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40__on-board-diagnostic-obd-system-check) under DIAGNOSIS & TESTING. After performing OBD system check, go to next step.
2. Turn ignition on, engine off. Using scan tool, record freeze frame and failure records for reference, and then clear DTCs. Raise and support vehicle. Start engine and let idle. Place gearshift lever in "D" position. With drive wheels rotating, monitor transaxle output speed with scan tool. If transaxle output speed does not increase when wheel speed increases, go to next step. If transaxle output speed increases when wheel speed increases, condition is intermittent. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40) .
3. Turn engine off. Disconnect both PCM 80-pin harness connectors. PCM is located forward of right front wheel housing, behind front fascia cavity splash shield. With DVOM set to AC volt scale, connect leads between PCM connector C1, terminal No. 64 and connector C2, terminal No. 61. Turn ignition on. Rotate front drive wheel by hand and observe DVOM. If voltage is greater than .5 volt AC, go to step 14 . If voltage is not greater than .5 volt AC, go to next step.
4. Leave DVOM leads connected. Measure circuit resistance. If resistance is 139-376 ohms, go to step 8 . If resistance is not 139-376 ohms, go to next step.
5. If circuit resistance is greater than 376 ohms, go to step 11 . If circuit resistance is not greater than 376 ohms, go to next step.
6. Leave DVOM leads connected. Disconnect VSS harness connector at transaxle. If resistance is less than 139 ohms, go to next step. If resistance is not less than 139 ohms, go to step 13 .
7. Check condition of VSS signal and ground circuits. Repair as necessary. After repairs, go to step 15 .
8. Check condition of VSS signal circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to next step.
9. Reconnect PCM harness connectors. Turn ignition on. Using DVOM set to DC volt scale, measure voltage between VSS harness connector terminals. If voltage is indicated, go to next step. If voltage is not indicated, go to step 12 .
10. Check VSS signal circuit for short to voltage. Repair as necessary. After repairs, go to step 15 .
11. Check VSS signal and ground circuits for open. Repair as necessary. After repairs, go to step 15 . If circuits are okay, go to step 13 .
12. Remove VSS assembly. Check for incorrect VSS application, damage, excessive sensor-to-rotor gap, incorrect alignment or sensor rotor damage. Repair as necessary. After repairs, go to step 15 .
13. Replace VSS assembly. After repairs, go to step 15 .
14. Replace PCM. After replacement, PCM must be reprogrammed. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. After repairs, go to next step.
15. Reconnect all components. Using scan tool, clear DTCs. Operate vehicle under conditions required to run DTC. See «CONDITIONS FOR RUNNING DTC P0502»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40__conditions-for-running-dtc-p0502) . If DTC does not return, system is okay. If DTC returns, return to step 1 .

Check for damaged speed sensor or rotor teeth. Check for Electromagnetic Interferences (EMI) induced on Purple and Yellow wires by misrouted wiring harness. Check for loose speed sensor mounting or poor connection at PCM. Check for bent, backed out, deformed or damaged terminals. Check for weak terminal tension. Check for chafed wires that could short to bare metal or other wiring. Inspect for broken wires inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

Vehicle speed is signaled to PCM by Vehicle Speed Sensor (VSS). Sensor is a Permanent Magnet (PM) generator mounted to transaxle case. PM generator produces an AC voltage as speed sensor rotor teeth pass sensor's magnetic field. AC voltage level increases as speed of vehicle increases. PCM converts AC voltage into digital signal. PCM uses this signal to calculate vehicle speed and when to apply TCC. DTC P0503 is set when PCM detects a low vehicle output speed when vehicle has high engine speed in drive gear.

Conditions For Running DTC P0503

DTC will run under the following conditions

1. Engine is running.
2. More than 6 seconds since last gear change.
3. Transaxle output speed is greater than 500 RPM for 5 seconds.

Conditions For Setting DTC P0503

DTC will set under the following conditions

1. Transaxle output speed drops more than 1200 RPM in a drive range for more than 4 seconds.

PCM performs the following actions if DTC is set

1. Illuminates MIL when fault is set.
2. Inhibits TCC engagement.
3. DTC P0503 is stored in PCM history.

1. Perform OBD system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40__on-board-diagnostic-obd-system-check) under DIAGNOSIS & TESTING. After performing OBD system check, go to next step.
2. Turn ignition on, engine off. Using scan tool, record freeze frame and failure records for reference, and then clear DTCs. Raise and support vehicle. Start engine and let idle. Place gearshift lever in "D" position. With drive wheels rotating, monitor transaxle output speed with scan tool. If transaxle output speed does not increase when wheel speed increases, go to next step. If transaxle output speed increases when wheel speed increases, condition is intermittent. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40) .
3. Turn engine off. Disconnect both PCM 80-pin harness connectors. PCM is located forward of right front wheel housing, behind front fascia cavity splash shield. With DVOM set to AC volt scale, connect leads between PCM connector C1, terminal No. 64 and connector C2, terminal No. 61. Turn ignition on. Rotate front drive wheel by hand and observe DVOM. If voltage is greater than .5 volt AC, go to step 14 . If voltage is not greater than .5 volt AC, go to next step.
4. Leave DVOM leads connected. Measure circuit resistance. If resistance is 139-376 ohms, go to step 8 . If resistance is not 139-376 ohms, go to next step.
5. If circuit resistance is greater than 376 ohms, go to step 11 . If circuit resistance is not greater than 376 ohms, go to next step.
6. Leave DVOM leads connected. Disconnect VSS harness connector at transaxle. If resistance is less than 139 ohms, go to next step. If resistance is not less than 139 ohms, go to step 13 .
7. Check condition of VSS signal and ground circuits. Repair as necessary. After repairs, go to step 15 .
8. Check condition of VSS signal circuit. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to next step.
9. Reconnect PCM harness connectors. Turn ignition on. Using DVOM set to DC volt scale, measure voltage between VSS harness connector terminals. If voltage is indicated, go to next step. If voltage is not indicated, go to step 12 .
10. Check VSS signal circuit for short to voltage. Repair as necessary. After repairs, go to step 15 .
11. Check VSS signal and ground circuits for open. Repair as necessary. After repairs, go to step 15 . If circuits are okay, go to step 13 .
12. Remove VSS assembly. Check for incorrect VSS application, damage, excessive sensor-to-rotor gap, incorrect alignment or sensor rotor damage. Repair as necessary. After repairs, go to step 15 .
13. Replace VSS assembly. After repairs, go to step 15 .
14. Replace PCM. After replacement, PCM must be reprogrammed. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. After repairs, go to next step.
15. Reconnect all components. Using scan tool, clear DTCs. Operate vehicle under conditions required to run DTC. See CONDITIONS FOR RUNNING DTC P0503. If DTC does not return, system is okay. If DTC returns, return to step 1 .

Check for damaged speed sensor or rotor teeth. Check for Electromagnetic Interferences (EMI) induced on VSS signal and ground circuits by misrouted wiring harness. Check for loose speed sensor mounting or poor sensor connection at PCM. Check for bent, backed out, deformed or damaged terminals. Check for weak terminal tension. Check for chafed wires that could short to bare metal or other wiring. Inspect for broken wires inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value changes.

Brake switch is used to indicate brake pedal status to PCM. Normally-closed brake switch supplies battery voltage on brake switch input signal circuit (Purple wire) to PCM. When brake pedal is applied, brake switch opens, interrupting voltage to PCM. When brake pedal is released, voltage is constant to PCM. When PCM detects zero volts at brake switch input, PCM de-energizes TCC solenoid. DTC P0719 is set when PCM detects an open (stuck on) brake switch during acceleration.

Conditions For Running DTC P0719

DTC will run under the following conditions

1. Ignition switch is in ON position.

Conditions For Setting DTC P0719

DTC will set if PCM detects open in brake switch circuit for 15 minutes and the following conditions occur 8 consecutive times

1. Vehicle speed is less than 5 MPH.
2. Then vehicle speed is 5-20 MPH for 3 seconds.
3. Then vehicle speed is greater than 20 MPH for 6 seconds.

PCM performs the following actions if DTC is set

1. Will not illuminate MIL when fault is set.
2. PCM stores operating condition information as freeze frame and failure records, and DTC P0719 is stored in PCM history.

1. Perform OBD system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40__on-board-diagnostic-obd-system-check) under DIAGNOSIS & TESTING. After performing OBD system check, go to next step.
2. Turn ignition on, engine off. Using scan tool, record failure records for reference, and then clear DTCs. Select brake switch parameter on scan tool. Disconnect brake switch connector. Connect fused jumper wire between brake switch connector terminals. If brake switch status on scan tool changes from OPEN to CLOSED, go to step 5 . If brake switch status on scan tool does not change from OPEN to CLOSED, go to next step.
3. Remove and inspect ERLS fuse (10-amp) located in fuse block. If fuse is open, go to next step. If fuse is okay, go to step 6 .
4. Check ignition feed circuit to brake switch for short to ground. Repair as necessary. After repairs, go to step 9 .
5. Check brake switch for proper adjustment. Adjust as necessary. After adjustment, go to step 9 . If adjustment is okay, go to step 7 .
6. Check for open in brake switch input circuit between brake switch and PCM. Repair as necessary. After repairs, go to step 9 . If circuit is okay, go to step 8 .
7. Replace brake switch. After repairs, go to step 9 .
8. Replace PCM. After replacement, PCM must be reprogrammed. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. After repairs, go to next step.
9. Using scan tool, clear DTCs. Turn ignition on, engine off. Wait for 3 seconds, and then apply and release brake pedal (PCM must receive 12 volts for 3 seconds). Using scan tool, check for DTCs. If DTC does not return, system is okay. If DTC returns, return to step 1 .

If PCM detects a brake switch fault, brake switch input is disregarded for TCC scheduling. PCM then uses throttle position and vehicle speed input to determine TCC apply and release. Use of these inputs may result in noticeable harsh apply or abrupt release of TCC. Check brake switch for correct adjustment. Inspect wiring for poor connections at PCM and at brake switch connector. Check for bent, backed out, deformed or damaged terminals. Check for weak terminal tension. Check for chafed wires that could short to bare metal or other wiring. Inspect for broken wires inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value changes.

Brake switch is used to indicate brake pedal status to PCM. Normally-closed brake switch supplies battery voltage on brake switch input signal circuit (Purple wire) to PCM. When brake pedal is applied, brake switch opens, interrupting voltage to PCM. When brake pedal is released, voltage is constant to PCM. When PCM detects zero volts at brake switch input, PCM de-energizes TCC solenoid. DTC P0724 is set when PCM detects a closed (stuck off) brake switch during deceleration.

Conditions For Running DTC P0724

DTC will run under the following conditions

1. Ignition switch is in ON position.

Conditions For Setting DTC P0724

DTC will set if PCM detects closed brake switch circuit during deceleration and the following conditions occur 8 consecutive times

1. Vehicle speed is greater than 20 MPH for 6 seconds.
2. Then vehicle speed is 5-20 MPH for 3 seconds.
3. Then vehicle speed remains less than 5 MPH.

PCM performs the following actions if DTC is set

1. Will not illuminate MIL when fault is set.
2. PCM stores operating condition information as freeze frame and failure records, and DTC P0724 is stored in PCM history.

1. Perform OBD system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40__on-board-diagnostic-obd-system-check) under DIAGNOSIS & TESTING. After performing OBD system check, go to next step.
2. Turn ignition on, engine off. Using scan tool, record failure records for reference, and then clear DTCs. Select brake switch parameter on scan tool. Disconnect brake switch connector. If brake switch status on scan tool changes from CLOSED to OPEN, go to step 4 . If brake switch status on scan tool does not change from CLOSED to OPEN, go to next step.
3. Check for short to voltage in brake switch input circuit between brake switch and PCM. Repair as necessary. After repairs, go to step 6 . If circuit is okay, go to step 5 .
4. Replace brake switch. After repairs, go to step 6 .
5. Replace PCM. After replacement, PCM must be reprogrammed. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. After repairs, go to next step.
6. Using scan tool, clear DTCs. Turn ignition on, engine off. Apply brake pedal for 3 seconds. Using scan tool, check for DTCs. If DTC does not return, system is okay. If DTC returns, return to step 1 .

Check brake switch for proper adjustment. Inspect wiring for poor connections at PCM and at brake switch connector. Check for bent, backed out, deformed or damaged terminals. Check for weak terminal tension. Check for chafed wires that could short to bare metal or other wiring. Inspect for broken wires inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value changes.

Power is supplied to Torque Converter Clutch (TCC) solenoid from fuse panel through TCC solenoid valve ignition feed circuit (Pink wire). From solenoid, ground path is interrupted by normally-open 3rd clutch pressure switch. PCM controls activation of solenoid by grounding circuit through internal switch in PCM. Although PCM may command TCC on, TCC will not apply until 3rd clutch fluid (3rd clutch engaged) closes pressure switch to complete circuit. When PCM determines conditions are correct, circuit is grounded through PCM, activating solenoid. When solenoid is on, exhaust fluid is blocked, which moves TCC control valve to applied position. This provides fluid pressure to engage TCC. DTC P0742 is set when PCM detects low TCC slip speed when TCC is commanded off.

Conditions For Running DTC P0742

DTC will run under the following conditions

1. No TP sensor DTCs P0121, P0122 or P0123.
2. TCC is commanded off.
3. Engine speed is 1500-4000 RPM.
4. Engine torque is greater than 10 ft. lbs (13 N.m).
5. More than 6 seconds since last gear change.
6. Speed ratio is 0.9-1.375.
7. Throttle angle is greater than 8 percent.
8. Slip speed is -20 to 20 RPM for 10 seconds.
9. Vehicle speed is 35-75 MPH.

Conditions For Setting DTC P0742

DTC will set under the following conditions

1. PCM detects 2 or more instances of TCC being stuck on.

PCM performs the following actions if DTC is set

1. Illuminates MIL after 2 ignition cycles with failure present.
2. DTC P0742 is stored in PCM history.

1. Perform OBD system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40__on-board-diagnostic-obd-system-check) under DIAGNOSIS & TESTING. After performing OBD system check, go to next step.
2. Turn ignition on, engine off. Using scan tool, record freeze frame and failure records for reference, and then clear DTCs. Turn ignition off. Disconnect transaxle wiring harness connector. Drive vehicle in "D3" position at a steady throttle position angle greater than 8 percent to 40 MPH or more. With scan tool in snap shot mode, record TCC slip speed when transaxle is in 3rd gear with TCC engaged. If TCC slip speed is not -20 to 20 RPM, go to next step. If TCC slip speed is -20 to 20 RPM, go to step 9.
3. Turn ignition off. Connect test light between terminals "A" and "D" at engine side of transaxle in-line harness connector. (Scheme 51) Turn ignition on. If test light illuminates, go to next step. If test light does not illuminate, go to step 6.
4. Check for short to ground in TCC solenoid control circuit between transaxle in-line harness connector and PCM. Repair as necessary. After repairs, go to step 13. If circuit is okay, go to next step.
5. Replace PCM. After replacement, PCM must be reprogrammed. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. After repairs, go to step 13.
6. Remove transaxle valve body cover. Disconnect Black wire from 3rd clutch pressure switch. Connect DVOM leads between terminal "A" of transaxle in-line harness connector to Black wire at TCC solenoid valve. If resistance is 19-31 ohms, go to step 10. If resistance is not 19-31 ohms, go to next step.
7. Check for short to ground in circuit between 3rd clutch pressure switch and terminal "A" of transaxle in-line harness connector. Repair as necessary. After repairs, go to next step. If circuit is okay, go to step 9.
8. Replace TCC solenoid valve. After repairs, go to step 13.
9. TCC release oil circuit is blocked. Check for plugged or restricted oil cooler lines or oil cooler. See TRANSAXLE & OIL COOLER FLOW CHECK under ON-VEHICLE SERVICE in HYDRA-MATIC 3T40 OVERHAUL article. Repair as necessary. After repairs, go to step 13. If oil cooler and cooler lines are okay, go to next step.
10. TCC solenoid valve may be stuck closed. Check valve for sediment or mechanical failure. Replace if necessary. After repairs, go to step 13. If valve is okay, go to next step.
11. Converter clutch control valve may be stuck on. Check valve for sediment, binding or mechanical failure. Repair as necessary. After repairs, go to step 13. If valve is okay, go to next step.
12. Check torque converter clutch. If clutch is mechanically applied (stuck on), replace torque converter. After repairs, go to next step.
13. Using scan tool, clear DTCs. Drive vehicle in "D3" position with throttle position angle constant at 30 percent. TCC slip speed must be greater than 120 RPM for 5 seconds. Using scan tool, check for DTCs. If DTC does not return, system is okay. If DTC returns, return to step 1.

If vehicle stalls repeatedly, TCC is stuck on. Inspect wiring for poor connections at PCM and transaxle wiring harness connector. Check for bent, backed out, deformed or damaged terminals. Check for weak terminal tension. Check for chafed wires that could short to bare metal or other wiring. Inspect for broken wires inside insulation.

PCM monitors Torque Converter Clutch (TCC) slip speed by calculating difference between engine speed and transaxle output speed. While driving with transaxle in "D3" position and TCC engaged, engine speed should closely match transaxle output speed. DTC P1870 is set when PCM detects excessive TCC slip of TCC, forward clutch and direct clutch when TCC is engaged in 3rd gear.

Conditions For Running DTC P1870

DTC will run under the following conditions

1. No TP sensor DTCs P0121, P0122 and P0123.
2. No vehicle speed sensor DTCs P0502 and P0503.
3. Engine speed is 1500-3600 RPM.
4. Engine torque is greater than 20 ft. lbs. (27 N.m).
5. Throttle position angle is 10-40 percent.
6. TCC is on for 5 seconds.
7. TCC slip speed is greater than 140 RPM for 8 seconds.
8. Vehicle speed is 35-75 MPH.
9. Speed ratio is 0.9-1.375.

Conditions For Setting DTC P1870

DTC will set under the following conditions

1. PCM transaxle slip counter is greater or equal to one count.

PCM performs the following actions if DTC is set

1. Illuminates MIL when fault is set.
2. Inhibits TCC engagement.
3. DTC P1870 is stored in PCM history.

1. Perform OBD system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40__on-board-diagnostic-obd-system-check) under DIAGNOSIS & TESTING. After performing OBD system check, go to next step.
2. Turn ignition on, engine off. Using scan tool, record freeze frame and failure records for reference, and then clear DTCs. Drive vehicle in "D3" position with TCC engaged. Using scan tool in snap shot mode, record TCC slip speed when transaxle is in 3rd gear with TCC engaged. While TCC is engaged, TCC slip speed should be greater than 150 RPM. If RPM is as specified, go to next step. If RPM is not as specified, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/automatic-trans/#automatic-transaxle-diagnosis-3t40).
3. Turn ignition off. Disconnect transaxle in-line harness connector. Turn ignition on. Using test light connected to ground, probe terminal "A" at engine side of transaxle in-line harness connector. (Scheme 51) If test light illuminates, go to next step. If test light does not illuminate, go to step 5.
4. Using test light connected to battery voltage, probe terminal "D" at engine side of transaxle in-line harness connector. (Scheme 51) Using scan tool, command TCC solenoid on and off several times. If test light toggles on and off as TCC solenoid is commanded, go to step 8. If operation is not as specified, go to step 6.
5. Check for open in TCC solenoid valve ignition feed circuit between TCC solenoid valve and fuse block. Repair as necessary. After repairs, go to step 7.
6. Check for open in TCC solenoid valve control circuit between transaxle in-line harness connector and PCM. Repair as necessary. After repairs, go to step 17. If circuit is okay, go to next step.
7. Replace PCM. After replacement, PCM must be reprogrammed. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. After repairs, go to step 17.
8. Check transaxle fluid level and condition. Add or replace if necessary, and then go to next step.
9. Check transaxle selector lever for incorrect adjustment. Check transaxle gearshift lever cable for binding. Adjust or repair as necessary. After repairs, go to step 17. If no problem is found, go to next step.
10. Check T.V. cable for incorrect adjustment, binding or breakage. Adjust or repair as necessary. After repairs, go to step 17. If no problem is found, go to next step.
11. Check for low line pressure. See HYDRAULIC PRESSURE TESTS under PERFORMANCE TESTS in HYDRA-MATIC 3T40 OVERHAUL article. If pressure is within specifications, go to step 13. If pressure is not within specifications, go to next step.
12. Check for internal transaxle conditions which may contribute to low line pressure. Repair as necessary. After repairs, go to step 17.
13. Check TCC hydraulic circuit for loose TCC solenoid valve, damaged solenoid valve "O" ring seal, TCC solenoid valve check ball not seating, contaminates in TCC solenoid or fluid circuit, or converter clutch control valve stuck in OFF position. Repair as necessary. After repairs, go to step 17. If no problem is found, go to next step.
14. Check for damaged torque converter or worn/damaged torque converter turbine shaft seal. Repair as necessary. After repairs, go to step 17. If no problem is found, go to next step.
15. Check direct clutch for missing No. 5 check ball, rolled/cut driven sprocket support seals, burned clutch plates, or damaged/worn piston seals. Repair as necessary. After repairs, go to step 17. If no problem is found, go to next step.
16. Check forward clutch for restricted spacer plate orifice, burned clutch plates, or damaged/worn piston seals. Repair as necessary. After repairs, go to next step.
17. Using scan tool, clear DTCs. Drive vehicle in "D3" position with throttle position angle at 10-50 percent, vehicle speed at 40-55 MPH and with TCC commanded on by PCM. TCC slip speed must be -20 to 40 RPM for 3 seconds. Using scan tool, check for DTCs. If DTC does not return, system is okay. If DTC returns, return to step 1.

Inspect wiring for poor connections at PCM and at transaxle wiring harness connector. Check for bent, backed out, deformed or damaged terminals. Check for weak terminal tension. Check for chafed wires that could short to bare metal or other wiring. Inspect for broken wires inside insulation. Verify final drive ratio is correct for specific vehicle. Check for vehicle overloading or trailer towing beyond vehicle capacity (if applicable).

Note. When diagnosing converter clutch problems, ensure engine and vacuum systems are operating properly. Some solenoids have an internal pressure switch in series with solenoid winding and will not indicate continuity until that pressure switch is applied by transaxle hydraulic pressure.

Disconnect harness connector to Torque Converter Clutch (TCC) solenoid. Measure resistance between TCC solenoid terminals "A" and "X". (Scheme 53) Resistance should be 19-31 ohms. If resistance is not as specified, replace TCC solenoid.

3RD CLUTCH PRESSURE SWITCH

Disconnect 3rd clutch pressure switch connector. Measure resistance between switch terminals, and then between each switch terminal and transaxle case. Resistance should be greater than 250 k/ohms for each measurement. Replace switch if resistance is not as specified.

Removal & Installation

Disconnect negative battery cable. Raise and support vehicle. Remove right front fascia cavity splash shield. Disconnect horn electrical connector. Remove horn. Disconnect PCM connectors. Remove retaining bolts. Slide PCM and retainer from bracket. Remove retainer from PCM. To install, reverse removal procedure. Tighten retaining bolts to 89 INCH lbs. (10 N.m).

Transaxle Electronic Control System Wiring Diagram (Cavalier & Sunfire - 2.2L). Scheme 54

See also:
• WIRING DIAGRAMS
• DIAGNOSIS & TESTING
• CLEARING DIAGNOSTIC TROUBLE CODES
• ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK
• DIAGNOSTIC SYSTEM CHECK - SHIFT LOCK CONTROL
• CONNECTOR IDENTIFICATION
• CONDITIONS FOR RUNNING DTC P0502