Automatic Transaxle Diagnosis - 4T40-E & 4T45-E: Other Pontiac Sunfire I

TRANSAXLE COMPONENTS & SYSTEMS

Note. For transaxle electronic component locations (Scheme 130)

The mechanical components of this unit are as follows

1. A torque converter with a Torque Converter Clutch (TCC).
2. A drive link assembly.
3. Intermediate-4th and low-reverse friction band assemblies.
4. Forward, coast, 2nd, reverse, and direct multiple disc clutch assemblies.
5. Two planetary gear sets: input and reaction.
6. Two roller clutches: low and 2nd.
7. One sprag clutch.
8. One vane type oil pump.
9. One control valve assembly.
10. A final drive and differential assembly.

The electrical components of this unit are as follows

1. Two shift solenoid valves: 1-2 and 2-3.
2. A Torque Converter Clutch Pulse Width Modulated (TCC PWM) solenoid valve.
3. A Pressure Control (PC) solenoid valve.
4. A Transmission Fluid Temperature (TFT) sensor.
5. Two speed sensors: input and output speed sensor.
6. A Transmission Fluid Pressure (TFP) manual valve position switch assembly.
7. A transaxle internal wiring harness assembly.
8. A Park/Neutral Position (PNP) switch.

Scheme 130

Pressure Control Solenoid Valve

The Pressure Control (PC) solenoid valve is a precision electronic pressure regulator that controls the line pressure. This control is based on the flow of current through the coil windings of the valve. As the flow of current is increased, the magnetic field which is produced by the coil moves the solenoid's plunger further away from the exhaust port. Opening the exhaust port decreases the output fluid pressure regulated by the PC solenoid valve, which ultimately decreases line pressure.

The PCM controls the PC solenoid valve based on various inputs, including throttle position, fluid temperature, MAP sensor, and gear state.

The PCM controls the PC solenoid valve on a positive duty cycle at a fixed frequency of 614 Hz. Duty cycle is defined as the percent of time current is flowing through the solenoid coil during each cycle. A higher duty cycle provides a greater current flow through the solenoid. The high, positive, side of the PC solenoid valve electrical circuit at the PCM controls the PC solenoid valve operation. The PCM provides a ground path for the circuit, monitors average current and continuously varies the PC solenoid valve duty cycle to maintain the correct average current flowing through the PC solenoid valve. See PC SOLENOID VALVE DUTY CYCLE table.

PC SOLENOID VALVE DUTY CYCLE

1-2 & 2-3 Shift Solenoid Valves

The shift solenoid valves are two identical, electronic exhaust valves that control upshifts and downshifts in all forward gear ranges. These valves are normally open. The shift solenoid valves work together in a combination of on and off sequences to control the positions of the 1-2, 2-3, and 3-4 shift valve trains. The PCM monitors numerous inputs to determine the appropriate solenoid state combination and transaxle gear for the vehicle operating conditions.

The PCM energizes the shift solenoid valves by providing a ground to the solenoid's electrical circuit. This sends current through the coil winding of the solenoid, thereby creating a magnetic field. The magnetic field repels the plunger inside the solenoid. This seats the solenoid metering ball against the fluid inlet port. This action prevents the exhaust of fluid through the solenoid. It then provides an increase in fluid pressure at the end of the shift valves. This fluid pressure initiates an upshift by moving the shift valves.

The shift solenoid valves should energize when the voltage is greater than 7.5 volts and de-energize when the voltage is less than one volt.

SHIFT SOLENOID OPERATION

Vehicle Speed Sensor

The Output Speed Sensor (OSS) is a magnetic inductive pickup that relays information relative to vehicle speed to the PCM. Vehicle speed information is used by the PCM to control shift timing, line pressure, and TCC apply and release.

The OSS mounts in the case at the speed sensor rotor which is pressed onto the differential. An air gap of 0.011-0.062" (0.27-1.57 mm) is maintained between the sensor and the teeth on the speed sensor rotor. The sensor consists of a permanent magnet surrounded by a coil of wire. As the differential rotates, an AC signal is induced in the OSS. Higher vehicle speeds induce a higher frequency and voltage measurement at the sensor.

Input Speed Sensor

The Input Speed Sensor (ISS) is a magnetic inductive pickup that relays information about the transaxle input speed to the PCM. The PCM uses this information to control the line pressure, TCC apply and release, and the transaxle shift patterns. This information is also used to calculate the appropriate operating gear ratios and TCC slippage.

The ISS mounts on the transaxle case under the channel plate next to the drive sprocket. An air gap of 0.010-0.114" (0.26-2.90 mm) is maintained between the sensor and the teeth of the drive sprocket. The sensor consists of a permanent magnet surrounded by a coil of wire. As the drive sprocket is driven by the turbine shaft, an AC signal is induced in the ISS. Higher engine speeds induce a higher frequency and voltage measurement at the sensor.

Park/Neutral Position Switch

The Transaxle Range (TR) switch is part of the Park/Neutral Position (PNP) and back-up lamp switch assembly, which is externally mounted on the transaxle manual shaft. The TR switch contains four internal switches that indicate the gearshift lever position. The PCM supplies ignition voltage to each switch circuit. By grounding one or more of the switch circuits, the PCM detects the selected gear range by the state change of the switch input. See TRANSAXLE RANGE SWITCH LOGIC table.

TRANSAXLE RANGE SWITCH LOGIC (1)

Transaxle Electrical Connector

The transaxle electrical connector is an important part of the transaxle operating system. Any interference with the electrical connection can cause the transaxle to set Diagnostic Trouble Codes (DTC) or affect proper operation.

The following items can affect the electrical connection

1. Bent pins in the connector from rough handling during connection and disconnection.
2. Wires backing away from the pins or coming uncrimped (in either the internal or the external wiring harness).
3. Dirt contamination entering the connector when disconnected.
4. Pins in the internal wiring connector backing out of the connector or pushed out of the connector during reconnection.
5. Excessive transmission fluid leaking into the connector, wicking up into the external wiring harness and degrading the wire insulation.
6. Moisture intrusion in the connector.
7. Low pin retention in the external connector from excessive connection and disconnection of the wiring connector assembly.
8. Pin corrosion from contamination.
9. Damaged connector assembly.

Remember the following points

1. To remove the connector, squeeze the two tabs toward each other and pull straight up without pulling by the wires.
2. Limit twisting or wiggling the connector during removal. Bent pins can occur.
3. Do not pry the connector off with a screwdriver or other tool.
4. Visually inspect the seals to ensure that they are not damaged during handling.
5. To reinstall the external wiring connector, first orient the pins by lining up the arrows on each half of the connector. Push the connector straight down into the transaxle without twisting or angling the mating parts.
6. The connector should click into place with a positive feel and/or noise.
7. Whenever the transaxle external wiring connector is disconnected from the internal harness and the engine is operating, DTCs will set. Clear these DTCs after reconnecting the external connector.

ELECTRONIC CONTROL SYSTEM

PCM constantly monitors all electrical circuits. If PCM detects circuit faults or sensors out of range, it will record a Diagnostic Trouble Code (DTC). If fault continues for a predetermined time, Malfunction Indicator Light (MIL) will illuminate.

If MIL is on all the time, DTC(s) are currently being detected. If MIL is off, but PCM had detected a circuit or sensor fault, DTC(s) will be stored in computer memory.

Stored DTCs may be retrieved from PCM memory using a 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 DTCs are repaired. For additional information on diagnosing and repairing engine related PCM DTCs, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

POWERTRAIN CONTROL MODULE

On"J" body models, PCM is located forward of right front wheel housing, behind front fascia cavity splash shield. On "N" body models, PCM is located below left side of instrument panel, near steering column. PCM utilizes two harness connectors. See CONNECTOR IDENTIFICATION . 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.

LIMP-IN MODE

If sensor input signals are missing or inadequate for transaxle operation, PCM will output preset operating signals to transaxle. Limp-in mode will keep vehicle operational and allow it to be driven with reduced transaxle 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.

SHIFT INTERLOCK SYSTEM

Note. For system description and repair information, see appropriate SHIFT INTERLOCK SYSTEMS article.

PERFORMANCE TESTS

Note. Adaptive parameters should be reset if one of the following repairs have been performed: Transaxle replacement. Replacement of any line pressure actuator. Transaxle overhaul when new clutch plates are installed. Replacing control valve body. To reset adaptive parameters, connect scan tool to Data Link Connector (DLC). Follow prompts on scan tool.

Electrical Function Check

Note. If any of the following checks do not perform properly, record the result for reference after completion of the road test.

Perform this check first, to ensure the electronic transaxle components are connected and functioning properly. If these components are not checked, a simple electrical condition could be mis-diagnosed.

1. Connect the scan tool.
2. Ensure the gearshift lever is in Park and set the parking brake.
3. Start the engine.
4. Verify that the following scan tool data can be obtained and is functioning properly. Data that is questionable may indicate a concern. Engine Speed Transaxle Input Speed (Turbine) Transaxle Output Speed Vehicle Speed Transmission Fluid Pressure (TFP) Manual Valve Position Switch Transaxle Range Commanded Gear (current gear) Pressure Control (PC) Solenoid Reference Current PC Solenoid Actual Current PC Solenoid Duty Cycle Brake Switch Engine Coolant Temperature Transmission Fluid Temperature Throttle Angle Ignition Voltage 1-2 Shift Solenoid 2-3 Shift Solenoid TCC Solenoid Duty Cycle TCC Slip Speed
5. Monitor the brake switch signal while depressing and releasing the brake pedal. The scan tool should display: Closed when the brake pedal is released. Open when the brake pedal is depressed.
6. Harsh engagement may be caused by any of the following conditions: High idle speed. Compare engine idle speed to desired idle speed. Commanded low PC solenoid current. Compare PC solenoid reference current to PC solenoid actual current. A default condition caused by certain DTCs that result in maximum line pressure to prevent slippage.
7. Soft or delayed engagement may be caused by any of the following conditions: Low idle speed. Compare engine idle speed to desired idle speed. Low transmission fluid level. Commanded high PC solenoid current. Compare PC solenoid reference current to PC solenoid actual current. Cold transmission fluid. Check for low transmission fluid temperature.
8. Check the garage shifts. Apply the brake pedal and ensure the parking brake is set. Move the gearshift lever through the following ranges: Park to Reverse, Reverse to Neutral, Neutral to Drive. Pause 2 to 3 seconds in each gear position. Verify the gear engagements are immediate and not harsh.
9. Monitor transaxle range on the scan tool. Apply the brake pedal and ensure the parking brake is set. Move the gearshift lever through all ranges. Pause 2-3 seconds in each range. Return gearshift lever to Park. Verify that all selector positions match the scan tool display.
10. Check throttle angle input. Apply the brake pedal and ensure the parking brake is set. Ensure the gearshift lever is in Park. Monitor throttle angle while increasing and decreasing engine speed with the throttle pedal. The scan tool throttle angle should increase and decrease with engine speed.

Part Throttle Detent Downshift

1. Place the gearshift lever in the "D" (Overdrive) position.
2. Accelerate the vehicle to 40-55 MPH in 4th gear.
3. Quickly increase throttle angle to greater than 50 percent.
4. Verify the following: The TCC releases. The transaxle downshifts immediately to 3rd gear.

Full Throttle Detent Downshift

1. Place the gearshift lever in the "D" (Overdrive) position.
2. Accelerate the vehicle to speeds of 40-55 MPH in 4th gear.
3. Quickly increase throttle angle to 100 percent (WOT).
4. Verify the following: The TCC releases. The transaxle downshifts immediately to 2nd gear.

Manual Downshifts

The shift solenoid valves do not control the 4-3 manual downshift. The 4-3 manual downshift is hydraulic. The 3-2 and 2-1 manual downshifts are electronic. The solenoid states will change during or shortly after a 4-3 downshift is selected.

Manual 4-3 Downshift

Place the gearshift lever in the "D" (Overdrive) position. Accelerate the vehicle to 40-55 MPH in 4th gear. Release the throttle while moving the gearshift lever to 3rd. Verify the following

1. The TCC releases.
2. The transaxle downshifts immediately to 3rd gear.
3. The engine slows the vehicle.

Manual 4-2 Downshift

Place the gearshift lever in the "D" (Overdrive) position. Accelerate the vehicle to 40-45 MPH. Release the throttle while moving the gearshift lever to 2nd. Verify the following

1. The TCC releases.
2. The transaxle downshifts immediately to 2nd gear.
3. The engine slows the vehicle.

Manual 4-1 Downshift

Place the gearshift lever in the "D" (Overdrive) position. Accelerate the vehicle to 40 MPH. Release the throttle while moving the gearshift lever to 1st. Verify the following

1. The TCC releases.
2. The transaxle downshifts immediately to 2nd gear.
3. The engine slows the vehicle.
4. The transaxle downshifts to 1st gear at the calibrated speed, typically 30-40 MPH.

Coasting Downshifts

1. Place the gearshift lever in the "D" (Overdrive) position.
2. Accelerate the vehicle to 4th gear with the TCC applied.
3. Release the throttle and lightly apply the brakes.
4. Verify the following: The TCC releases. Downshifts occur at speeds shown in the shift speed chart. See «SHIFT SPEED SPECIFICATIONS»(ref-155792-S16236618852003062500000) .

Manual Gear Range Selection

Note. Perform the following manual selection tests using 10-15 percent throttle angle.

The shift solenoids control the upshifts in the manual gear ranges.

Reverse

With the vehicle stopped, move the gearshift lever to Reverse. Slowly accelerate the vehicle. Verify that there is no noticeable slip, noise or vibration.

Manual 1st

With the vehicle stopped, move the gearshift lever to 1st. Accelerate the vehicle to 20 MPH. Verify the following

1. No upshifts occur.
2. The TCC does not apply.
3. There is no noticeable slip, noise or vibration.

Manual 2nd

With the vehicle stopped, move the gearshift lever to 2nd. Accelerate the vehicle to 35 MPH. Verify the following

1. The 1-2 shift occurs.
2. The 2-3 shift does not occur.
3. There is no noticeable slip, noise or vibration.

Manual 3rd

With the vehicle stopped, move the gearshift lever to 3rd. Accelerate the vehicle to 40 MPH. Verify the following

1. The 1-2 shift occurs.
2. The 2-3 shift occurs.
3. There is no noticeable slip, noise or vibration.

Scheme 131

Scheme 132

Scheme 133

Poor Acceleration At Low Speed

If the stator is freewheeling at all times, the car tends to have poor acceleration from a standstill. At speeds above 30-35 MPH, the car may act normally. For poor acceleration, you should first determine that the exhaust system is not blocked, and the transaxle is in 1st gear when starting out.

If the engine freely accelerates to high RPM in Neutral, you can assume that the engine and the exhaust system are normal. Check for poor performance in Drive and Reverse to help determine if the stator is freewheeling at all times.

Poor Acceleration At High Speed

If the stator is locked up at all times, performance is normal when accelerating from a standstill. Engine RPM and car speed are limited or restricted at high speeds. Visual examination of the converter may reveal a blue color from overheating.

If the converter has been removed, you can check the stator roller clutch by inserting a finger into the splined inner race of the roller clutch and trying to turn the race in both directions. You should be able to freely turn the inner race clockwise, but you should have difficulty in moving the inner race counterclockwise or you may be unable to move the race at all.

If Shudder Occurs After TCC Has Applied

If shudder occurs after the TCC has applied, most of the time there is nothing wrong with the transaxle.

As mentioned above, the TCC is not likely to slip after the TCC has been applied. Engine problems may go unnoticed under light throttle and load, but they become noticeable after the TCC apply when going up a hill or accelerating. This is due to the mechanical coupling between the engine and the transaxle.

Once TCC is applied, there is no torque converter (fluid coupling) assistance. Engine or driveline vibrations could be unnoticeable before TCC engagement.

Inspect the following components in order to avoid misdiagnosis of TCC shudder. An inspection will also avoid the unnecessary disassembly of a transaxle or the unnecessary replacement of a torque converter.

1. Spark Plugs - Inspect for cracks, high resistance or a broken insulator.
2. Plug Wires - Look in each end. If there is red dust (ozone) or a black substance (carbon) present, then the wires are bad. Also look for a white discoloration of the wire. This indicates arcing during hard acceleration.
3. Coil - Look for a black discoloration on the bottom of the coil. This indicates arcing while the engine is misfiring.
4. Fuel Injector - The filter may be plugged.
5. Vacuum Leak - The engine will not get a correct amount of fuel. The mixture may run rich or lean depending on where the leak occurs.
6. EGR Valve - The valve may let in too much or too little unburnable exhaust gas, and could cause the engine to run rich or lean.
7. MAP/MAF Sensor - Like a vacuum leak, the engine will not get the correct amount of fuel for proper engine operation.
8. Carbon On The Intake Valves - Carbon restricts the proper flow of air/fuel mixture into the cylinders.
9. Flat Cam - Valves do not open enough to let the proper fuel/air mixture into the cylinders.
10. Oxygen Sensor - This sensor may command the engine too rich or too lean for too long.
11. Fuel Pressure - This may be too low.
12. Engine Mounts - Vibration of the mounts can be multiplied by TCC engagement.
13. Axle Joints - Check for vibration.
14. TP Sensor - The TCC apply and release depends on the TP sensor in many engines. If the TP sensor is out of specification, TCC may remain applied during initial engine loading.
15. Cylinder Balance - Bad piston rings or poorly sealing valves can cause low power in a cylinder.
16. Fuel Contamination - This causes poor engine performance.

HYDRAULIC PRESSURE TESTS

Note. Before performing a line pressure check, verify that the pressure control solenoid valve is receiving the correct electrical signal from the PCM.

Note. Scan tool is only able to control pressure control solenoid in Park and Neutral with vehicle stopped. This protects clutches from extremely high or low pressures in Reverse and Drive.

Line Pressure

1. Install a scan tool.
2. Start the engine and set the parking brake.
3. Check for a stored Diagnostic Trouble Code (DTC). See «DIAGNOSTIC SYSTEM CHECK»(ref-155792-S27457265162003062500000) under SELF-DIAGNOSTIC SYSTEM.
4. Repair the vehicle, if necessary.
5. Check the transmission fluid level. See LUBRICATION in appropriate SERVICING article.
6. Check the manual linkage for proper adjustment. See ADJUSTMENTS in appropriate SERVICING article.
7. Turn the engine off. Remove the oil pressure test hole plug and install the pressure gauge. (Scheme 134)
8. Place the gearshift lever in Park and set the parking brake.
9. Start the engine and allow the engine to warm up at idle.
10. Access the Pressure Control (PC) solenoid valve control test on the scan tool.
11. Increase the PC solenoid actual current from zero to one amp in 0.1 amp increments. Allow the pressure to stabilize for five seconds after each pressure change. Read the corresponding line pressure on the pressure gauge.
12. Compare the data to the table. See «LINE PRESSURE SPECIFICATIONS»(ref-155792-S34801133992003062500000) table.
13. If pressure readings differ greatly from the table, see «SYMPTOM DIAGNOSIS»(ref-155792-S27706543652003062500000) under TROUBLE SHOOTING.
14. Shut the engine off. Remove the pressure gauge.
15. Apply sealant (GM P/N 12345382) to the oil pressure test hole plug.
16. Install the oil pressure test hole plug. Tighten the plug to 106 INCH lbs. (12 N.m).

LINE PRESSURE SPECIFICATIONS

Scheme 134

SUMMARY

If no hard DTCs are present, and driveability symptoms or intermittent DTCs exist, attempt diagnosis by symptom, or by testing individual components related to system fault. See TROUBLE SHOOTING and/or COMPONENT TESTS . If no problem is found, verify proper electronic control system circuit operation.

Note. Always clear DTCs once repairs are complete. See CLEARING DIAGNOSTIC TROUBLE CODES . Road test vehicle and retrieve DTCs to determine if complaint or DTC is repaired.

Action Taken By PCM

PCM performs the following if DTC is set

1. Does not illuminate the MIL.
2. Freezes shift adapts from being updated.
3. DTC P0218 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL after 2 consecutive trips with a failure signal.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. Calculates output speed from input speed, engine speed and commanded gear.
5. DTC P0502 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL after 2 consecutive trips with a failure signal.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. Calculates output speed from input speed, engine speed and commanded gear.
5. DTC P0503 will be stored in PCM history.

PCM performs the following if DTC is set

1. Does not illuminate MIL.
2. Records operating conditions and stores this information as failure records.
3. DTC P0705 will be stored in PCM history.

PCM performs the following if DTC is set

1. Does not illuminate MIL.
2. Freezes shift adapts from being updated.
3. Will calculate default transmission fluid temperature based on engine coolant temperature, manifold air temperature and engine run time.
4. DTC P0711 will be stored in PCM history.

PCM performs the following if DTC is set

1. Does not illuminate MIL.
2. Freezes shift adapts from being updated.
3. Will calculate transaxle temperature based on engine coolant temperature, manifold air temperature and engine run time.
4. DTC P0712 will be stored in PCM history.

PCM performs the following if DTC is set

1. Does not illuminate MIL.
2. Freezes shift adapts from being updated.
3. Will calculate transaxle temperature based on engine coolant temperature, manifold air temperature and engine run time.
4. DTC P0713 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL after 2 consecutive trips with a failure reported.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. DTC P0716 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL after 2 consecutive trips with failure reported.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. DTC P0717 will be stored in PCM history.

PCM performs the following if DTC is set

1. Will not light MIL when fault is set.
2. Disregards the brake switch input for TCC scheduling. The PCM then uses throttle position and vehicle speed inputs to determine TCC application and release. Use of these inputs may result in a noticeable harsh apply or abrupt release of the TCC.
3. DTC P0719 will be stored in PCM history.

PCM performs the following if DTC is set

1. Does not illuminate the MIL.
2. DTC P0724 will be stored in PCM history.

PCM performs the following if DTC is set

1. Does not illuminate the MIL.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. DTC P0730 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL after 2 consecutive trips with first failure reported.
2. Inhibits TCC engagement.
3. Freezes shift adapts from being updated.
4. DTC P0741 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL.
2. TCC will be commanded on.
3. Freezes shift adapts from being updated.
4. DTC P0742 will be stored in PCM history.

PCM performs the following if DTC is set

1. Does not illuminate the MIL.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure (zero amps).
4. DTC P0748 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. Inhibits TCC engagement.
5. DTC P0751 will be stored in PCM history.

1. Illuminates MIL after 2 consecutive trips with failure reported.
2. Commands maximum line pressure.
3. Inhibits TCC engagement.
4. Inhibits 3-2 downshifts above 35 MPH.
5. Freezes shift adapts from being updated.
6. DTC P0752 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. Inhibits TCC engagement.
5. DTC P0753 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. Commands immediate shift to 2nd gear.
5. Inhibits TCC engagement.
6. DTC P0756 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. Commands immediate shift to 2nd gear.
5. Inhibits TCC engagement.
6. DTC P0757 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. Commands immediate shift to 2nd gear.
5. Inhibits TCC engagement.
6. DTC P0758 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL after 2 consecutive trips with a failure signal.
2. Freezes shift adapts from being updated.
3. Increases line pressure.
4. Assumes "D" shift pattern.
5. Inhibits TCC engagement.
6. DTC P1810 will be stored in PCM history.

PCM performs the following if DTC is set

1. Does not illuminate the MIL.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. DTC P1811 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL after 2 consecutive trips with a failure signal.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. DTC P1815 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL after 2 consecutive trips with a failure signal.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. DTC P1816 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL after 2 consecutive trips with a failure signal.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. DTC P1817 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL after 2 consecutive trips with a failure signal.
2. Freezes shift adapts from being updated.
3. Commands maximum line pressure.
4. DTC P1818 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL.
2. Inhibits TCC engagement.
3. Freezes shift adapts from being updated.
4. DTC P1860 will be stored in PCM history.

PCM performs the following if DTC is set

1. Illuminates MIL after 2 consecutive trips with a failure signal.
2. Freezes shift adapts from being updated.
3. Inhibits TCC engagement.
4. DTC P1887 will be stored in PCM history after conditions are met during 2 consecutive trips.

COMPONENT RESISTANCE

Connect DVOM between specified terminals at component or at transaxle 20-way connector to transaxle. See CONNECTOR IDENTIFICATION. Measure individual component resistance at specified temperature. See COMPONENT RESISTANCE SPECIFICATIONS table. If resistance is not as specified, replace appropriate component. (Scheme 130)

COMPONENT RESISTANCE SPECIFICATIONS

Scheme 135

Scheme 136

Scheme 137

Scheme 138

Scheme 139

Scheme 140

Scheme 141

Scheme 142

Scheme 143

Scheme 144

Scheme 145

Scheme 146

Scheme 147

Scheme 148

Scheme 149

Scheme 150

Scheme 151

Scheme 152

Scheme 153

Scheme 154

Scheme 155

Scheme 156

Scheme 157

Scheme 158

Scheme 159

Transaxle Electronic Control System Wiring Diagram (Alero & Grand Am - 2.2L). Scheme 160

Transaxle Electronic Control System Wiring Diagram (Alero & Grand Am - 3.4L). Scheme 161

Transaxle Electronic Control System Wiring Diagram (Cavalier & Sunfire - 2.2L). Scheme 162

Transaxle Electronic Control System Wiring Diagram (Malibu - 3.1L). Scheme 163