Automatic Transaxle Diagnosis - 4T80-E: Other Oldsmobile Aurora II

ADAPT FUNCTION

The 4T80-E transaxle uses a line pressure control system that has the ability to adapt line pressure to compensate for normal wear of the following parts

1. The clutch fiber plates.
2. The springs and seals.
3. The apply bands.

The PCM maintains the following adapt parameters for the transaxle

Upshift Adapts

The PCM monitors the Input Speed Sensor (ISS) and the Vehicle Speed Sensor (VSS) during commanded shifts to determine if a shift is occurring too fast or too slow. The PCM adjusts the signal to the Pressure Control (PC) solenoid valve to maintain a set shift feel.

Steady State Adapts

The PCM monitors the ISS and the VSS after a shift, and calculates the amount of shift time in that gear. The PCM then adjusts the signal to the PC solenoid valve to maintain shift time below a set amount.

Clearing Transmission Adaptive Pressure

Note. The transaxle may experience harsh, soft or mushy shifts for up to two days after the adapts are cleared.

Transmission adapts must be cleared whenever the transaxle is overhauled or replaced. To clear transmission adapts, select the following

1. Scan tool
2. SPECIAL FUNCTIONS
3. TRANSMISSION OUTPUT CONTROLS
4. CLEAR TAP

TRANSAXLE COMPONENTS & SYSTEMS

Note. For transaxle electronic component locations (Scheme 381)

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. 4th and low-reverse band assemblies.
4. Forward, coast, 2nd and 3rd multiple disc clutches.
5. Two planetary gear sets.
6. Two sprag clutches (forward and 2nd).
7. One roller clutch (low).
8. Three fluid pumps.
9. Two control valve assemblies.
10. A final drive assembly with a bolted-on case extension.

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 Modulation (TCC PWM) solenoid valve.
3. A Pressure Control (PC) solenoid valve.
4. A Transmission Fluid Temperature (TFT) sensor.
5. Two speed sensors (input shaft and vehicle speed sensors).
6. An internal mode switch.
7. A Transmission Fluid Pressure (TFP) manual valve position switch.
8. A transaxle wiring harness.
9. A transaxle wiring extension harness.

ELECTRONIC COMPONENTS

Note. For transaxle electronic component locations (Scheme 381)

Pressure Control Solenoid Valve

A Pressure Control (PC) solenoid valve (also known as a force motor) is a three-port, spool valve, electronic pressure regulator. The solenoid controls pressure based on a flow of current through its coil-winding. The solenoid controls main line pressure by moving a pressure regulator valve against spring pressure.

The position of the PC solenoid valve is controlled by a combination of two methods: high side control and low side control. One terminal of the solenoid receives a fixed frequency signal of 614.0 Hz. This signal varies in positive duty cycle. This feed circuit is called Force High.

The opposite terminal of the PC solenoid valve is called Force Low. Force Low provides a ground for the solenoid.

This combination of Force High and Force Low circuitry controls the actual current through the PC solenoid valve. This advanced control method assures instantaneous control of line pressure when changes occur in the TP sensor and adaptive learning.

1-2 & 2-3 Shift Solenoid Valves

A shift solenoid valve is a two-port, feed-bleed device consisting of a coil/plunger-ball assembly. The solenoid assembly works with an orifice to pressurize the shift valve end chamber when voltage is applied to its coil. The controlled pressure then moves the shift valve against a spring causing a shift to occur. When voltage is no longer applied, the chamber opens to exhaust and the opposite shift valve action occurs. Shift solenoids eliminate the need for throttle valve and governor pressures to control shift valve operation.

The 4T80-E transmission uses two shift solenoid valves (1-2 and 2-3), which are attached to the lower valve body.

Vehicle Speed Sensor

The Vehicle Speed Sensor (VSS) is mounted on the transaxle case extension facing toward the right wheel. This sensor consists of a permanent magnet surrounded by a coil of wire. The sensor mounts into the extension, and maintains a slight air gap (0.045-0.109") between itself and a rotor which is located on the differential. The VSS measures the speed of the rotor, which contains 31 teeth. As the differential rotates, an AC signal is induced in the VSS. The AC signal varies in frequency and voltage output

1. Low speed Low Hz and voltage amplitude.
2. High speed High Hz and voltage amplitude.

This input is used for TCC, line pressure, shift timing and torque management controls.

Input Speed Sensor

The Input Speed Sensor (ISS) is mounted in the case cover facing the drive sprocket. The sensor consists of a permanent magnet surrounded by a coil of wire. The sensor mounts into the case, and maintains a slight air gap (0.045-0.109") between itself and the drive sprocket. An AC voltage signal is induced in the input sensor by rotating the drive sprocket, which contains 39 teeth cut in its outside diameter. The voltage output and frequency varies with drive sprocket speed

1. Low speed Low Hz and voltage amplitude.
2. High speed High Hz and voltage amplitude.

Inside the PCM, this analog signal changes to a digital signal. The processor then compares this digital signal to a fixed clock signal within the PCM to determine the actual turbine speed. The PCM uses input speed for control of line pressure, speed calculation and gear ratio.

Internal Mode Switch

The internal mode switch is a multi-signal switch assembly attached to the lower control valve body. The internal mode switch consists of a set of stationary contacts and a set of sliding contacts. The manual valve link assembly connects the sliding contacts to the manual valve. Electrically, the stationary contacts are connected to ground through the internal mode switch ground circuit, and the sliding contacts are connected to the PCM through four internal mode switch signal circuits. The signal voltage at the PCM is high (ignition voltage) when a signal circuit is open, and low (zero volts) when a signal circuit is closed to ground. Each gearshift lever position grounds one or more of the signal circuits in a unique pattern that enables the PCM to determine gearshift lever position. See INTERNAL MODE SWITCH LOGIC table.

INTERNAL MODE SWITCH LOGIC (1)

Transaxle Electrical Connector

The transaxle in-line 20-way 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. 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.

Scheme 381

POWERTRAIN CONTROL MODULE

PCM controls ignition, fuel and emission devices related to engine and transaxle operation. PCM receives electronic signals from sensors and switches. Input signals enable PCM to determine when to operate various relays and solenoids related to engine and transaxle control. PCM utilizes 2 different colored 80-way connectors. (Scheme 386)- (Scheme 389).

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) may illuminate if malfunction occurs. Vehicle should not be driven for extended periods in limp-in mode.

ELECTRONIC CONTROL SYSTEM

The PCM constantly monitors the information from various sensors and controls the systems that affect vehicle performance and emissions. The PCM also performs the diagnostic functions for those systems. The PCM can recognize operational problems and alert the driver through the Malfunction Indicator Lamp (MIL) when a malfunction has occurred. When a malfunction is detected, the PCM stores a Diagnostic Trouble Code (DTC) which helps to identify problem areas. This is done to aid the technician in making repairs.

SHIFT INTERLOCK SYSTEM

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

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. Check the garage shifts as follows: Apply the brake pedal and ensure the parking brake is set. Move the gearshift lever from Park to Reverse, Reverse to Neutral, then Neutral to Drive. Pause 2 to 3 seconds in each gear position. Verify the gear engagements are immediate and not harsh.
7. Monitor transaxle range on the scan tool as follows: Apply the brake pedal and ensure the parking brake is set. Move the gearshift lever through all ranges. Pause 2 to 3 seconds in each range. Return gearshift lever to Park. Verify that all gearshift lever positions match the scan tool display.
8. Check throttle angle input as follows: 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 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 Overdrive position.
2. Accelerate the vehicle to speeds of 40-55 MPH in 4th gear.
3. Quickly increase throttle angle to 100 percent.
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 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 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 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 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-138270-S18459201732002040200000) .

Manual Gear Range Selection (Reverse)

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

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 Gear Range Selection (1st)

Note. Perform the following test using 10-15 percent throttle angle.

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 Gear Range Selection (2nd)

Note. Perform the following test using 10-15 percent throttle angle.

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 Gear Range Selection (3rd)

Note. Perform the following test using 10-15 percent throttle angle.

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 382

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.

Line Pressure

Line pressures are calibrated for two sets of gear ranges: Drive, Park or Neutral, and Reverse. This allows the transmission line pressure to be appropriate for different pressure needs in different gear ranges. See LINE PRESSURE RANGE SPECIFICATIONS table.

1. Hook up the scan tool.
2. Start the engine and set the parking brake.
3. Check for a DTC P0748 malfunction code from the pressure control solenoid. Check for other malfunction codes.
4. Repair the vehicle if necessary. Include the following areas: Inspect the fluid level. See «LUBRICATION»(ref-138539-S19854199902002041500000) in AUTOMATIC - AURORA article in TRANSMISSION SERVICING. Inspect the manual linkage at the transaxle. Install the pressure gauge adapter. See «LINE PRESSURE ADAPTER & GAUGE INSTALLATION»(ref-138270-S26262373592002040200000) .
5. Put the gearshift lever in Park and set the parking brake.
6. Start the engine and allow the engine to warm up at idle.
7. Select SPECIAL FUNCTIONS on the scan tool.
8. Select TRANS OUTPUT CONTROLS/PRESSURE CONTROL SOLENOID on the scan tool.
9. Compare your data to line pressure specifications. See «PC SOLENOID CURRENT & LINE PRESSURE SPECIFICATIONS»(ref-138270-S21764941932002040200000) table. This line pressure is valid for PC solenoid overrides with the vehicle stopped at idle and in Park or Neutral.

If pressure readings differ greatly from the line pressure specifications, see SYMPTOM DIAGNOSIS under TROUBLE SHOOTING.

LINE PRESSURE RANGE SPECIFICATIONS

PC SOLENOID CURRENT & LINE PRESSURE SPECIFICATIONS

CLUTCH & SERVO AIR CHECKS

Note. For additional information, refer to overhaul procedures. See appropriate OVERHAUL article.

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 actions if DTC is set

1. The PCM does not illuminate the MIL.
2. TRANSMISSION HOT message displays on the driver information center.
3. The PCM freezes shift adapt functions.
4. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
5. The PCM stores DTC P0218 in PCM history.

The PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM freezes shift adapt functions.
4. The PCM calculates vehicle speed from the ISS and commanded gear.
5. The PCM applies the TCC in 3rd gear when in hot mode.
6. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
7. The PCM stores DTC P0502 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM freezes shift adapt functions.
4. The PCM calculates vehicle speed from the ISS and commanded gear.
5. The PCM applies the TCC in 3rd gear when in hot mode.
6. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
7. The PCM stores DTC P0503 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM does not illuminate the MIL.
2. The PCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time.
3. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
4. The PCM stores DTC P0711 in PCM history.

PCM performs the following if DTC is set

1. The PCM does not illuminate the MIL.
2. The PCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time.
3. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
4. The PCM stores DTC P0712 in PCM history.

PCM performs the following if DTC is set

1. The PCM does not illuminate the MIL.
2. The PCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time.
3. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
4. The PCM stores DTC P0713 in PCM history.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM inhibits TCC engagement.
4. The PCM calculates input shaft speed from vehicle speed and commanded gear.
5. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
6. The PCM stores DTC P0716 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM inhibits TCC engagement.
4. The PCM calculates input shaft speed from vehicle speed and commanded gear.
5. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
6. The PCM stores DTC P0717 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM does not illuminate the MIL.
2. The PCM disregards the TCC 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. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
4. The PCM stores DTC P0719 in PCM history.

PCM performs the following if DTC is set

1. The PCM does not illuminate the MIL.
2. The PCM turns off the Brake Transmission Shift Interlock (BTSI) solenoid.
3. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
4. The PCM stores DTC P0724 in PCM history.

PCM performs the following actions if DTC is set

1. The PCM does not illuminate the MIL.
2. The PCM commands maximum line pressure.
3. The PCM freezes shift adapt functions.
4. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
5. The PCM stores DTC P0731 in PCM history.

PCM performs the following actions if DTC is set

1. The PCM does not illuminate the MIL.
2. The PCM commands maximum line pressure.
3. The PCM freezes shift adapt functions.
4. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
5. The PCM stores DTC P0732 in PCM history.

PCM performs the following actions if DTC is set

1. The PCM does not illuminate the MIL.
2. The PCM commands maximum line pressure.
3. The PCM freezes shift adapt functions.
4. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
5. The PCM stores DTC P0733 in PCM history.

PCM performs the following actions if DTC is set

1. The PCM does not illuminate the MIL.
2. The PCM commands maximum line pressure.
3. The PCM freezes shift adapt functions.
4. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
5. The PCM stores DTC P0734 in PCM history.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM inhibits 4th gear if the transaxle is in hot mode.
3. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
4. The PCM stores DTC P0741 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM inhibits TCC engagement.
3. The PCM freezes shift adapt functions.
4. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
5. The PCM stores DTC P0742 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM does not illuminate the MIL.
2. The PCM commands maximum line pressure.
3. The PCM freezes shift adapt functions.
4. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
5. The PCM stores DTC P0748 in PCM history.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM inhibits TCC engagement.
4. The PCM freezes shift adapt functions.
5. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
6. The PCM stores DTC P0751 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following actions if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM inhibits TCC engagement.
4. The PCM inhibits 3-2 downshifts above 31 MPH.
5. The PCM freezes shift adapt functions.
6. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
7. The PCM stores DTC P0752 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL.
2. The PCM commands an immediate landing to 2nd gear.
3. The PCM commands maximum line pressure.
4. The PCM inhibits TCC engagement.
5. The PCM freezes shift adapt functions.
6. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
7. The PCM stores DTC P0756 in PCM history.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL.
2. The PCM commands an immediate landing to 2nd gear.
3. The PCM commands maximum line pressure.
4. The PCM inhibits TCC engagement.
5. The PCM freezes shift adapt functions.
6. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
7. The PCM stores DTC P0757 in PCM history.

PCM performs the following if DTC is set

1. The PCM does not illuminate the MIL.
2. The PCM commands maximum line pressure.
3. The PCM freezes shift adapt functions.
4. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
5. The PCM stores DTC P1811 in PCM history.

PCM performs the following actions if DTC is set

1. The PCM does not illuminate the MIL.
2. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
3. The PCM stores DTC P1814 in PCM history.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM assumes a "D4" shift pattern.
4. The PCM freezes shift adapt functions.
5. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
6. The PCM stores DTC P1820 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM assumes a "D4" shift pattern.
4. The PCM freezes shift adapt functions.
5. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
6. The PCM stores DTC P1822 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM assumes a "D4" shift pattern.
4. The PCM freezes shift adapt functions.
5. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
6. The PCM stores DTC P1823 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM assumes a "D4" shift pattern.
4. The PCM freezes shift adapt functions.
5. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
6. The PCM stores DTC P1825 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM inhibits 3-2 downshifts above 31 MPH.
4. The PCM commands the TCC on in 3rd and 4th gear when in hot mode, if the brake switch status remains closed and no downshifts are commanded.
5. The PCM freezes shift adapt functions.
6. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
7. The PCM stores DTC P1842 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM commands maximum line pressure.
3. The PCM inhibits 3-2 downshifts above 31 MPH.
4. The PCM commands the TCC on in 3rd and 4th gear when in hot mode, if the brake switch status remains closed and no downshifts are commanded.
5. The PCM freezes shift adapt functions.
6. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
7. The PCM stores DTC P1843 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL.
2. The PCM commands an immediate landing to 2nd gear.
3. The PCM commands maximum line pressure.
4. The PCM inhibits TCC engagement.
5. The PCM freezes shift adapt functions.
6. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
7. The PCM stores DTC P1845 in PCM history.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL.
2. The PCM commands an immediate landing to 2nd gear.
3. The PCM commands maximum line pressure.
4. The PCM inhibits TCC engagement.
5. The PCM freezes shift adapt functions.
6. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
7. The PCM stores DTC P1847 in PCM history.

PCM performs the following if DTC is set

1. The PCM illuminates the MIL during the second consecutive trip in which the conditions for setting the DTC are met.
2. The PCM inhibits 4th gear when the transaxle is in hot mode.
3. The PCM freezes shift adapt functions.
4. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as freeze frame and failure records.
5. The PCM stores DTC P1860 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

PCM performs the following actions if DTC is set

1. The PCM does not illuminate the MIL.
2. CHANGE TRANSMISSION FLUID displays on the driver information center.
3. The PCM records the operating conditions when the conditions for setting the DTC are met. The PCM stores this information as failure records.
4. The PCM stores DTC P1868 in PCM history.

TRANSAXLE RANGE SELECTOR DISPLAYS INCORRECT RANGE

Note. For circuit identification, see CONNECTOR IDENTIFICATION and/or WIRING DIAGRAMS .

Note. Manufacturer does not provide on-vehicle removal and installation procedure for this component. See appropriate OVERHAUL article.

Note. Manufacturer does not provide on-vehicle removal and installation procedure for this component. See appropriate OVERHAUL article.

Note. Manufacturer does not provide on-vehicle removal and installation procedure for this component. See appropriate OVERHAUL article.

SHIFT SOLENOID VALVES

Note. Manufacturer does not provide on-vehicle removal and installation procedure for this component. See appropriate OVERHAUL article.

TCC PULSE WIDTH MODULATION SOLENOID VALVE

Note. Manufacturer does not provide on-vehicle removal and installation procedure for this component. See appropriate OVERHAUL article.

TFP MANUAL VALVE POSITION SWITCH

Note. Manufacturer does not provide on-vehicle removal and installation procedure for this component. See appropriate OVERHAUL article.

Note. Removal and installation of vehicle speed sensor and input speed sensor is an un-bolt and bolt-on procedure. Only torque specifications are given. See TORQUE SPECIFICATIONS .

COMPONENT RESISTANCE

Connect DVOM between specified terminals at component or at transaxle in-line 20-way connector to transaxle. Measure individual component resistance at specified temperature. See COMPONENT RESISTANCE SPECIFICATIONS table. If resistance is not as specified, replace appropriate component. (Scheme 381)

COMPONENT RESISTANCE SPECIFICATIONS

Scheme 383

Scheme 384

Scheme 385

Scheme 386

Scheme 387

Scheme 388

Scheme 389

Scheme 390

Scheme 391

Scheme 392

Scheme 393

Scheme 394

Scheme 395

Scheme 396

Scheme 397

Scheme 398

Scheme 399

Scheme 400

Scheme 401

Transaxle Electronic Control System Wiring Diagram (2001-02 Aurora - 4.0L). Scheme 402