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

IDENTIFICATION

All transaxles have a nameplate attached to the rear face of transaxle case. A transaxle VIN number is also stamped into right rear surface of case. (Scheme 331)

Scheme 331

Test Description

The numbers listed below refer to step numbers in the diagnostic procedure

1. 1) Determines if the scan tool is receiving power through the DLC connector.
2. 2) MIL should illuminate whenever the ignition is on and the engine is not running.
3. 3) Determines if the PCM is transmitting class 2 serial data to the DLC, and that the class 2 data circuit is not open or shorted.
4. 4) Determines if a DTC is current or stored in history.

The number listed below refers to step number in the diagnostic procedure

1. 2) This step ensures that the transmission fluid is at the proper level. A low fluid level may cause an overtemperature condition.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 2) This step tests for DTCs and for a vehicle speed signal. It is important to record freeze frame and failure record information before proceeding further.
2. 5) This step tests for a resistance value less than 1300 ohms which would indicate a short together between the high and the low signal circuits.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 2) This step tests for DTCs and for a vehicle speed signal. It is important to record freeze frame and failure record information before proceeding further.
2. 5) This step tests for a resistance value less than 1300 ohms which would indicate a short together between the high signal circuit and the low signal circuit.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 5) This step tests for an intermittent short or open condition in the engine wiring harness. The test light is used as a resistor in the circuit.
2. 6) This step determines if the PCM or the TFT sensor is causing a steady, unchanging transmission fluid temperature reading.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 2) This step verifies DTC P0712 by indicating a short to ground. If the scan tool does not display a transmission fluid temperature equal to or greater than 300°F (149°C), then the DTC is intermittent.
2. 3) This step isolates the transaxle. If the scan tool displays a transmission fluid temperature less than -36°F (-38°C), then the engine wiring harness is good.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step tests the wiring from the transaxle in-line 20-way connector to the PCM for an open or short to voltage.
2. 4) This step verifies the signal circuit from the PCM to the transaxle in-line 20-way connector.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step tests the ISS for correct resistance.
2. 10) Replace the PCM only after completing all circuit tests.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step tests the ISS for correct resistance.
2. 10) Replacing the PCM only after completing all circuit tests.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 2) Disconnecting the brake switch connector, jumping the circuit, and observing a status change isolates the brake switch as the source of the DTC.
2. 3) If the voltage circuit (1039) shorts to ground, the IGN 1 fuse opens.
3. 5) If the brake switch is properly adjusted, then the brake switch must be replaced.
4. 8) Replace the PCM only after you have completed the preceding diagnostic steps.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 2) Disconnecting the brake switch connector, and observing a status change, isolates the brake switch as the source of the DTC.
2. 3) This step inspects the signal circuit for a short to voltage if the brake switch status on the scan tool did not change in step 2) .
3. 4) If the brake switch is properly adjusted, then the brake switch must be replaced.
4. 5) Replace the PCM only after you have completed the preceding diagnostic steps.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step tests for low fluid level, which may cause slipping, and result in an incorrect gear ratio.
2. 4) This step verifies that the correct 1st gear ratio occurs for commanded 1st gear.
3. 5) This step tests for low line pressure.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step tests for low fluid level, which may cause slipping, and result in an incorrect gear ratio.
2. 4) This step verifies that the correct 2nd gear ratio occurs for commanded 2nd gear.
3. 5) This step tests for low line pressure.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step tests for low fluid level, which may cause slipping, and result in an incorrect gear ratio.
2. 4) This step verifies that the correct 3rd gear ratio occurs for commanded 3rd gear.
3. 5) This step tests for low line pressure.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step tests for low fluid level, which may cause slipping, and result in an incorrect gear ratio.
2. 4) This step verifies that the correct 4th gear ratio occurs for commanded 4th gear.
3. 5) This step tests for low line pressure.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 2) This step inspects the transmission fluid to ensure that it is at the proper level.
2. 3) This step verifies that the TCC engages when commanded on by the scan tool.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 2) This step verifies that the PCM commands the TCC PWM solenoid valve off and the slip speed is -20 to 150 RPM.
2. 3) This step inspects and repairs the components that caused the DTC to set.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 2) This step verifies the ability of the PCM to command the PC solenoid valve.
2. 3) This step verifies that the transaxle wiring harness and the PC solenoid valve have correct resistance.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step verifies a 2-2-3-3 shift pattern.
2. 4) This step tests for a mechanical or hydraulic condition causing the 1-2 shift solenoid valve to be stuck off, or the circuit to be released.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step verifies a 1-1-4-4 shift pattern.
2. 4) This step tests for a mechanical or hydraulic condition causing the 1-2 shift solenoid valve to be stuck on, or the circuit to be applied.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step verifies a 4-3-3-4 shift pattern.
2. 4) This step tests for a mechanical or hydraulic condition causing the 2-3 shift solenoid valve to be stuck on, or the circuit to be applied.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step verifies a 1-2-2-1 shift pattern.
2. 4) This step tests for a mechanical or hydraulic condition causing the 2-3 shift solenoid valve to be stuck off, or the circuit to be released.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step reviews the 1-2 adapt cells. If the pressure readings match or exceed the value listed in the value column, then the PCM modifies the base line pressure on a 1-2 shift. This modification adjusts the holding effort of a clutch or band.
2. 4) This step reviews the 2-3 adapt cells. If pressure readings match or exceed the value listed in the value column, then the PCM modifies the base line pressure on a 2-3 shift. This modification adjusts the holding effort of a clutch or band.
3. 5) This step reviews the 3-4 adapt cells. If pressure readings match or exceed the values listed in the value column, then the PCM modifies the base line pressure on a 3-4 shift. This modification adjusts the holding effort of a clutch or band.
4. 6) This step inspects or repairs any of the components listed. A faulty component may lead to a maximum adapt and long shift during a 1-2 upshift.
5. 7) This step inspects or repairs any of the components listed. A faulty component may lead to a maximum adapt and long shift during a 2-3 upshift.
6. 8) This step inspects or repairs any of the components listed. A faulty component may lead to a maximum adapt and long shift during a 3-4 upshift.
7. 9) This step inspects components located within the control valve body, if the fluid pressure gauge readings do not match the commanded PC solenoid valve current to line pressure located in the value column.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 2) This step inspects the failure records for DTC P1814 occurrences.
2. 4) This step replaces the transmission fluid and filter. If DTC P1814 occurs more than once in the failure records, TCC damage may have occurred.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step determines if the fault is internal or external to the transaxle.
2. 4) This step determines if the engine wiring harness circuit or the PCM is at fault.
3. 5) This step determines if the transaxle wiring harness or the internal mode switch is at fault.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step determines if the fault is internal or external to the transaxle.
2. 4) This step determines if the engine wiring harness circuit or the PCM is at fault.
3. 5) This step determines if the transaxle wiring harness or the internal mode switch is at fault.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step determines if the fault is internal or external to the transaxle.
2. 4) This step determines if the engine wiring harness circuit or the PCM is at fault.
3. 5) This step determines if the automatic transaxle wiring harness or the internal mode switch is at fault.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step tests the internal mode switch for an open ground circuit.
2. 5) This step tests for correct reference voltage from the PCM.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 8) This step tests the electrical operation of the solenoid.
2. 9) This step tests the PCM and the wiring to the transaxle.
3. 14) This step verifies that the circuit has the correct resistance.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step tests the PCM and the wiring to the transaxle.
2. 5) This step verifies that the circuit has the correct resistance.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 8) This step tests the electrical operation of the solenoid.
2. 9) This step verifies the PCM's ability to command the solenoid.
3. 14) This step verifies that the circuit has the correct resistance.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step tests the PCM and the wiring to the transaxle.
2. 5) This step verifies that the circuit has the correct resistance.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 11) This step tests the PCM and the wiring to the transaxle in-line 20-way connector.
2. 14) This step tests the control circuit for a short to voltage.
3. 16) This step tests the circuit for correct resistance.

The number listed below refers to step number in the diagnostic procedure

1. 2) This step changes the transmission fluid and filter. It is important to reset the oil life monitor after the fluid and filter are replaced.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 2) This step tests the indicated range signal to the manual valve range actually selected.
2. 4) This step tests for correct voltage from the PCM.

The numbers listed below refer to step numbers in the diagnostic procedure

1. 3) This step tests the internal mode switch for an open ground circuit.
2. 5) This step tests for correct reference voltage from the PCM.