Automatic Transaxle Diagnosis - 4T65-E: Overview Oldsmobile Aurora II

IDENTIFICATION

Transaxle has a metal identification plate or Service Replacement Transmission Assembly (SRTA) plate attached to rear face of transaxle. (Scheme 234) Transaxle RPO code is MN3. The MN3 is a heavy duty model and has a 10.2" (258 mm) torque converter.

Scheme 234

DESCRIPTION & OPERATION

Note. For additional information on transaxle operation, see appropriate OVERHAUL article.

ELECTRONIC COMPONENT DESCRIPTION

Note. For transaxle electronic component locations see scheme 2

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.
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. 3 This step tests the ability of the VSS to produce an AC voltage. This step also verifies the integrity of the wiring to the PCM.
2. 4 This step tests the VSS circuit for correct resistance.

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

1. 3 This step tests ability of VSS to produce AC voltage. This step also verifies integrity of wiring to PCM.
2. 4 This step tests VSS circuit for correct resistance.

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

1. 3 This step attempts to repeat the condition that set the DTC.
2. 5 This step attempts to repeat the condition in the engine wiring harness.
3. 6 This step determines if a condition exists with the PCM or TFT sensor.

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

1. 2 A value below 0.2 volts indicates the fault is present. A value above 0.2 volts indicates the fault is intermittent.
2. 3 A value greater than 4.9 volts indicates the fault is in the transaxle side.
3. 5 For resistance at other temperatures see scheme 59
4. 6 A value less than 10 k/ohms indicates a short to ground in the harness or sensor. A value greater than 10 k/ohms indicates the condition is intermittent.
5. 7 A value less than 10 k/ohms indicates a short together between the TFT signal and ground circuits.

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

1. 2 A value above 4.9 volts indicates the fault is present. A value below 4.9 volts indicates the fault is intermittent.
2. 3 A value of 4.9-5.0 volts indicates the PCM and engine side of the wiring are good.
3. 6 A short to voltage greater than 5 volts would cause the TFT sensor to open.
4. 9 A short to the TFT sensor signal circuit and any other circuits in the transaxle harness could cause the TFT sensor to open.

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

1. 2 This step checks if the PCM receives a signal from the ISS.
2. 3 A Yes answer indicates that the transaxle side of the circuit is functioning properly.
3. 5 Although the resistance is within specification in step 3, there may be a short to ground or a short to power condition.
4. 8 This step begins the transaxle harness diagnosis.

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

1. 2 This step checks if the PCM receives a signal from the ISS.
2. 3 A Yes answer indicates that the transaxle side of the circuit is functioning properly.
3. 4 This step checks the engine harness from the transaxle in-line 20-way connector to the PCM.
4. 8 This step begins the transaxle harness diagnosis.

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

1. 6 This step isolates the fault between the TCC brake switch and the harness.

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

1. 3 If the scan tool indicates CLOSED in step 2, and OPEN when the TCC brake switch is disconnected, the switch is stuck closed.

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 undefined gear ratio.
2. 4 This step verifies that the correct gear ratios occur for commanded gears.
3. 5 This step tests for low line pressure.

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

1. 5 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 A YES answer indicates that the TCC is functioning properly.
2. 3 With the 20-way connector disconnected, the PCM should interpret the open circuit as TCC release pressure present.
3. 4 An open condition in the TCC release circuit or switch would set DTC P1887. Open circuits are not diagnosed in DTC P0742.
4. 7 This step tests for a mechanical or hydraulic condition that would cause the TCC to be stuck on.

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

1. 2 This step verifies that the fault is present.
2. 3 This step tests the transaxle wiring harness and the PC solenoid valve for correct resistance.
3. 9 This step begins diagnosis of the engine side of the circuit.

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

1. 3 This step confirms that the PCM commanded all shifts, but all the shifts did not occur.

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

1. 3 This step confirms that the PCM commanded all shifts, but all the shifts did not occur.

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

1. 2 A short to ground in the power feed circuit to the solenoid ahead of the splice would open the fuse and set DTCs for other solenoids on the same circuit. An open in the same circuit would not open the fuse but, would set the other DTCs.

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

1. 3 This step confirms that the PCM commanded all shifts, but all the shifts did not occur.

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

1. 3 This step confirms that the PCM commanded all shifts, but all the shifts did not occur.

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

1. 2 A short to ground in the power feed circuit to the solenoid ahead of the splice would open the fuse and set DTCs for other solenoids on the same circuit. An open in the same circuit would not open the fuse, but would set the other DTCs.

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

1. 3 This step tests the indicated range signal to the manual valve range actually selected.
2. 6 This step tests for correct voltage from the PCM to the transaxle in-line 20-way connector.
3. 7 This step tests for a short together between signal circuit "A" and signal circuits "B" or "C".

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

1. 7 This step inspects components that may cause low line pressure.
2. 9 This step inspects or repairs components that may cause a maximum adapt and long 1-2 upshift.
3. 11 This step inspects or repairs components that may cause a maximum adapt and long 2-3 upshift.
4. 13 This step inspects or repairs components that may cause a maximum adapt and long 3-4 upshift.

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 fluid and the filter. If DTC P1814 occurs more than once in the failure records, severe TCC damage may have occurred.

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

1. 3 HI values for all signals in both Park and D4 ranges indicates the ground circuit is open.
2. 5 With the 20-way connector disconnected, all signals should indicate HI.
3. 7 If one circuit affects the other, this indicates a short between the two circuits.
4. 13 This step tests the internal transaxle harness. If no fault is found in the harness, the fault will be in the switch.

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

1. 3 A low value for Signal "A" indicates a short to ground in the engine harness or the PCM.
2. 5 This step tests the internal transaxle harness. A value of LOW for Signal "A" indicates the fault is in the harness. Otherwise the fault will be in the switch.

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

1. 3 This step tests the integrity of the engine harness and PCM by checking for the Signal "B" state change from HI to LOW. A LOW signal indicates the fault is either in the internal transaxle harness or the switch. A HI signal indicates the fault is either in the engine harness or the PCM.

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

1. 3 A LOW signal indicates a short to ground in the vehicle harness or the PCM.
2. 5 This step tests the internal transaxle harness without the IMS connected.

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

1. 3 HI values for all signals in all ranges indicates the ground circuit is open.
2. 4 With the 20-way connector disconnected, all signals should indicate HI.
3. 6 If one circuit affects the other, this indicates a short between the two circuits.
4. 13 This step tests the internal transaxle harness. If no fault is found in the harness, the fault will be in the switch.

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

1. 3 This step tests the integrity of the engine harness and PCM by checking for the Signal "C" state change from HI to LOW. A LOW signal indicates the fault is either in the internal transaxle harness or the switch. A HI signal indicates the fault is either in the engine harness or the PCM.

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

1. 2 A short to ground in the power feed circuit to the solenoid ahead of the splice would open the fuse and set DTCs for other solenoids on the same circuit. An open in the same circuit would not open the fuse but would set the other DTCs.

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

1. 3 This step tests the PCMs ability to recognize a grounded circuit.
2. 4 A short to ground in this circuit would set DTC P0742.
3. 5 A short to ground in this circuit would set DTC P0742.