P0731

AF23-5 AUTOMATIC TRANSAXLE

DTC P0731

Test 1-9:

Test 10-19:

Test 20-26:

Circuit Description with AF23-5 Automatic Transaxle
The transmission control module (TCM) calculates gear ratio based on data from the transmission input shaft speed (ISS) and output shaft speed (OSS) sensors. The TCM compares the calculated gear ratio to the known gear ratio for each commanded gear.

If the TCM detects an incorrect 1st gear ratio, indicating excessive slip or drag within the transmission, then DTC P0731 sets. DTC: P0731 is a type A DTC.

Conditions for Running the DTC
^ No TR switch DTC P0705.
^ No TFT DTCs P0711, P0712, or P0713.
^ No ISS DTC P0717.
^ No OSS DTC P0722.
^ No engine speed DTC P0727.
^ No solenoid DTCs P0962, P0963, P0966, P0967, P0970, P0971, P0973, P0974, P0976, P0977, P0979, P0980, P0982, P0983, P0985, or P0986.
^ No engine torque DTC P1781.
^ No throttle position DTC P1791.
^ No CAN DTCs U2104 or U2105.
^ The ignition voltage is 10.5-18 volts.
^ The brake switch is released.
^ The transmission temperature is greater than 20°C (68°F).
^ Engine torque is between 30 - 200 Nm (22.13 - 147.51 ft. lbs.).
^ The transmission is in a forward range.
^ The elapsed time since the most recent range change is 8 seconds or greater.
^ The engine speed is at least 400 RPM and is at least 150 RPM greater than input shaft speed (ISS) for 0.5 seconds.
^ The commanded gear has been 1st for 0.5 seconds or greater.
^ The transmission input shaft speed (ISS) is 400 RPM or greater.
^ The transmission output shaft speed (OSS) is 200 RPM or greater.

Conditions for Setting the DTC
The TCM commands 1st gear and the actual gear ratio is not within 3.68:1-5.52:1 for 10 seconds.

Action Taken When the DTC Sets
^ The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
^ Inhibit 1st gear.
^ The line pressure is at maximum, and freezes the transmission adapt functions.
^ Inhibit garage shift.
^ The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record.
^ The TCM stores DTC P0731 in TCM history.

Conditions for Clearing the MIL/DTC
^ The ECM turns off the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request.
^ A scan tool can clear the DTC.
^ The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
^ The TCM cancels the DTC default actions when the ignition is OFF long enough in order to power down the TCM.

Diagnostic Aids
Ask the customer about overloading the vehicle, or exceeding the trailer towing limit.

Test Description
The numbers refer to the step numbers on the diagnostic table.
5. This step determines that shift solenoid 4 or the U1 shift valve is stuck if the TCC applies in 2nd gear and stalls the engine.
6. This step determines if the output shaft speed sensor signal is skewed by a large factor.
7. This step determines if the input shaft speed sensor signal is skewed by a large factor.
8. This step determines that shift solenoid 2 or the M2 shift valve is stuck if the TCC Slip Speed is near 0 RPM at idle in DRIVE (D).