Reading and Clearing Diagnostic Trouble Codes

The transmission control module (TCM) with on-board diagnostic system (self-diagnosis function) operates as described below.
When diagnosing a trouble in the electronic shift control system, refer to Diagnostic Charts.

ON-BOARD DIAGNOSTIC SYSTEM (SELF-DIAGNOSIS FUNCTION)





- When the engine is OFF and the ignition switch is turned ON, the "O/D OFF" light lights for 4 seconds for its bulb check of "O/D OFF" light. (It remains ON when O/D cut switch is ON.)
- Should an abnormality have occurred in the electronic shift control system while the ignition switch is ON or the engine running, the "O/D OFF" light flashes to warn occurrence of an abnormality to the driver and at the same time the area where the abnormality has occurred is stored in the TCM memory and it remains in the memory even when the ignition switch is turned OFF.
- The affected area in the memory is indicated by flashing of "O/D OFF" light when the diag. switch terminal is grounded.





- Once stored in the TCM, the trouble code will not be erased unless the power to the TCM is turned OFF longer than 10 seconds.

PRECAUTION IN IDENTIFYING DIAG. TROUBLE CODE
- Before checking the diag. trouble code, be sure not to disconnect the TCM or battery negative cable. Or the memory will be erased.
- Each trouble code is indicated 3 times. Write it down so as not to forget it. When an abnormality exists in more than one area, their code Nos. are indicated from the smallest to larger numbers.

PRECAUTION ON TROUBLESHOOTING
- "Normal operating temperature" in the diagnostic flow chart means that the engine coolant temperature is 80°C (176°F) and A/T fluid temperature is 70-80°C (158-176°F).
- Do not connect an ohmmeter, voltmeter, etc. directly (with the coupler disconnected) to the TCM terminal. It may cause damage to the TCM.