Layout of automatic transmission self-diagnosis system units
1. Main O/D switch; 2. Transmission fluid temperature sensor; 3. Transfer case lock switch; 4. Position sensor L4; 5. Speed sensor N1; 6. Transmission Processor Unit; 7. Speed sensor N₂; 8. Synchronizing solenoid valve; 9. Solenoid valve N1; 10. Transmission lock switch; 11. Solenoid valve N₂; 12. Brake light switch; 13. Junction box; 14. Throttle position sensor; 15. Coolant temperature sensor; 16. Connector 1 data channel; 17. Engine processor unit; 18. Blocking solenoid valve; 19. Gear selection switch
Error codes
| 41 | throttle position sensor or circuit is faulty |
| 42 | speed sensor 1 in the instrument panel is faulty |
| 61 | speed sensor 2 in transmission is faulty |
| 62 | solenoid valve 1 or circuit faulty |
| 63 | solenoid valve 2 or circuit faulty |
| 64 | faulty locking solenoid or circuit |
| 65 | faulty timing solenoid or circuit |
| 86 | the engine speed sensor or circuit is faulty |
| 88 | the engine or transmission processor unit or chain is faulty |
Self-diagnosis (1993-94.)
1. On 1993-94 vehicles, the transmission control unit has a self-diagnostic function. A failure is registered by the O/D OFF lamp lighting up.
2. To read diagnostic codes, turn the ignition switch to the ON position and press the O/D button. The lamp on the switch should light up, and the O/D OFF lamp should also light up.
3. Short-circuit the diagnostic connector terminals TT and E1.
4. Read the codes by the blinking of the O/D OFF lamp. If there is no failure, the lamp blinks with a period of 0.5 sec. If a failure is detected, the first digit of the code will be displayed first, and after 1.5 seconds - the second digit (for example, if the lamp first blinked 4 times, and then 2, then the fault code is 42).
5. After repair, erase the codes from the memory. To do this, remove the 10A DOME fuse for at least 10 seconds. You can also disconnect the battery from the ground, but this will also erase other codes from the memory.
Self-diagnosis (1995-97.)
1. 1995-97 vehicles have OBD II on-board diagnostics and require a special, expensive scanner to read the automatic transmission diagnostic codes.
2. Therefore, it is recommended to have the codes read at a car service center.