Procedure 21

21. TCM Self-diagnosis Does Not Activate (Park/Neutral Position, Overdrive Control and Throttle Position Switch Circuit Checks)
SYMPTOM: O/D OFF indicator lamp does not come on in TCM self-diagnostic procedure even the lamp circuit is good.

DESCRIPTION





- PNP switch
The PNP switch assemble includes a transmission range switch. The transmission range switch detects the selector position and sends a signal to the TCM.





- Overdrive control switch
Detects the overdrive control switch position ("ON" or "OFF") and sends a signal to the TCM.





- Throttle position switch
Consists of a wide open throttle position switch and a closed throttle position switch.
The wide open throttle position switch sends a signal to the TCM when the throttle valve is open at least 1/2 of the full throttle position. The closed throttle position switch sends a signal to the TCM when the throttle valve is fully closed.

DIAGNOSTIC PROCEDURE





Part 1 of 3





Part 2 of 3





Part 3 of 3

COMPONENT INSPECTION
Overdrive control switch








- Check continuity between two terminals.

Park/neutral position switch











1. Check continuity between terminals (1) and (2) and between terminals (3) and (5), (6), (7), (8), (9), (10) while moving manual shaft through each position.





2. If NG, check again with manual control cable disconnected from manual shaft of A/T assembly. Refer to step 1.
3. If OK on step 2, adjust manual control cable.





4. If NG on step 2, remove PNP switch from A/T and check continuity of PNP switch terminals. Refer to step 1.
5. If OK on step 4, adjust PNP switch.
6. If NG on step 4, replace PNP switch.

Throttle position switch
Closed throttle position switch (idle position)








- Check continuity between terminals (5) and (7). (Refer to "Preparation", "TCM SELF-DIAGNOSTIC PROCEDURE (No Tools)". Displaying & Reading Trouble Codes

Wide open throttle position switch








- Check continuity between terminals (6) and (7).