Diagnostic Procedure 21

21. TCM Self-diagnosis Does Not Activate (PNP, Overdrive Control and Throttle Position Switches Circuit Check)

SYMPTOM: O/D OFF indicator lamp does not come on in TCM self-diagnostic procedure even the lamp circuit is good.


DESCRIPTION
^ Park/Neutral Position (PNP) Switch



The PNP switch assembly 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 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

NOTE: The diagnostic procedure includes inspections for the overdrive control and throttle position switch circuits.






















COMPONENT INSPECTION
Overdrive Control Switch




^ Check continuity between terminals 5 and 6.
Continuity:
- Switch position ON: No
- Switch position OFF: Yes

Park/Neutral Position (PNP) Switch











1. Check continuity between terminals 1 and 2 and between terminals 3 and 4, 5, 6, 7, 8, 9 while moving manual shaft through each position.





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





4. If NG on step 2, remove park/neutral position (PNP) switch from A/T and check continuity of park/neutral position (PNP) switch terminals. Refer to step 1.
5. If OK on step 4, adjust park/neutral position (PNP) switch. Refer to Park/Neutral Position Switch. Transmission Position Sensor/Switch
6. If NG on step 4, replace park/neutral position (PNP) switch.


Throttle Position Switch
Closed Throttle Position Switch (Idle Position)







^ Check continuity between terminals 4 and 5.
^ To adjust closed throttle position switch, refer to Throttle Position Sensor. Throttle Position Sensor

Wide Open Throttle Position Switch







^ Check continuity between terminals 5 and 6.