TCM Self-Diagnosis Does Not Activate

TCM Self-diagnosis Does Not Activate (PNP Overdrive Control and Throttle Position Switches 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

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





Chart 1 and 2





Chart 3 and 4





Chart 5 and 6





Chart 7 and 8





Chart 9 - 11

COMPONENT INSPECTION
Overdrive Control Switch





- Check continuity between two terminals.
Continuity:
Switch position "ON": No
Switch position "OFF": Yes

Park/Neutral Position Switch





1 of 3





2 of 3





3 of 3

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 Automatic Transmission/Transaxle; Shift Linkage, A/T.





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. Refer to Powertrain Management; Computers and Control Systems.
6. If NG on step 4, replace PNP switch.

Throttle Position Switch
Closed Throttle Position Switch (Idle Position)





1 of 2





2 of 2

- Check continuity between terminals 5 and 6.
[Refer to "Preparation", "TCM SELF-DIAGNOSTIC PROCEDURE (No Tools)"]
- To adjust closed throttle position switch, refer to Powertrain Management; Computers and Control Systems.

Wide Open Throttle Position Switch





1 of 2





2 of 2

- Check continuity between terminals 4 and 5.

A/T Fluid Temperature Switch
1. Make sure the A/T fluid warning lamp lights when the key is inserted and turned to "ON".
2. Make sure the A/T fluid warning lamp goes off when turning the ignition switch to "ON".





1 of 2





2 of 2

3. Check resistance between terminal 10 and ground while changing temperature as shown.