QG18DE (Except Calif. CA Model)

PCM 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 PCM self-diagnostic procedure even if the lamp circuit is good.

DESCRIPTION





- PNP switch
The PNP switch assembly includes a transmission range switch. The transmission range switch detects the selector lever position and sends a signal to the PCM.





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





- 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 PCM 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 PCM when the throttle valve is fully closed.

Steps 1 - 2:

Steps 3 - 4:

Step 5:

Steps 6 - 7:

DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION








Overdrive Control Switch
- Check continuity between terminals 1 and 2.

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 cable disconnected from manual shaft of A/T assembly. Refer to step 1.
3. If OK on step 2, adjust manual control cable. 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; Transmission Position 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 6.
Refer to "Preparation", "TCM/PCM Self-diagnostic Procedure (No Tools)".
- To adjust closed throttle position switch, refer to Powertrain Mangagement; Computers and Control Systems; Testing and Inspection; Procedures; Trouble Code Diagnostic Procedures; SAE Diagnostic Trouble Codes; P Diagnostic Trouble Codes; DTC P0510 Closed Throttle Position Switch.

Wide open throttle position switch








- Check continuity between terminals 4 and 5.