Inspection Procedure 4

Service Engine Soon/Malfunction Indicator Lamp Circuit:

Connector: C-89:

CIRCUIT OPERATION
- The service engine soon/malfunction indicator lamp power is supplied from the ignition switch.
- The PCM controls the ground of the service engine soon/malfunction indicator lamp by turning the power transistor in the PCM "ON" and "OFF".

COMMENT
- In cases such as the above, the cause is probably that the PCM is detecting a problem in a sensor or actuator.

TROUBLESHOOTING HINTS
The most likely causes for this case:
- Short-circuit between the service engine soon/malfunction indicator lamp and PCM.
- Malfunction of the PCM.

DIAGNOSIS

CAUTION: To prevent damage to the scan tool, turn the ignition switch "OFF" before connecting or disconnecting the scan tool.




STEP 1. Using scan tool MB991502, read the diagnostic trouble code (DTC).
If DTC is not output, go to Step 2.

If DTC is output, refer to Diagnostic Trouble Code Chart.




STEP 2. Check the circuit at the combination meter connector C-04.
1. Disconnect connector C-04 and measure at the harness side.
2. Disconnect the PCM connector C-89.
3. Check for continuity between connector C-04 terminal 23 and ground.

- There should be no continuity.

If there is continuity, repair the harness wire between the combination meter connector C-04 and the PCM connector C-89.

If there is no continuity, replace the PCM.

Then confirm that the malfunction symptom is eliminated.