Inspection Procedure 4
INSPECTION PROCEDURE 4The Check Engine/Malfunction Indicator Lamp Remains Illuminated and Never Goes Out.
WIRING DIAGRAM and CONNECTOR VIEW
CIRCUIT OPERATION
- The check engine/malfunction indicator lamp power is supplied from the ignition switch.
- The ECM controls the ground of the check engine/malfunction indicator lamp by turning the power transistor in the ECM "ON" and "OFF."
COMMENT
- In cases such as the above, the cause is probably that the ECM is detecting a problem in a sensor or actuator or that one of the malfunctions listed at right has probably occurred.
TROUBLESHOOTING HINTS
The most likely causes for this case:
- Short-circuit between the check engine/malfunction indicator lamp and ECM.
- Malfunction of the ECM.
DIAGNOSIS
STEP 1. Using scan tool MB991502, read the diagnostic trouble code (DTC).
CAUTION: To prevent damage to the scan tool, turn the Ignition switch "OFF" before connecting or disconnecting the scan tool.
If DTC is not output, go to Step 2.
If DTC is output, refer to Inspection Chart for Diagnostic Trouble Code.
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 ECM connector C-53.
(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 ECM connector C-53.
If there is no continuity, replace the ECM. Then confirm that the malfunction symptom is eliminated.