Malfunction Indicator Lamp: Testing and Inspection

MALFUNCTION INDICATOR LAMP

The diagnosis found here addresses an inoperative lamp condition. If the lamp comes on and stays on with the engine running, refer to Fuel System for diagnosis. If no fuel or emission system problem is found, the following procedure will help locate a short or open in the lamp circuit. For circuit descriptions and diagrams, refer to Wiring Diagrams.

1. Disconnect the battery negative cable. Unplug the PCM connector C (gray). Install a jumper wire between the malfunction indicator lamp driver circuit cavity of the PCM connector C and a good ground. Connect the battery negative cable. Turn the ignition switch to the on position. The lamp should light. Remove the jumper wire and the lamp should go off, If OK, refer to the Powertrain Diagnostic Procedures to diagnose the PCM. If not OK, go to Step 2.

2. Turn the ignition switch to the Off position. Disconnect the battery negative cable. Remove the instrument cluster bezel and the cluster assembly. Install a jumper wire between the malfunction indicator lamp driver circuit cavity of the cluster tell-tale connector and a good ground. Connect the battery negative cable. Turn the ignition switch to the On position. The lamp should light. If OK, go to Step 3. If not OK, replace the faulty bulb.

3. Turn the ignition switch to the off position. Disconnect the battery negative cable. Unplug the cluster tell-tale connector. Check for continuity between the malfunction indicator lamp driver circuit cavity of the tell-tale connector and a good ground. There should be no continuity. If OK, go to Step 4. If not OK, repair the short circuit as required.

4. Check continuity between the malfunction indicator lamp driver circuit cavities of the tell-tale connector and the PCM connector C. There should be continuity. If not OK, repair the open circuit as required.