ABS Light: Testing and Inspection

The diagnosis found here addresses an inoperative Antilock Brake System (ABS) indicator lamp condition. If there are problems with several indicator lamps in the instrument cluster, (Refer to INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). If the ABS indicator lamp stays ON with the ignition switch in the ON position or comes ON and stays ON while driving. If no ABS problem is found, the following procedure will help to locate a short or open in the ABS indicator lamp circuit.

WARNING: ON VEHICLES EQUIPPED WITH AIRBAGS, DISABLE THE AIRBAG SYSTEM BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. DISCONNECT AND ISOLATE THE BATTERY NEGATIVE (GROUND) CABLE, THEN WAIT TWO MINUTES FOR THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE BEFORE PERFORMING FURTHER DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.

1. Disconnect and isolate the battery negative cable. Remove the instrument cluster. Reconnect the battery negative cable. Turn the ignition switch to the ON position and within about two seconds check for continuity between the ABS warning indicator driver circuit cavity of the instrument panel wire harness connector (Connector C1) for the instrument cluster and a good ground. There should be continuity for about two seconds after ignition ON, and then an open circuit. If OK, replace the faulty ABS indicator lamp bulb. If not OK, go to Step 2.
2. Turn the ignition switch to the OFF position. Disconnect and isolate the battery negative cable. Remove the Controller Antilock Brake (CAB) relay from the receptacle in the Power Distribution Center (PDC). Check for continuity between the ABS warning indicator driver circuit cavity of the instrument panel wire harness connector (Connector C1) for the instrument cluster and a good ground. There should be no continuity. If OK, go to Step 3. If not OK, repair the shorted ABS warning indicator driver circuit between the instrument cluster and the PDC as required.
3. Check for continuity between the ABS warning indicator driver circuit cavities of the instrument panel wire harness connector (Connector C1) for the instrument cluster and the CAB relay receptacle in the PDC. There should be continuity. If not OK, repair the open ABS warning indicator driver circuit between the instrument cluster and the PDC as required.