The amber ABS indicator lamp operates in two modes; normal and backup. In the normal mode, ignition voltage is supplied to the ABS indicator lamp bulb through the IGN SW fuse. Once the ignition is turned on or the vehicle is started the EBCM energizes the ABS indicator lamp relay (normally closed) and ground path for the light through the relay is opened. The EBCM also illuminates the ABS indicator lamp for a 2 second bulb check by suppling ground through connector C2, terminal 1, If the EBCM senses a failure and a DTC is set, it will illuminate the lamp in this manner. In the backup mode, the ABS telltale relay circuit will ensure that the ABS indicator lamp is illuminated if the 24 way connector is disconnected or poorly seated, or if certain EBCM internal failures during normal operation. If either of these conditions occur, the ABS indicator lamp relay closes, which creates an alternate ground path to the ABS indicator lamp circuit through terminal B8 and terminal A7 of the EBCM. This system ensures that the ABS indicator lamp will always be turned on if the following conditions exist:

The ABS is not disabled.

DTC C0286 typically sets because of a shorted ABS indicator lamp. Yet DTC C0286 can also set because of a short to voltage in the wiring between the ABS indicator lamp and the EBCM.

The numbers below refer to the steps in the diagnostic table:

2. This step checks for normal operation of the ABS indicator lamp.

3. This step turns off the ABS indicator lamp with a J 36169-A .