For 1990-2009 cars

### Circuit Description

The Electronic Brake Control Module (EBCM) turns ON the ABS indicator by grounding the ABS indicator control circuit. The ABS indicator is connected to the GAUGE fuse. This circuit has power when the ignition switch is in the ON or START positions. When the ignition switch is turned to the ON position, the EBCM turns ON the ABS indicator for 3 seconds for a bulb check. If the EBCM detects a malfunction, the ABS indicator will stay ON to warn the driver that the ABS is disabled and needs service.

### Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

• | A short to ground in the ABS Indicator Control circuit

• | A malfunctioning Antilock Indicator Driver Module

• | An internal EBCM malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

### Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. Determines if the malfunction is caused by an internal EBCM malfunction.

2. A short to ground in the ABS Indicator Control circuit will keep the ABS indicator ON.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Antilock Brake System Schematics
1 | Did you perform A Diagnostic System Check - ABS? | Go to Step 2 | Go to Diagnostic System Check - ABS
2 |

1. Turn OFF the ignition.
2. Disconnect the EBCM electrical connector.
3. Turn ON the ignition, with the engine OFF.

Is the ABS indicator ON?

Go to Step 3

Go to Step 5

3 | Test the ABS Indicator Control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 6 | Go to Step 4
4 | Replace the Antilock Indicator Driver Module. Refer to Lamp Driver Module Replacement . Did you complete the replacement? | Go to Step 6 | --
5 | Replace the Brake Pressure Modulator Valve (BPMV). Refer to Brake Pressure Modulator Valve Assembly Replacement . Is the repair complete? | Go to Step 6 | --
6 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2