For 1990-2009 cars

### Circuit Description

The Electronic Brake Control Module (EBCM) controls the operation of the amber ABS indicator lamp by means of a lamp driver module.

When the ignition switch is turned to the ON position, the EBCM turns ON the ABS indicator for 3 seconds for a bulb check. Whenever a malfunction is detected within the ABS system, the EBCM turns ON the ABS indicator, notifying the driver that ABS needs to be serviced.

### 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 lamp 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 below refers to the step number on the diagnostic table.

1. Determines whether there is a short to ground in the ABS indicator circuit or a malfunctioning EBCM.

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 lamp driver module. Refer to Lamp Driver Module Replacement . Did you complete the replacement? | Go to Step 6 | --
5 | Replace the EBCM. Refer to Electronic Brake Control Module 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