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.
-
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 | |
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 |
