ABS Indicator Malfunction

ABS Indicator Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.



Circuit/System Description

The instrument panel cluster (IPC) illuminates the antilock brake system (ABS) indicator by supplying ground to the lamp. The electronic brake control module (EBCM) sends a high speed GMLAN serial data message to the body control module (BCM), to request the indicator to turn ON or OFF. The BCM sends the request to the IPC on the class 2 serial data bus.


Reference Information
Schematic Reference

* Antilock Brake System Schematics ([1][2]Antilock Brakes / Traction Control Systems)
* Data Communication Schematics (Electrical Diagrams)
* Instrument Cluster Schematics (Instrument Cluster Schematics)

Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

* ABS Description and Operation (Description and Operation)
* Indicator/Warning Message Description and Operation (Indicator/Warning Message Description and Operation)

Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)for Scan Tool Information


Circuit Verification

Ignition ON. Observe the ABS indicator turn ON then OFF during the IPC bulb test.


Circuit/System Testing

1. Ignition ON. With a scan tool command the IPC display test ON and OFF. The ABS indicator should turn ON and OFF.

• If the ABS indicator does not turn ON and OFF when commanded, replace the IPC.

2. Replace the EBCM.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.


Control Module References (Programming and Relearning)for EBCM or IPC replacement, setup, and programming