GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The instrument cluster controls the operation of the ABS indicator. The electronic brake control module (EBCM) reports the desired status of the ABS indicator via serial data messages.

Diagnostic Aids

The malfunction must be present during diagnosis in order to prevent unnecessary parts replacement. Always begin diagnosis with Diagnostic System Check - Vehicle in Vehicle DTC Information.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step tests if the instrument panel cluster (IPC) is able to turn OFF the ABS indicator.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views or Instrument Panel, Gages, and Console Connector End Views in Instrument Panel, Gages, and Console

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn OFF the ignition for 5 seconds.
  2. Turn ON the ignition while observing the antilock brake system (ABS) indicator.

Does the ABS indicator illuminate for 2 seconds and then turn OFF?

Go to Diagnostic Aids

Go to Step 3

3

  1. Install a scan tool.
  2. Select the Instrument Panel Cluster Special Functions menu on the scan tool.
  3. Command the instrument panel cluster (IPC) Lamps OFF.

Does the ABS indicator turn OFF?

Go to Step 5

Go to Step 4

4

Replace the IPC. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 6

--

5

Replace the electronic brake control module (EBCM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 6

--

6

  1. Turn OFF the ignition for 5 seconds.
  2. Turn ON the ignition while observing the ABS indicator.

Does the ABS indicator illuminate for 2 seconds and then turn OFF?

System OK

Go to Step 3