GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The instrument panel cluster (IPC) illuminates the ABS indicator by supplying ground to the lamp. The electronic brake control module (EBCM) sends serial data messages to the IPC to command the indicator ON or OFF.

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 IPC is able to turn OFF the ABS indicator.

Step

Action

Yes

No

Important: An ECE 13 response may cause the ABS indicator to remain ON when no DTCs are set. It is necessary to verify that ECE 13 is not causing the ABS indicator to remain illuminated, prior to performing this diagnostic. Refer to ABS Description and Operation for a complete description of the ECE 13 response.

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 ABS indicator.

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

Go to Diagnostic Aids

Go to Step 3

3

  1. Select the Instrument Panel Cluster Special Functions menu on the scan tool.
  2. Select Lamp Tests.
  3. Command the IPC indicator lamps Off.

Does the ABS indicator turn OFF?

Go to Step 5

Go to Step 4

4

Replace the instrument panel cluster (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 approximately 2 seconds and then turn OFF?

System OK

Go to Step 3