GM Service Manual Online
For 1990-2009 cars only

Important: The following steps must be completed before using the symptom tables.

  1. Perform Diagnostic System Check - ABS before using the Symptom Tables in order to verify that all of the following are true:
  2. • There are no DTCs set.
    • The control module(s) can communicate via the serial data link.
  3. Review the system operation in order to familiarize yourself with the system functions. Refer to the following procedures:
  4. •  ABS Description
    •  ABS Operation

Visual/Physical Inspection

    • Inspect for aftermarket devices which could affect the operation of the antilock brake system. Refer to Checking Aftermarket Accessories .
    • Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

    •  ABS Indicator Always On
    •  ABS Indicator Inoperative
    •  Scan Tool Displays Undefined DTC