GM Service Manual Online
For 1990-2009 cars only

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

  1. Perform the Diagnostic System Check - Vehicle , before using the hydraulic brake symptom tables in order to duplicate the customers concern.
  2. Perform the ABS Diagnostic System Check before using the symptom tables in order to verify that all of the following are true:
  3.    • There are no DTCs set.
       • The control modules can communicate via the serial data link.
  4. Review the system description and operation in order to familiarize yourself with the system functions. Refer to the following:
  5.    •  Brake Warning System Description and Operation
       •  Hydraulic Brake System Description and Operation
       •  Brake Assist System Description and Operation
       •  Disc Brake System Description and Operation

Visual/Physical Inspection

    • Inspect for aftermarket devices which could affect the operation of the Hydraulic 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.
    • Inspect the brake fluid reservoir for the proper brake fluid level.
    • Inspect the power steering fluid reservoir for the proper power steering fluid level.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

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

    •  Brake Warning Indicator Always On
    •  Brake Warning Indicator Inoperative
    •  Service Brake Soon Indicator Always On
    •  Service Brake Soon Indicator Inoperative