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 - Hydraulic Brakes before using the brake indicator symptom tables in order to verify that all of the following are true:
  2. • There are no DTCs set.
    • The control modules can communicate via the serial data link.
  3. Review the system operation in order to familiarize yourself with the system functions. Refer to Brake Warning System Description and Operation

Visual/Physical Inspection

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

Intermittent

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

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
    • 50278
    •  Brake Pulsation
    •  Brake System Noise
    •  Braking Action Uneven - Pulls to One Side
    •  Braking Action Uneven - Front to Rear
    •  Brake Pedal Excessive Travel
    •  Brake Pedal Excessive Effort
    •  Brakes Drag
    •  Brake System Slow Release
    •  Brake Fluid Loss