GM Service Manual Online
For 1990-2009 cars only

Brake Warning Indicator

The instrument panel cluster (IPC) illuminates the brake warning indicator when one or more of the following occurs:

    • The body control module (BCM) detects that the park brake is engaged. The IPC receives a class 2 message from the BCM requesting illumination.
    • The electronic brake control module (EBCM) detects a low brake fluid condition. The IPC receives a class 2 message from the EBCM requesting illumination.
    • The EBCM detects an ABS malfunction which disables dynamic rear proportioning (DRP). The IPC receives a class 2 message from the EBCM requesting illumination.
    • The IPC performs the bulb check at the start of each ignition cycle. The brake warning indicator illuminates for approximately 3 seconds before turning OFF.
    • The IPC detects a loss of class 2 communications with the BCM or with the EBCM.

Service Brake System Message

The service brake system message is displayed whenever the red brake warning indicator is illuminated.

Supplemental Brake Assist

The Supplemental Brake Assist (SBA) displays two messages through the Driver Information Center (DIC).

REDUCED BRAKE POWER

The REDUCED BRAKE POWER message is displayed when the supplemental brake assist signal circuit is held low. This happens when the SBA is active and maintaining reduced brake power levels.

SERVICE BRAKE BOOSTER

The SERVICE BRAKE BOOSTER message will be displayed when the supplemental brake assist signal circuit is toggled at 1.0 Hz with a 50 percent duty cycle. This message is also displayed if the instrument panel cluster (IPC) does not see an alive and well signal at key on. When this message is displayed it indicates a problem with the SBA and should be serviced or replaced.