SERVICE BRAKE BOOSTER Message
WARNING: This page does not describe the selected car, but rather 12 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, and 2003 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
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.