Circuit/System Description
WARNING: This page is about a different car, the 2010 Chevrolet HHR. However, it is still accessible from the selected car via links, so may be relevant.
The instrument panel cluster (IPC) momentarily illuminates the antilock brake system (ABS) indicator during the bulb check when the ignition is cycled ON. When the electronic brake control module (EBCM) detects a fault requiring ABS indicator ON, it sends a serial data message to the IPC to illuminate the ABS indicator.