Anti-Lock Brake System: Operation

When ignition is turned to RUN position, the instrument cluster starts a bulb check by illuminating the ANTILOCK and BRAKE indicator lights. The bulb check ends when instrument cluster receives a class 2 serial data message from EBCM and BCM that no malfunctions were detected. If no malfunctions were detected, instrument cluster will turn off ANTILOCK indicator light after 2 seconds and BRAKE indicator light will turn off a second later. This confirms correct operation of EBCM and indicator lights. If EBCM detects a malfunction, either on power-up or during operation, it will notify the instrument cluster via the class 2 message to illuminate ANTILOCK indicator light. If malfunction affects operation of the base brakes, the BRAKE indicator light may be illuminated as well.

The ANTILOCK indicator illuminate when EBCM detects a permanent ignition or condition latched DTC, or instrument cluster cannot communicate with EBCM module using class 2 serial data communications. The BRAKE indicator light will illuminate when parking brake is not released, Dynamic Rear Proportioning (DRP) registers a critical malfunction, there is 2 or more DRP non-critical malfunctions, or brake fluid level is low.