Antilock System Operation
DESCRIPTIONThe function of the Anti-Lock Brake System (ABS) is to minimize wheel lock-up during heavy braking on most road surfaces. The system performs this function by monitoring wheel speed and controlling the brake fluid pressure to each front wheel and both rear wheels during braking. This allows the driver to retain directional stability and better steering capability.
The Brake Pressure Modulator (BPM) valve regulates brake fluid pressure based on road conditions as interpreted by the Electronic Brake and Traction Control Module (EBTCM)/Electronic Brake Control Module (EBCM), regardless of master cylinder output pressure. The BPM valve can maintain, reduce or increase brake fluid pressure to the brake calipers under ABS conditions, but it cannot increase pressure above that applied from the master cylinder. However, during Traction Control System (TCS) operation, the BPM valve can apply to the front brake calipers if the EBTCM/EBCM requires that a wheel be slowed or regulated.