Anti-Lock Brake System (ABS) Function

WARNING: This page is about a different car, the 2015 Ford C-Max. However, it is still accessible from the selected car via links, so may be relevant.

The ABS module continuously monitors brake pedal input, lateral vehicle motion and the rotational speed of each wheel. The ABS module receives the brake pedal input directly from the brake pedal travel sensor and the brake booster travel sensor while the RCM sends lateral acceleration sensor information to the ABS module over a private HS-CAN. Wheel speed information is retrieved by the ABS module using 4 wheel speed sensors. When the ABS module detects an impending wheel lock during a braking event, the ABS module modulates brake pressure to the appropriate brake caliper(s) by opening and closing the appropriate solenoid valves inside the HCU while the hydraulic pump motor is activated. Once the affected wheel(s) return to the desired speed, the ABS module returns the solenoid valves in the HCU to their normal position.

When the ABS module is initialized (ignition ON), it carries out a preliminary electrical check of the system sensors and activates the hydraulic pump motor for approximately one-half second. During this time, a buzzing or humming noise may be heard and a vibration may be felt in the brake pedal and is a normal condition. During the module initialized self-test, the pump motor check is carried out at approximately 10 km/h (6.2 mph). Any malfunction detected in the system causes the module to set a DTC, disable the ABS function and send a message over the HEV HS-CAN to the GWM. The GWM then sends a message to the IPC over the MS-CAN to illuminate the ABS warning indicator. The base hydraulic power assist braking system functions normally.