Normal Operation
During moderate to heavy braking, noise from the hydraulic control unit (HCU) and pulsation in the brake pedal can be observed. Pedal pulsation coupled with noise during heavy braking or on loose gravel, bumps, wet or snowy surfaces is acceptable and indicates correct ABS function. Pedal pulsation alone or steering wheel nibble when the brakes are applied (frequency is proportional to the vehicle speed) indicates a concern with a brake or suspension component.