Antilock Brakes / Traction Control Systems: Description and Operation

PURPOSE
The 4-Wheel Anti-Lock Brake System (4WABS) prevents wheel lockup by automatically modulating the brake pressure during an emergency stop. By preventing wheel lockup, the driver can maintain steering control and stop the vehicle in the shortest possible distance under most conditions.

CHARACTERISTICS
The 4WABS controls each brake separately. The brake pedal force required to engage the 4WABS function may vary with road surface conditions. A dry surface requires much less force.

During 4WABS operation, the driver will sense a pulsation in the brake pedal, accompanied by a slight up and down movement in the pedal height and a clicking sound. The pedal effort and pedal feel during normal breaking are similar to that of a conventional power brake system.