Antilock Brakes / Traction Control Systems: Description and Operation

The Anti-lock Brake System (ABS) prevents wheel lockup by automatically modulating the brake pressure during an emergency stop. By not locking the wheels, the driver can improve steering control during hard braking and stop the vehicle in the shortest possible distance under most conditions.
The ABS controls both front and rear brakes separately. The brake pedal force required to engage the ABS function may vary with the road surface conditions. A dry surface requires a higher force, while a slippery surface requires much less force.
During the ABS operation, the driver will sense a slight pulsation in the brake pedal. In addition, a mechanical noise from the engine compartment may be heard. The pedal effort and pedal feel during normal braking are similar to that of a conventional power brake system.