Antilock Brakes / Traction Control Systems: Description and Operation

The Anti-Lock Braking System (ABS) prevents wheels from locking up when braking, regardless of the surface conditions. This allows the vehicle to stop in a shorter distance, and allows the driver to maintain directional control of the vehicle during heavy braking.
During normal braking conditions, the ABS operates like a conventional diagonally split hydraulic power assist system. During heavy braking, however, each wheel's braking pressure is modulated according to its speed. To maintain stability, both rear wheels receive the same signal.