Anti-Lock Brake System

This article covers the physical and operational descriptions, and the on-car service procedures for the Mark 20e Anti-Lock Brake System (ABS) with traction control. It is the only anti-lock brake system available on this vehicle.

All vehicles equipped with ABS use electronic variable brake proportioning (EVBP) to balance front-to-rear braking when the brakes are applied in the partial braking range. For more information on electronic brake distribution, refer to ELECTRONIC VARIABLE BRAKE PROPORTIONING  .

The traction control system reduces wheel slip and maintains traction at the driving speeds below 64 km/h (40 mph) when road conditions call for traction assistance. For more information on traction control, refer to TRACTION CONTROL SYSTEM  .

This system shares most base brake hardware used on vehicles without ABS. A vehicle equipped with ABS, however, uses a different master cylinder and brake tubes. Also included in the ABS system is an integrated control unit (ICU) and four wheel speed sensors. These components are described in detail in this article. All vehicles with ABS come standard with four-wheel-disc brakes and traction control.

The anti-lock brake system prevents wheel lockup under braking conditions on virtually any type of road surface. Anti-lock braking is desirable because a vehicle that is stopped without locking the wheels retains directional stability and some steering capability. This allows the driver to retain greater control of the vehicle during braking.