DESCRIPTION

This vehicle uses an antilock brake system designated MK25e. For this vehicle, MK25e is standard with Electronic Stability Program (ESP) and All-Speed Traction Control.

This antilock brake system uses components of the base brake system, but also features the following components:

• Integrated Control Unit (ICU) - Hydraulic Control Unit (HCU) (2) and Antilock Brake Module (ABM) (1)
• Wheel Speed Sensors (WSS) - Four sensors (one at each wheel)

ABS

The purpose of the antilock brake system (ABS) is to prevent wheel lockup under braking conditions on virtually any type of road surface. Antilock 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.

ELECTRONIC STABILITY PROGRAM

TRACTION CONTROL

OFF-ROAD ABS

Four-wheel-drive vehicles are equipped with Off-Road ABS. Off-Road ABS provides more sustained wheel lockup than normal ABS for improved stopping performance on plowable surfaces like loose dirt, gravel, sand and mud. Such plowable surfaces move out of the way as the tires roll on them and form a wedge in front of the tires during braking because more sustained wheel lock up causes the tires to drag and the loose surface to build up in front of the tires, helping to stop the vehicle. A vehicle with normal ABS requires a longer stopping distance on the same terrain because the wheels continue rotating, not allowing the drag and build up material in front of the tires.

ELECTRONIC STABILITY PROGRAM

ESP® (Electronic Stability Program), which includes Hydraulic Brake Assist, Traction Control, and Electronic Roll Mitigation is standard on all vehicles. ESP aids the driver in maintaining vehicle directional stability. ESP will do whatever can be done, within the limits of available traction, to keep the car on course.

ESP uses the ABS with Traction Control (MK25E) along with the following components to operate:

• Dynamics (ESP) Sensor
• Steering Angle Sensor (SAS)

HYDRAULIC BRAKE ASSIST

Brake Assist is programmed into the ESP® system. Brake assist helps the driver overcome the tendency to not apply the brakes hard enough or quick enough to achieve the minimum stopping distance during a panic stop. During this situation, the ESP® system instantly applies the maximum available pressure to the brakes and the vehicle stops as quickly as available traction will allow.

TRACTION CONTROL

ELECTRONIC ROLL MITIGATION

ESP Full-On and Partial modes include an algorithm for Electronic Roll Mitigation (ERM). ERM is an algorithm on top of ESP control that is targeted toward preventing wheel lift in the NHTSA Fish Hook maneuvers. These very extreme situations are well out of normal everyday driving, but by chance a high dynamic maneuver occurs, ERM can help return vehicle stability and control to the driver. Electronic Roll Mitigation attempts to determine when a vehicle is in a position to mitigate vehicle rollover and minimize the risk by applying the appropriate braking force to reduce the likelihood that such an event will occur. This added measure is designed to aid the driver in maintaining vehicle stability during an emergency maneuver or accident avoidance situation. ERM will not aid vehicle stability in “trip” situations, such as when a vehicle slides sideways and strikes a curb, which could then cause the side opposite the curb to lift and the vehicle to roll.

TRACTION CONTROL

The traction control system that is part of the Electronic Stability Program (ESP), is an all-speed traction control. All-Speed Traction Control enhances mobility and prevents wheel slip when accelerating on slippery surfaces. It also provides a measure of directional stability control. Using the wheel-speed sensors, it can detect excessive yaw and help keep the car on the intended course, as for instance, when accelerating around a curve.

All-Speed Traction Control is effective up to 85 mph (137 km/h).

The traction control system may be turned off or on by depressing the ESP Off switch button located on the instrument panel.