Antilock Brake System With Electronic Stability Control (ESC)

ELECTRONIC STABILITY CONTROL

NOTE: The Electronic Stability Control (ESC) may also be referred to as Electronic Stability Program (ESP) depending on the vehicle model year and configuration. Certain components may also reference ESP, ESC, or use the traction control symbol.

Electronic Stability Control (ESC), which includes Hydraulic Brake Assist and Traction Control aids the driver in maintaining vehicle directional stability. ESC will do whatever can be done, within the limits of available traction, to keep the car on course. Hill Start Assist (HSA) is available on some vehicles.

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

- Dynamics (ESC) Sensor
- Steering Angle Sensor (SAS)
- Brake Pressure Sensor

The Dynamics Sensor includes the Yaw Rate Sensor and the lateral Acceleration Sensor. It is mounted under the center console, which is near the center of gravity of the car for effective sensing Description and Operation.

The Steering Angle Sensor is located in the steering column Description and Operation.

The Brake Pressure Sensor is located in the Hydraulic Control Unit (HCU) and is not serviceable separate from the HCU.

The ESC default mode is Full-On with every key-on. Pressing the ESC Off button once activates what is referred to as Partial mode. In Partial mode, Traction Control is deactivated and ESC operates at a higher threshold, therefore, it will not come on as aggressively as in the Full-On mode. The system can be returned to "normal" Full-On mode by pressing and releasing the ESC Off switch. The ESC function lamp is illuminated in the cluster whenever the ESC system is turned off.

HYDRAULIC BRAKE ASSIST

Brake Assist is programmed into the ESC 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 ESC system instantly applies the maximum available pressure to the brakes and the vehicle stops as quickly as available traction will allow.

TRACTION CONTROL

For information on the All-Speed Traction Control, Description and Operation.

HILL START ASSIST

The Hill Start Assist (HSA) system is designed to assist the driver when starting a vehicle from a stop on a hill by maintaining the level of brake pressure the driver applied for a short time period after the driver takes his foot off of the brake pedal. Pressure is released as the vehicle starts to move.