Hill Descent Control
Hill Descent Control (HDC) included on vehicles equipped with the Off-Road Group (sales code AWL) works automatically once the vehicle is in the Off-Road Mode and the transaxle selector is in Low or Reverse. A green icon will illuminate on the instrument cluster indicating that the HDC is operating. Should a driver decide to back down a hill, HDC will back the vehicle down at a controlled rate of speed. The system determines when the vehicle is on a grade or level terrain by input from the acceleration sensor located in the Dynamics Module. Grade Sensing logic built into it activates the brakes only when descending a hill; the driver does not need to turn it on or off.
As the vehicle crests a hill, the brakes will automatically begin to pulsate and adjust the brake pressure to maintain the vehicle at a set speed of 3 mph (5 km/h.) The vehicle speed can be lowered by applying the brake or raised by applying the accelerator pedal to provide a safe descent down a hill. Once the driver releases the brake or the throttle, vehicle speed will ramp up or down to the Hill Descent Control limit speed.