The concept

The system is functional at speeds beginning at approx. 20 mph/30 km/h.

It maintains the speed that was set using the control elements on the steering wheel.

The system brakes on downhill gradients if engine braking action is insufficient.

Do not use the system if unfavorable conditions Unfavorable conditions
Do not use the system if unfavorable conditions make it impossible to drive at a constant speed, for instance:

▷ On curvy roads.
▷ In heavy traffic.
▷ On slippery roads, in fog, snow or rain, or on a loose road surface.

Otherwise, you could lose control of the vehicle and cause an accident.◀

    See also:

    Weights
    The values preceding the slash apply to vehicles with manual transmission; the values following the slash apply to vehicles with automatic transmission. ...

    Closing the windows and glass sunroof/panoramic glass sunroof
    Driving with the glass sunroof/panoramic glass sunroof and windows open results in increased air resistance and raises fuel consumption. ...

    Malfunction
    A Check Control message is displayed. On the Control Display, the areas in front of and behind the vehicle are shaded. PDC has failed. Have the system checked. To ensure full operability: ` ...