See also:

Distance warning function (vehicleswith DISTRONIC)
This function provides a warning from a speed of approximately 20 mph(30 km/h), if: • for a period of several seconds, the distance to the vehicle in front is too short for the speed at which you ...

The windshield wipers are obstructed
Leaves or snow, for example, may be obstructing the windshield wiper movement. The wiper motor has been deactivated. - For safety reasons, you should remove the SmartKey from the ignition lock. ...

Setting a speed
WARNING Keep in mind that it may take a brief moment until the vehicle has made the necessary adjustments. Increase or decrease the set vehicle speed to a value that the prevailing road cond ...