See also:

Warranty
The Service and Warranty Information booklet contains detailed information about the warranties covering your vehicle. Your authorized Mercedes-Benz Center will exchange or repair any defective ...

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. ...

Low outside temperatures
DEF freezes at a temperature of approximately 12 °F (–11 °C). The vehicle is equipped with a DEF preheating system when it leaves the factory. Winter operation is therefore also guaranteed at ...