See also:

Lane Keeping Assist
Important safety notes Lane Keeping Assist monitors the area in front of your vehicle by means of a camera at the top of the windshield. Lane Keeping Assist detects lane markings on the road an ...

Mercedes-Benz M-Class Owners Manual
...

Cleaning the display
  Before cleaning the display, make sure that it is switched off and has cooled down.   Clean the display surface using a commercially-available microfiber cloth and TFT/LCD display c ...