Smart Key functions

See also:

Servicing the brakes
If the red brake warning lamp lights up in the instrument cluster and you hear a warning tone while the engine is running, the brake fluid level may be too low. Observe additional warning me ...

Cleaning the steering wheel and gear or selector lever
  Thoroughly wipe with a damp cloth or use leather care agents that have been recommended and approved by Mercedes- Benz. ...

Driving on sand
WARNING Do not reduce the tire inflation pressure before driving through sand. However, if you do so, remember to correct the tire inflation pressure before continuing your trip. Driving wit ...