See also:

Removing a wheel
Unscrew the wheel bolts. Do not place wheel bolts in sand or on a dirty surface. The bolt and wheel hub threads could otherwise be damaged when you screw them in. Remove the wheel. ...

4MATIC (permanent four-wheel drive)
4MATIC ensures that all four wheels are permanently driven. Together with ESP® and ETS, it improves the traction of your vehicle whenever a drive wheel spins due to insufficient grip. WARNIN ...

General notes
WARNING If the vehicle becomes trapped in snow, ensure that snow is kept away from the exhaust pipe and from around the vehicle as long as the engine is running. Otherwise, poisonous carbon ...