See also:

Engaging the differential locks
Pull away slowly when the differential locks are activated. Function or performance tests may only be performed on a 2-axle dynamometer. If you wish to operate the vehicle on such a dynamomet ...

Locking the vehicle (mechanical key)
If the vehicle can no longer be locked with the SmartKey, use the mechanical key. Open the driver's door. Close the front-passenger door, the rear doors and the tailgate. Press the locki ...

Please bear the following in mind
At the onset of winter, have your vehicle winterproofed at a qualified specialist workshop, e.g. at an authorized Mercedes- Benz Center. Observe the notes in the "Changing a wheel" se ...