See also:

Problems with the SmartKey
Problem Possible causes/consequences and Solutions You cannot lock or unlock the vehicle using the SmartKey. The SmartKey battery is discharged or nearly discharged. ...

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 ...

Installing the towing eye
Vehicles with a trailer tow hitch: if possible, secure the towing device on the trailer tow hitch. – Remove the towing eye required for frontal or rear coupling from the vehicle tool kit. The ...