See also:

Assembling the ball coupling
Mercedes-Benz recommends that you have the ball coupling assembled at a qualified specialist workshop. Only a qualified specialist workshop has the necessary specialist knowledge and tool ...

Important safety notes
WARNING When leaving the vehicle, always remove the SmartKey from the ignition lock. Always take the SmartKey with you and lock the vehicle. Do not leave children unattended in the vehicle ...

Restoring the factory settings
Press the and buttons simultaneously for approximately six seconds until the battery check lamp flashes twice. ...