See also:

Trailer towing
PARKTRONIC is deactivated for the rear area when you establish an electrical connection between your vehicle and a trailer. Fold in the ball coupling if the trailer tow hitch is not required. ...

Removing the towing eye
  Loosen the towing eye and unscrew it.   Attach cover 1 to the bumper and press until it engages.   Place the towing eye in the vehicle tool kit. ...

Checking the coolant level
Only check the coolant level when the vehicle is on a level surface and the engine has cooled down. Turn the SmartKey to position 2 in the ignition lock. On vehicles with KEYLESS-GO, press the ...