See also:

Important safety notes
WARNING   The PARKTRONIC is a supplemental system. It is not intended to, nor does it replace, the need for extreme care. The responsibility during parking and other critical maneuvers ...

Removing the ball coupling
Observe the manufacturer's installation instructions. Press the protective cap into the ball coupling recess. Make sure that the protective cap is firmly in place. ...

Maximum permissible tire pressure
Maximum permissible tire pressure for one tire. ...