First read and observe the introductory information
and safety warnings
Seat belts may become damaged during any work on the belt tensioners or while removing or refitting any vehicle parts in conjunction with any other repair work. This damage will not always be noticeable. The consequence may be that the belt tensioners could function incorrectly, or not function at all, in the event of an accident.
Regulations must be observed to ensure that the effectiveness of the belt tensioner is not reduced and that removed parts do not cause any injuries or environmental pollution. Qualified workshops are familiar with these requirements.

WARNING
The airbag modules and belt tensioners may contain perchlorate. Please comply with legislation regarding disposal.
Automatic belt
retractor, belt tensioner, belt tension limiter
Airbag systemRound Connector Systems
Note
If necessary, housing securing mechanisms (secondary locks)
must be released or removed using specified tool before
releasing the contacts. Refer to
→ Chapter „Secondary Lock“.
...
Tires, Dismounting, Run-Flat Tires and Ultra High Performance Tires
Only trained personnel can perform the assembly work on
run-flat tires and ultra high performance tires.
If equipped check the tire pressure monitoring sensor with
the vehicle diagnostic tester and if necessary replace.
...
Removing the ball coupling
First read and observe the introductory information
and safety warnings
Unhitch the trailer .
Remove the cover from the lock on the handwheel.
Insert the key ⑧ into the lock and turn it clockwise.
Hold the ball coupling tightly in your left hand .
Use your right ha ...