If the seat belt is pulled quickly or sharply, the seat belt retractor locks. The seat belt strap cannot be pulled out any further.
of the seat belt into seat belt buckle 
of the corresponding seat. Vehicles with PRE-SAFE®: if the front seat belt is not pulled tight across your body, the seat belt adjustment may automatically apply a certain tightening force. Do not hold the seat belt tightly while it is adjusting. You can activate and deactivate the seat belt adjustment function using the multimedia system.
Vehicles with automatic front passenger front airbag deactivation system:
If the seat belt tongue is engaged in the seat belt buckle of the unoccupied front passenger seat, the seat belt tensioner and the side impact airbag may also deploy in the event of an accident along with other systems.
Vehicles without automatic front passenger front airbag deactivation system:
If the seat belt tongue is engaged in the seat belt buckle of the unoccupied front passenger seat, the seat belt tensioner may also deploy in the event of an accident along with other systems.