Fastening and adjusting seat belts
If the seat belt is pulled quickly or sharply, the seat belt retractor locks. The seat belt strap cannot be pulled out any further.
Always engage seat belt tongue 
of the seat belt into seat belt buckle 
of the corresponding seat.
of the seat belt into seat belt buckle of the corresponding seat. To adjust the seat belt height:
press button 
on the seat belt outlet and slide the seat belt outlet to the desired position. To engage the seat belt outlet:
release button and ensure that the seat belt outlet engages. Only a seat belt which is worn correctly can provide the intended level of protection. Observe the notes on fastening the seatbelt More.
NOTE Deployment of components of the restraint system when the front passenger seat is unoccupied and a seat belt is buckled
When the front passenger seat is unoccupied and the seat belt tongue of the seat belt is engaged in the seat belt buckle, components of the restraint system may deploy unnecessarily on the front passenger side, e.g. the seat belt tensioner.
Only buckle the seat belts as intended.