Seat Belt Pretensioner and Its Protection

The seat belt pretensioner keeps the seat belt snug against the body of the driver and passenger in a frontal collision. The pretensioner is installed in the front seats. It is activated by the airbag/seat belt electronic control unit. Depending on the severity of the collision, the unit activates only the pretensioner or additionally the airbag.

The control unit ignites a small charge in the pretensioner. The gases produced by the explosion move the piston forward in the pretensioner tube, which is connected by a cable to the belt buckle. The buckle moves downward. As a result, the free play of the shoulder and lap belts is reduced.

Illumination of the airbag/seat belt warning lamp indicates that the seat belt pretensioner has deployed. After the seat belt pretensioner has deployed, the belt works as if there were no pretensioner.

The seat belt pretensioner requires no maintenance. After deployment, it must be replaced as a complete assembly.

* Before disposing of an undeployed pretensioner, it must be forced to deploy while installed in the vehicle (dealer service).

* To prevent accidental deployment of the seat belt pretensioner and airbag, observe the safety precautions.

Securing the Seat Belt Pretensioner

PROCEDURE

1. Remove the front seat.
2. Manual seat adjustment: Secure the seat belt pretensioner. To do this, turn the latch 90° counterclockwise (perpendicular to the seat surface) and disconnect the cable (2) and drive lever from the support.

3. Power seat adjustment: Secure the seat belt pretensioner. To do this, turn the screw (2) so that the green marking in the inspection window (3) changes to red. 1 - drive cable.

* The system is armed if the cable is connected to the seat and the green marking is visible in the inspection window.