9-3 Coupe (9400) L4-2.0L Turbo (B204) (1999)
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Seat Belt Tensioner: Description and Operation
Seat Belt Tensioner
The car is equipped with seat-belt tensioners for the front seats. A seat-belt tensioner tightens the seat belt in the event of a collision to reduce the
forward movement of the occupant's body.
The belt tensioner on the left side (LH) is connected to pin 8 and pin 9 on the SRS control module. The belt tensioner on the right side (RH) is connected
to pin 15 and pin 45 on the same control module.
The cable carries test and detonation current from the SRS control module to the seat-belt tensioner.
The seat-belt tensioner consists of an explosive charge that is activated by the SRS control module together with the front airbags.
When the charge is ignited, the gas creates a high pressure that drives a piston in an aluminium tube. The piston is coupled to the belt roller via a steel
cable. The stroke of the piston is the maximum length that the belt strap can be rolled up (approx. 12 cm) and is dependent upon the slack in the belt.
