The seat belt pretensioner system will not deploy in rear impacts and frontal impacts if the impact is less than a certain amount.
When the belt tensioner is activated, the fuel in the tensioner cylinder is burned, and as a result, the piston moves up and eliminates the slack in the seat belt system by fixing the inertial drum with a steel cable attached to the piston. If the pretensioner has been activated, the seat belt will then lock into place and the assembly will need to be replaced.
To prevent the belt tensioner from triggering when working with the seat belt, remove the ground wire from the battery and disconnect the electrical connector from the tensioner.
Attention! If there is an accidental fall of the seat belt tensioner, it must be replaced, even if it does not have any mechanical damage. Avoid contact with the seat belt tensioner of any solvents.