The tensioner is triggered by a frontal impact when the collision force exceeds a certain value. For weaker impacts and impacts to the rear of the vehicle, the system does not work.
Once the fuse is triggered, a small capsule instantly releases gas, filling the tensioner cylinder. The piston in the cylinder moves along the cylinder, pulling the cable, thereby tightening the seat belt. After the seat belt tensioner is triggered, it is replaced along with the impact sensors.
There is a risk of injury due to unauthorized activation of the system during work in the car interior. It is recommended to entrust work requiring intervention in the system to specialists of the dealer car service. Please pay attention to the following warnings before deciding to carry out such work yourself.
Attention!
- Do not expose the pretensioners to temperatures exceeding 100°C.
- Always disconnect the battery ground cable when working on seat belt systems (see warnings in chapter 12, concerning SRS systems).
- If any work on the car requires sledgehammer blows (sometimes a hammer is enough), remove the pretensioner control system fuse, de-energize the system, and wait at least five minutes for the system to deactivate.
- If the tensioner mechanism has been dropped, it must be replaced, even if there is no visible damage.
- Do not allow any solvents to enter the tensioner mechanism.
- Do not attempt to open the tensioner mechanism - it contains explosive gas.
- The tensioners must be discharged before storage, but this operation should be entrusted to specialists at the dealership service center.