Each front seat belt buckle has a pretensioner. When the car detects a wreck, the seat belt buckles also deploy, and tighten up.
If you look at the seat belt buckle, it has a area that resembles a acccordian. This area will snug up in a deployment. The seat belt buckles need to be replaced after a deployment.
That being said. There is a connector very near the seat belt buckle that connects it to the air bag system. The connector can often get dirty or loose. I suspect if you check this connector it will fix the car.
Logan Diagnostic LLC
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