Panerai197

My seat belt pre-tensioner looks to have stopped working, i remember it used to nip up when when I put the seat belt on and drove off to take up the slack, should it pretension every time.

Car 2015 D4

MP4.2+6.0

Can't say beyond it does not sound normal. Yes, it should generally snug up by itself.

Try pulling belt out all the way slowly a few times and then let it retract back in fully--in case it didn't wind squarely on the take up reel or some such. Beyond that idea, see the dealer for a possible warranty issue.