Seat belt pretensioner on the passenger side deployed (sounded like a shotgun blast in the cabin) without provocation. no accident, did not run over anything, etc. going straight ~45mph on an empty street at 12:50am. smoke billowing out of the cabin of my car, all the lights were on, bells were ringing, etc. it's as if i was in an accident, but no airbags deployed. frightening experience! gm said it is not their problem.