Engine Cut Off While Driving

A friends b4 shut off (like you turned the key off) setting a low voltage Air Bag code and resetting the trip odometer to zero. It immediately restarted and has ran fine since (one day). I know it initially sounds like either the ignition switch or 109 relay, but why would the trip odometer reset ? I told him to clean the grounds as well. I cleared the code and it hasnt returned.

I would concur with the cleaning the grounds. I do wonder about the 109 as well - I would be tempted to swap it out if it's original. I don't recall mine resetting the trip meter - but it only "blipped" once on the highway before swapping it out.