I had the exact same thing happen to me. The first time it happened the service 4wd system msg came up and it wouldn't turn over,but after a few tries it went. 2 weeks later same thing but this time no go, had to have it towed. the dealer said it was loose ground wire somewhere. Then this past weekend on a short trip in -25 c temps got a service def system msg and then a check engine light but truck ran fine. I normally keep it in a heated shop and when I drove it yesterday the msg was no longer displayed and after driving it for a while the check engine light also went out. sure hope this isn't a sign of things to come.