2003 LB7 had the juice attitude hooked up since Dec. No problems until today. Had a little trouble starting, then drove to get some fuel left the truck running as I filled up and the truck just stopped running. I started it up again, ran for 10 sec, stopped again. I disconnected the edge and tried to start it-nothing, called Onstar for diagnostic scan they said communication problems with ECM. Disconnected the batteries hoping to clear the problem. I don't want to take to the dealer, just clear code any ideas to reset? Scanned with OBD2 code reader nothing is coming up.

Thanks