Same just happened to me Saturday morning. Fob didn't work got spare fob same deal, opened door with key and alarm wents nuts! tried to start but engine shut down. Disconnected battery and got the little surprise of the separate alarm battery!!!!! Anyway after reconnecting everything seemed to return to normal. Should I live in fear of repeat session? ( It's wife's car)..... PS new battery installed 2 months ago.

Any wisdom from the group would be greatly appreciated

Joe Lonardo