iLikeEggs
Potato!
This morning I got the "Engine hot/turned off AC" message and the fans were screaming. There was no overheating and no CEL. This happened to me a while back. Turned out it was a bad connector on the pig tail to the engine coolant temp sensor. I replaced it along with the sensor and it fixed it, until now. Both parts were Duralast. I happened to have a spare pig tail and an AC Delco CTS so I replaced them. I also cleaned the negative terminals on both batteries and pulled the ECM fuse for about a minute. Started up and problem solved. Winning....for now anyway.