Cadillac computer

I own a 1994 Cadillac Deville with 151,000 miles on it, I recently had my transmission replaced. Ever since then I have had some problems with a few minor things such as: Fuel reads "E" all the time, I can't open the gas tank.I have to pull the pully in the trunk to open it. The lights will not go on or off automatically, the cadillac repair shop I took it to. Which is out of town says that they didn't cause it. It was all fine when it went in but not on the way out. Could it be the computer or could it need to be reset?