So I unhooked the negative battery terminal while I was changing the oil over the weekend. I finished my tasks and hooked the negative terminal back up. I left the keys in the ignition (which is something i don't typically do) but when I went to start it back up it wouldn't start. Just crank and crank with no spark, three times it actually started and immediately died. It is no giving me no function with the key (trunk, unlock, lock all disabled) and throwing code P0513. I know this code is for the SKIM key being incorrect but I cannot figure out for the life of me how this would have happened. My wife has also misplaced the other set of keys so we are stuck with a car in "theft" mode. Is their anyway besides taking/towing the car to the dealership to get this to cleared and reset. I am very mechanically minded and have worked on electronics before but I don't know what would have caused this. Not sure if it the SKIM module in the dash or if it fried the PCM or what? Any help on this issue would be much appreciated. And yes I did change the battery in the key fob just to make sure.