Ok, so let me tell you what is going on, what I did and how it all went down. So a few months ago I bought a 2002 Grand Marquis LS, it had 61,000 miles on it. Changed oil to full synt, new tires, new headlights, and new wheels and cherry bomb exhaust on it (single exhaust). After the exhaust was placed on, I received an emission code, because of it... I cleared it, because I knew that it had something to do with the no back pressure on the exhaust system. Afterwards, I came in contact with a guy who bought a Jet programmer to add extra 30 hp to it. So I bought a programmer, and reprogrammed the PCM ( bad idea!!!). At one point my vehicle indicated overheating, and then stalled and shut it off.. this happened a few times.. the cooling system is fine, and all the sensors were fine. I believe it had something to do with me reprogramming the PCM... so I went ahead and reprogrammed the ECU to its original factory system... Well, the ECU still said that the car was overheating and in fact it wasn't so I played dumb and drove it to a garage, they let it run for 3 hours and as they pulled to test drive it, the car computer state it overheated... and then in the end they said I need a new ECU, because they checked the cooling system and the thermostat was opening, there was flow, no restrictions or anything. So, I am about to receive a refurbished ECU, it is programmed to my VIN number and it is the same part number... however regarding the PATS system, I have the original keys.. do THE PATS System still have to relearn the keys or am I good to go?