Transponder synch to ignition key?
My 2003 BMW 325i has a rebuilt title. Since I bought it a couple years ago, it has generally been fine, with no evidence of ever being rebuilt, except a good mechanic had to do some rewiring to correct the outside temperature sensor. He said although I live in Florida, the car thought I was in Alaska. That's why my A/C kept failing when it rained and the windows got all foggy. Anyway, that's not a problem anymore. But here's the real kicker. I have always had only one key for this car and I have been worried that if I ever lose that key I'd be out of luck. So I went on Ebay and got a programmable replacement key. It turns out the replacement key could be programmed to lock and unlock doors and trunk, etc. However, it was a blank key and had to be cut. Car Max said they could do it, and did cut the key, but said they could not get it to start the car. They did not charge me anything (good guys). So I went to the BMW dealer and they could not program it either. Here's the kicker: they said that my key did not match the vehicle ID. Somehow, in the past someone had changed the key and related communication with the engine from another vehicle. The BMW dealer just said "don't ever lose that key" otherwise I could never get the car to start again. They also did not charge me for their efforts. It seems strange to me that someone with a little computer/electronics savvy could not get a new key to work with this car. Is it true that it is impossible to program a replacement key to work with my transponder even though it is not the one that originally transponder with this car? By the way, that's the best I can describe the situation as explained to me by the dealer, and I'm still not sure if I am explaining it right. Thanks for any advice.