My Anti-Theft on my 2001 Ford Escape got messed up because I used an old key (This was the key that came with the car, it had worked fine for 5 years, then I lost it for a total of 6 months, meanwhile got a new coded key, then found the missing key and tried to start the car with it.) .
1. I tried the old key, car did not start, Theft light blinked. ,
2. Tried new key that i had been using successfully for the last 6 months. Car won't start, theft light blinks.
3. Tried various things, such as locking, unlocking, turning alarm beeping on/off, disconnecting battery, etc. Nothing works.
Called the dealer, they say they know nothing. Must bring car in, they say. Basically I am screwed and now must spend big bucks to take it the dealer because of Ford's software bug.
I went to my owners manual and followed the procedure called "Programming remote transmitters". This fixed the car. Now the new key works again, as it has worked for the last 6 months. It is a very difficult procedure to follow and we tried it 3 times before we had success.
teresa, July 2009