05 sport trac won't start after installing rebuilt alternator
I changed the alternator and when I reconnected the battery the anti theft
system went off. Tried to start truck but not cranking.
The vehicle may have lost it's programming not allowing the "chipped" key to be read. If the PAT (Passive Anti Theft) code is not read in the key, or doesn't match the program, the vehicle will not start. Your only shot is to try a spare key if you have one and see if that one works. If not, you will most likely need to have a Ford technician flash the ECM unfortunately.
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