Replaced ecm and now no start... HELP

[Ranger lover]

I replaced the computer module in my 2001 xlt v6 3.0 auro trans, with a module out of an exact match ranger. And now when i try to start it the anti theft light flashes real fast, and no start at all. Whats wrong why wont it start? How do i sync my key to the replacement brain module? Will flashing the new brain box fix the problem? Please help...anybody...Ford dealership says ecm obsolete so they wont help. Is it possible to have a key made that syncs to the new box, that will make it work?

 

[Cemeteryxgates]

Need the key from the donor vehicle or have keys programmed through popalock or other companies but to the pats code

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[stmitch]

Your truck has Passive Anti Theft System (PATS). Theres a transponder in the key, a module in the steering column, and the PCM. They all three have to match or it won't start. A dealer can reprogram things, or an aftermarket tuner can delete the functions completely.