I had 2 2002 f-150's. I took the cab and box off one, and swapped it onto the other frame, and complete powertrain. The first time I started the truck after the swap, it started fine, but when tried to start it again, the theft system was activated. I can't seem to find any reason why it would be in theft mode. Any ideas? In case you're wondering, one truck had a damaged frame, and the other had a damaged cab.
Thanks.
Brian

 

well if the computer doesnt reconize the ignition, and PATS key chip off of the new cab, then it would think its been hot wired. and will not turn back on.

I vote get the key/ cylinder out of the truck that had the motor originally, swap it in, and you should be good to go.
-Patrick

 

Pat, that's what I thought, (about the cylinder and key) but that didn't work.
Brian

 

The PCM and the Pats have to match because the VID needs to be read for validity.
A dealer reflash could fix this as long as you have 2 program keys that match the PATS you are useing.
Turn the ignition on and let it that way for about 2 minutes and see if the Theift lamp flashes a code. This will give you some indication of what isn't right.
A code 16 says the PATS can't talk to the PCM.

 

Thanks, Bluegrass. I do come up with a code 16. That's why I thought I could swap the key, cylinder, and the small box surrounding the cylinder, which I assume reads the chip in the key. When this didn't work, I thought I could swap the computer, but the only ones I see are in the cab, so everything should match up. I'll work on it one more evening and if I can't figure it out I'll call the dealer. Just hate to have it towed.

 

Tonight I found I had not connected the horns or the ground on the right side of the rad cradle. I connected them but the theft system was still engaged. About 1/2 an hour later the system was off. I assume it was one of the two, and the system must need a certain amount of time to reset itself.Who knows.

 

It does have a timing function.
I put an un-programmed key in and turned the engine over but no start.
Even the original key would not start the engine after that until some time out had occurred.
I assume it is a logic decision the PATS makes for protection.