Key won't work after RS, 04 Taurus

Put a 570T into my brothers o4 Ford Taurus. uksed the key in the box bypass, (556UW) they had a total of three keys already. Hooked up the neg keysense wire,(BLACK/ pink) and with one of the keys, my bros, the car will work fine. will start with his key. With his wifes, the key wont work at all, it used to.

maybe the system lost the programming for the keys.  i believe the way to reprogram the keys on a ford, is to start it with the key that works, then shut it off, then within a few seconds start it with the key you want to program.  someone correct me if i am wrong, but i would give that a try.

No that doesn't work. First, you don't need the BLACK/ pink keysense wire on a Ford. Just the red, black and blue wires will suffice. I don't think it would created a problem like you describe tho. The theft light will flash if it sees a non-programmed key or if it sees two keys at the same time during crank. After the car starts in really doesn't need to see a transponder key at all. To program a key, you need two working keys to start with. Insert one working key, turn to on for a few seconds and remove. Insert the second working key, turn to on for a few seconds and remove. Now insert non working key and start car with it. It's now programmed. If one working key is now in the 556U, you can substitute  turning the second key to on by remote starting the car for a brief second(or you can simply remove the key from the 556U for programming).Mike M2

Tech Manager

CS Dealer Services

the reason I hooked up the keysense wire was because after i installed the RS, i tested it and it worked fine. Then i tried to start the key a few minutes later with my brothers key and it wouldnt crank at all. hooked up keysense wire and it works. But still not sure why hers isnt working anymore. Can you have three programmed keys for the fords???

You can have 4 total...Mike M2

Tech Manager

CS Dealer Services

2000-2005 taurus can have a max of 8 keys programmed

as said by Mike that is the key programming method. what i would do is unhook the keysence wire because it is not needed and u may have tapped into the wrong wire messing it up.  take the key out of the box. go threw the programming with first the 2 keys that start the car and then the 3rd and try..

disconnect your interface. take key out of interface. Try starting up car with first key. Then check 2nd key and then 3rd key. If you started with 3 working keys you should still have 3 working keys.Street Dreams Car Club

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