Key Coding Trouble

[EvilDonut]

Hi,
I recently changed the battery in my keyfob as it seemed it was starting to die because it took a lot of pressing to lock/unlock. After the change it was even worse, so I've put it down to the fact its a 10 year old fob and has been semi-eaten by a previous owner's dog. So I went to my ford dealer and bought a replacement keyfob (just the actual RF unit, not the key itself). I managed to code this in to the central locking system with no problems.

However, I cannot start the engine with this new key! I first tried removing the old RF unit and attaching the new one to the key. This allowed me to code the fob in, but not to start the engine. When I swap back to the old RF unit, the engine starts fine.

I'm a bit of a newbie when it comes to key coding, but from what I can tell there are TWO codes I need to get right - the central locking code (which works) and the ignition/immobiliser code (doesn't work!). I followed my manual's instructions for coding a new key, but it didn't work. The instructions are:

Insert first key (I used a manual spare key with no buttons) and turn to II. Remove. (<5 secs)
Insert second key (I used my main key with OLD RF unit attached) and turn to II. Remove. (<5 secs)
Insert new key (I used my main key again, but quickly transferred the NEW RF unit to it) and turn to II. Remove (<10 secs)
Wait 5 secs, re-insert new key and start engine. (This bit doesn't work! Control light next to clock flashes, as it does when incorrect key inserted)

My current solution is to use the main key with OLD RF unit attached, and have the NEW RF unit on the same keyring for opening/closing doors and use the key to start the engine. I don't like this as I want to just carry one key!

Does anyone know how I can solve my problem without having to take it to a ford dealer for a coding, which will probably cost 80 quid or so?

Thanks!
James

 

[Peter]

Split the keys open and swap over the little red chip inside the old key into the new key

 

[EvilDonut]

ahh ok - if I do that do I have a time limit? When you split it the battery is disconnected from the main unit, and doesn't that break it after 15 secs or something?

 

[Peter]

You might need to reprogram the keys to lock and unlock the car, but that's not a problem.

 

[red]

Indeed, there's no time limit to swap the PATs chip as far as i'm aware.

 

[EvilDonut]

I've not managed to swap them yet, because the PAT transponders appear to be sealed units within the fobs and I don't really wanna knife into them. But I've noticed another problem that may explain why I cannot code this key to my immobiliser - the transponders appear to be physically different! The old one looks (on the outside of the fob) like an infrared LED partially encased in a bit of rubber (but on closer inspection it is not an LED, it is just a bit of transparent plastic). The new one does not have this bit - instead it has a black-plastic little protrusion that looks like an actual microchip.

I'm guessing Ford's gave me the wrong type of keyfob, awesome! Hopefully I can find my receipt to return it and get the correct one. Thanks for all the help guys, will post another reply if I still can't get it working.

 

[Peter]

So precisely what keys do you have?

 

[EvilDonut]

Problem solved - I went to Ford and got the first keyfob they gave me exchanged for the correct one. When I showed it to the guy today, he couldn't understand why the first guy had given me that one, as it wasn't even compatible with my car.

Coding worked first time on the new one - the old one's ignition transponder chip mustn't have been compatible.

Thanks for the help

 

[red]

There's two types, blue and red. Maybe they gave you a blue one. This wouldn't work but akaik there are some keys for newer Fords the same shape with blue PATs.