car immobilized by key cock up

[parts]

2001 A6 Avant 2.5 d

My key fob was at the point of falling apart when in the ignition. So I took action.

I bought a new case, I transferred the blade to the new front end OK. but I got cold feet on removing the transmitter, So I fitted the new front to the old back half housing the transmitter and batteries. This was a good physical fit

The doors open with the remote but the car won't start showing an immobilizer error .

I assumed the immobilizer was on a chip on the transmitter board and the key would work OK.

I clearly got it wrong but where ??

Help would be much appreciated especially as I have no spare

Chris

[shark_90]

The immobiliser chip is a black glass bulb in the top part of the key not the remote. You need to transfer that across to your new casing.

[parts]

Thanks ,

I have fob in pieces and can't find anything that looks like black glass ? can you give me any more info ?

Parts

[shark_90]

There is a little black glass bulb glued in to the top portion of the key next to the flip mechanism

[parts]

Thanks for that found it no probs.

One more if I may . If I re-program an old key , using the new key in the lock an existing one in the ignition method .Will the immobilizer be updated as well as the remote codes .

Parts

[shark_90]

You cannot code keys to the immobiliser without a dealer level diagnostics system