So I have a 2001 BMW E46 330Ci. The key to the car is pretty busted and currently works with tape holding it together. So I got a new key off eBay, and had it cut so it matches. I did the whole hold unlock/lock to set up the buttons on the key, and it now works BUT it does not start the car.

I know there are transponder chips in keys which is like a little black chip which sends a radio signal to the ignition when the key is inserted which ofc my new one does not have. Seeing as my old key is busted, my thought is that i'll just move the transponder from the old to the new and job done. But I can't for the life of me see where this chip is? I've opened up the key and nothing falls out, there are a few different chips soldered to the board. Is it one of them? If so, what can I do?

Pics of the key

Ebay link for the key I got

Also posted on Reddit

1 Answer 1


So, just in case someone else has this question, thought i'd keep it up and answer it. The transponder for the E46 is soldered onto the circuit board. So, to use an aftermarket key or any other key, the process is to get the key cut, and then get it programmed as a new key. To do this either visit a car key specialist or then you can get an "AK90" kit online, which you can program a new chip onto and then put this in the new key.

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