Transponder in ignition key?

[fopetesl]

56 reg Aygo. Really pleased with it even though after only 120K miles it drinks engine oil.

My remote unlock key fob was falling apart so I bought a 'service' kit off' eBay.

Rebuilt easily, or so I thought.      Now although the lock/unlock remote works fine I cannot start the engine. Cranks over but never fires up.

With the spare key without remote unlock it starts fine.

So. Do the keys have a transponder?  If so I now have a faulty key fob.

 

 

[fordulike]

If it's anything like my old Micra keyfob, it will have a tiny passive transponder in the body of the fob. It was a little green thing IIRC.

You might be able to fish the transponder out of the old fob and put it in the new one, but don't quote me.

[fopetesl]

Gotcha! fordulike. Nice tip 😁 Many thanks.

I dug out the old fob and sure enough buried in a corner is a small black block. Clearly a transponder.

Fitted into new key fob and Bingo! Works fine.