key code.

Can anybody tell me how the key chip or security module works?

I've just got my new key which was copied from a photo. when it arrived it was cut ok but no chip. I got a new chip and put it into the key so it should work.

What I need to know is; does the security module send a code to the key chip, or does the key chip send to the module. As the key was ok for fitting in the loch and ignition I would imagine that the chip sends a code to the module. Is that correct?

Gone are the days when you could get replacement ignition keys off the shelf.

I remember when I had my first Jag, a 3.4 mk1 1957 vintage I needed a spare and bought it from a bicycle shop.