Yet another key query
I know there is a lot of key information on the site, and I've read what I can find, but I don't think it covers my specific case. I recently bought a 2003 147 2.0TS from a used car dealer and it came with only one key. Contacting the previous owner, it turns out that she had an old and somewhat trashed key which I think she had lost and then found after she'd paid for a new key.
I tried it in the car and it turns the switch but reports immobiliser failure (i.e. it cranks but no start). I thought it might be the battery but when I got it open, there seems to be a little passive RF transponder which I assume is the code sensed by the car when the key is turned.
Does this mean that the transponder in this second key has a code not recognised by the immobiliser? Can that code be added to the immobiliser without the full expense of a new key? If so, how?
To further complicate matters, I'm based in Australia!
Thanks for any advice (even if it's "spend more time searching the site"!).