I still need an answer if someone can find it.
I have looked on the internet and someone has posted a video on youtube showing how he solved a similar problem. However, his answer was to remove the immobiliser unit competely and then link 2 terminals on the socket which had the immobiliser plugged in.
However, I see this as a last resort and would only be attempted if I lost the one working key. To do this now may result in neither of the keys working if I get the linking wrong.It may also stop the alarm and door locking functions from working.
Do you not have an auto-electrician who has had experience with this immobiliser unit? It seems to be a standard fitment on all previas from 1990 to 2000 at least.
The solution is not urgent as I still have one working key, so you can take some time to find someone who can answer.
Please try to find someone.
I rated you excellent, but I have not tried the solution - and will not unless the working key gets lost (I am looking after it well so I may never need to bypass the immobiliser.) Perhaps you could advise me if I need to implement the solution whether I should remove the unit completely and simply link the yellow wire to the next-to-last socket as per the youtube video, or leave the unit still connected and link those 2 wires. Does the immobiliser unit also control the central locking which currently works OK using the separate wireless "clicker"?- and if I remove the unit completely will that stop the central locking from working?
I would appreciate an answer if you have one - or I will have to try with and without the unit connected if the need arises.