hi i have a customers fiesta mk4 diesel with an immobiliser fault i cannot turn it off it is a ghia model with an alarm with only one key have tried another transponder unit on the column and this worked for a couple weeks now wont entertain any kind of tinkering does anyone out there in ford land that knows a bypass for this system or is it a ford dealer problem. cars worth nowt and dont want to pay extortionate dealer price if i can do it myself!!!!