Hi Peter, Thanks for advising John that he can get information from www.jagrepair.com a very good resource for technical info. I would suggest that John goes to the page www.jagrepair.com/JaguarStypeElectricalOBD11Codes.htm and then scrolls down to S-type 2002.5 - 2008 FSM Workshop Manual click on that and you download a large file that gives you a full manual for the car, it is a very useful document, it contains everything you need, except a mechanic to do it for you!!!. Cheers, Graham. (I am also a retired old git in the West Midlands with a 2007 Diesel S-Type, plus a few other Jaguars) :)