Hi Johnk854, The new battery hasn't/didn't stop the light from coming on, what has happened is when you removed the old battery that cleared the fault code, then it has taken half an hour of running for the fault code to reappear. I have the engine code reading software but I am in Shropshire and I think you are way down south...maybe somewhere near you will see the thread though and offer, or if you are going by this way let me know. Rbaggers, unfortunately I have no idea with your problem and not even sure that my software would read your car...it would be interesting if you could read the software whilst on the move and grab the fault code as it shows....my software does that so if it works with Diesel I'd be happy to have a look. Let me know if I can help, Paul.