I am new to this kind of thing! I recently purchased a Focus Zetec TDCI and last week the system engine light came on and off and would slip into limp mode. It was run on diagnostics and a code come up for the Glow Plug Relay, this was purchased from ford (had to go back as wrong part was given to me) and I have now fitted it. I cleared codes with the help of a friends OBI diagnostics machine and blow me the next day the system engine light has come up and its going into limp mode again! Are these Focus's sensitive and you need on Fords diagnostics to clear down the code? Any comments would be useful (just got rid of a Zafira with EML and no codes that cost me a fortune!)