Hi Chris, i have to admit to you that i havent got the foggiest of what you said there! I only know how to reset the service light, any thing else is over my head.I would be from the old school of TDC and strobe light guns.My idea of engine tuning was to advance the timing by turning the distributor on a MK2 escort !! :-) Nevertheless i would appreciate someone explaining how to read codes. Many thanks, GerC