sean
your discription is spot on, i run mobile diagnostics and have done for 20 years constantly researching and trying to keep up with modern technology,the times i have been called into various estabilishments after they have failed to correcty diagnose faults.when we spent time diagnosing faults correctly sometimes very simple ones these establishments then charge customers who think they have done the work so creating a false customer image of a competent establishment.i am not having a pop at any garages who do a good job but the market place is getting full of code read technician
test and dont guess.you cant fix what you dont understand.cheers mike fleet