what do i do the diagnostic light has come on in my car?

Diagnostic check from dealer, I believe about £50. IF you have a laptop, go on ebay get an obd reader, Varies about £10. That would connect your car to your laptop and tell you the fault code, and what it means. Might be nothing, as said could of been a glitch, but find out is advisable. You can also go to places like halfords etc, also on ebay, they do stand alone readers for about same price as you would pay a garage, So still better value, as you would then still have the reader. You would be able to reset the error code via a laptop or stand alone reader. BUT only after sorting the problem out if needed. Keep resetting an error when there is a problem, will lead to bigger problems, SO always get the problem sorted.

SD
December 2012

There is a fault registered in your ECU,it may be present or it may be a small glitch which is no longer there and the only way to find out is to plug in a code reader to determine what brought your light on,if the motor is running ok and feels normal then it is up to yourself if you carry on your journey but would think about getting it seen to a.s.a.p

cdc
December 2012