'Engine Fault'

Evening,

I've had the 'Engine Fault' message come up on my Dash today. No other message, just that. The car appears to drive fine.

Any thoughts (!) on what this incredibly helpful message may be?

I have an OBD2 adaptor that worked fine in my C4 (2005), but in my GP (2010 1.6 EGS) isn't working. It doesn't seem to be able to communicate with the car. Is there anything I can do to get it going so I can find what the error code may be?

Or am I out of luck and need to pay a visit to a garage?

Thanks!

Ben.