By coincidence, mine came on yesterday - 60 miles after VW main dealer had completed a fairly inept service damaging my car. I understand
there are various potential issues - lamda sensor, small hole in exhaust systems and numerous other valves/sensors.
How if you car performing? Mine seems fine except the engine sounds a little hoarse... Need to get the fault code checked to know more - except I certainly won't be using the main dealer again.
I tried tightening the petrol cap but this didn't seem to make any difference.