Had my MK6 GTI since last June and absolutely love it.
Recently the engine light came on, so looking at the manual it said "fault in the catalytic convertor" I booked it in to the garage to be told it was £100 just for them to plug it in.

anyway, the light went off a few days later and I cancelled the garage and completely forgot about it. After filling up at the petrol station when I started the engine the light came on again.
Anybody on here have any suggestions as to what this could be, and why the light went off and has came back on again?
Cheers