Hi, I've recently had an almost identical experience with my 2016 TDi: Air con stopped blowing cold suddenly, went to a garage in Bristol (BS3 Motors) that found the Air Quality Sensor fault code, regassed, said there were no obvious leaks then suggested replacing the sensor for about £220 including 90 mins labour. I ordered a cheap Chinese part online and fitted it myself with no tools apart from a small screwdriver in less than 10 mins. This threw up various error codes, so got a German made Hella part instead (Skoda-Parts.com were helpful and only charged the difference in price without asking for the dodgy part to be returned - you might say they shouldn't have stocked the Chinese part, but to be fair I think I knew I was taking a bit of a risk buying it!) All the error codes are now resolved, but although the fan is working away, the air is, alas, still not conditioned! I left BS3 Motors a not very complementary review. Although I think it was completely fair, and quite moderately worded, I don't suppose they would welcome me back, even if I trusted them - which of course I don't. Any suggestions of: a) anything I might be able to check myself as an incompetent DIYer? b) any garage in or around Bristol that knows what the are doing with air con?