Hi, just purchased a 2001 TT Quattro and the A/C is blowing very warm. I've checked the refrigerant pressures in the lines and they're okay. Also, had the compressor checked and it's apparently okay. When I run the diagnostic on the climate control system, it showed a code for the pressure (thrust) sensor (22.1 I believe). So I replaced it with a new sensor and a new code showed up 15.3 (Air Flow Flap Motor Potentiometer). According to many websites, USA and Canada vehicles do not have this part and codes should be disregarded. According to my Bentley manual, my car DOES have this part, but based on my understanding of what this does, it should not make the A/C blow extremely warm. It just controls the amount of outside air coming into the vehicle (ie. the econ and recirc modes). I have not bothered to try and replace this part, yet, as I have not found much info on it online or a DIY of how to do it. Nor is it covered in the Bentley manual. Any other ideas what could be the problem? My mechanic said it could be some sort of air blend valve or some other switch, since the refrigerant levels were good and the compressor was kickin on an equalizing properly. He could not, however, provide a diagnosis and he's stopped returning my phone calls (which tells me he's stumped). In any case, please help a noob out with any useful insights! Thanks!

 

Hmm, Is it making any weird noises when depressurizing? (turning it off)
Mine did that, it wasn't working right, and had to find out myself what was wrong, because the dealer mechanics are challenged in more ways than one.
Turned out it was the expansion valve that was bad.

 

Nope...no weird noises. Everything sound as it should and the fans are blowing plenty, just plenty of warm air! The main ECU is not showing any codes, only the self diagnostic function on the Climate control system....