VW Up AC System Failure: Compressor Issues Explained

Having some experience with VW models, I encountered a very similar issue with my VW Polo 1.0 TSI (2013). Initially, I also thought it was the compressor, but after a proper car air conditioning diagnosis, it turned out to be a faulty AC control unit. The symptoms were identical, no cooling, system not engaging, and warning lights. The workshop first performed a refrigerant leak test to rule out low refrigerant levels. They then did a complete electrical diagnosis which revealed the control unit was the actual problem, not the compressor. The total repair cost was 980€, including: Diagnostic testing, Control unit replacement, System recharge, Labor costs After the repair, the cooling system worked flawlessly again. The workshop advised regular AC maintenance to prevent similar issues in the future. To provide more specific guidance for your case, could you share: Has the AC system been serviced recently? Does the fan still blow air (just not cold)? Are there any unusual noises when trying to engage the AC? Have you noticed any refrigerant leaks under the car? These details would help determine if your issue matches what I experienced or if it might be something different.

Last service was at 39000km and included an AC check which was fine. The fan does blow air but not cold, and no unusual sounds when pressing the AC button. No visible leaks underneath. Since my initial post, I had the system diagnosed and the workshop confirmed low refrigerant pressure through testing. Their vehicle HVAC inspection revealed a major refrigerant leak at the condenser connection points, likely due to deteriorated seals. Appreciate the shared experience with the control unit, but looks like my AC unit issues are more basic. Going ahead with the repair next week.

Thanks for the update on your VW Up cooling system situation. Interesting how our AC problems had different root causes despite similar symptoms. While my Polo needed a control unit replacement, your refrigerant leak diagnosis makes perfect sense with those symptoms. Deteriorated seals at condenser connection points are actually a common auto AC repair issue. The repair should be more straightforward and less costly than my control unit replacement. A proper seal replacement and system recharge typically runs between 200-400€, depending on the amount of refrigerant needed. Based on my post-repair experience, you might want to ask the workshop about: Using upgraded seal materials that last longer, Checking all other connection points while the system is open, Performing a UV dye test after the repair to confirm no other leaks Since your last service showed the air conditioning was fine, this kind of leak often develops gradually. Regular checks of the cooling system can catch these issues before they lead to complete AC failure. After my control unit repair, I now get the AC inspected annually, which helps spot potential problems early. Keep us updated on how the repair goes. Always helpful to know what fixes work for specific VW models.

Thank you everyone for the input. The workshop completed the repair today and fixed exactly what they found during diagnosis, the leaking condenser seals. Total cost came to 290€ including new seals, refrigerant recharge, and labor. The AC compressor kicks in properly now and the cooling system is working great again. For anyone searching with similar automotive cooling issues on these VW models, while my problem was a basic refrigerant leak, the previous responses show it could also be control unit related. Getting proper diagnosis through a workshop saves time versus guessing. Also learned these seals are a common wear item in the car air conditioning system that need periodic inspection. Will definitely follow the advice about annual AC checks going forward. Much cheaper than waiting for complete failure. Good to have this sorted before summer hits. Marking this as resolved since the repair successfully fixed all symptoms mentioned in my initial post.