Audi S1 AC Dead: Compressor Failure Warning Signs

Had a similar issue with my Audi A1 (2016) last summer. Have some experience working on cars but auto AC repair requires special tools and expertise. The symptoms you describe match what I experienced, complete AC failure, warning light, and error codes. Initially thought it was the AC compressor too, but it turned out to be the control unit that manages the entire car air conditioning system. The repair process involved: Diagnostic scan to confirm control unit failure, Removal of dashboard components to access the unit, Installation of new control unit, System recalibration, Full cooling system test Total cost was 980 Euro including parts and labor. The automotive cooling system needed to be properly evacuated and recharged as part of the repair. Before suggesting specific solutions, could you share: What error codes are you getting? Does the blower motor still work? Have you noticed any unusual sounds before the system failed? When was your last AC service? This info would help determine if your issue is similar to what I experienced or if its something else in the cooling system that needs attention.

Thanks for the input. My car is indeed still at 189384KM since the last service 2 months ago. The error codes P0645 and P0646 show up on the scan. The blower motor works fine and pushes air, just not cold. No strange sounds noticed before failure. The auto AC repair quotes I received range from 850 Euro-1200 Euro just for parts, which seems high even for a vehicle HVAC system repair. The workshops say they need to check for a refrigerant leak first before confirming if its the compressor. They also mentioned the need for a new dryer unit when doing AC unit issues repairs. Good point about checking the control module first. Will have them inspect that before replacing any major components.

Thanks for providing those details. Your error codes P0645/P0646 actually point to an AC compressor clutch circuit issue, which is different from the control unit problem I had. Based on my experience with the A1, this could still be resolved without a full compressor replacement. The lack of strange noises is actually a good sign. When my compressor failed completely, it made awful grinding sounds before dying. A clutch circuit problem often means the compressor itself is fine but just not engaging. The repair should include: Testing the clutch relay and wiring, Checking clutch coil resistance, Pressure testing for refrigerant leak, Possible clutch assembly replacement if worn If they do find a refrigerant leak, the dryer replacement is mandatory since the cooling system will be opened. My shop charged around 180 Euro just for the dryer plus labor. The automotive cooling system in these models is generally reliable, but the clutch circuit can be a weak point. Make sure they check the electrical components before committing to a full compressor replacement. Worth mentioning that when I had the vehicle HVAC system serviced later, they found the original diagnosis saved me from an unnecessary full compressor replacement.

The P0645/P0646 codes helped narrow things down a lot. From what Ive read about similar auto AC repair cases and based on my cars symptoms, the clutch circuit diagnosis makes more sense than a full compressor replacement. Will ask the shop to specifically check the clutch components and wiring before doing any major work on the cooling system. If they do find a refrigerant leak during testing, I understand now why the dryer needs replacement, seems to be standard practice when opening up the vehicle HVAC system. Really relieved it might just be an electrical issue rather than needing a whole new AC compressor. The diagnostic approach could save me hundreds in unnecessary parts and labor. Will update once I get it checked and know more about the actual problem with the auto refrigerant system. The price range makes more sense now too, looks like 850 Euro-1200 Euro would be on the high end if its just the clutch circuit. Going to get a revised quote focusing on that first before considering full replacement. Thanks for sharing your experience and helping me understand the repair process better.