VW Caddy HVAC Sensor Fault Disrupts AC Performance

Having some experience with VAG vehicles, I encountered a similar issue with my VW Golf 2013. The symptoms were nearly identical, complete HVAC system failure with error codes appearing across displays. After thorough vehicle maintenance checks, my workshop found that the air conditioning control unit was completely defective. The initial sensor calibration tests pointed to a temperature sensor issue, but it turned out the control unit was the root cause, affecting the entire cooling system operation. The repair involved: Complete diagnostic scan, Removal of the old control unit, Installation of a new AC control unit, Full system recalibration, Refrigerant recharge Total cost was 980€, including parts and labor. The fix completely resolved the issue, and the HVAC system has worked flawlessly since. To provide more specific guidance for your case, could you share: The exact error codes showing up, Whether the blower motor still runs, If you notice any unusual sounds when trying to activate the AC, The mileage on your Caddy, When the problem first started This information would help determine if your issue matches what I experienced and could save diagnostic time at the workshop.

Just had my vehicle serviced last month at 110451km and the technician did check the HVAC system functioning. After reading your breakdown, I checked the blower motor and it does run, but makes a slight rattling noise when switched on. The error codes showing are P0532 and P0533, which apparently relate to the AC pressure sensor circuit. The issue started gradually over the past 3 weeks, first with inconsistent cooling, then complete failure. The temperature sensor theory makes sense, but your control unit experience has me wondering if I should get both components checked. My coolant level and temperature gauge readings are normal, so hopefully the engine cooling system isnt affected. Did your repair shop initially test the sensors before discovering the control unit problem?

Thanks for those details. Interesting that youre seeing P0532 and P0533 codes, I had similar codes before my control unit replacement. The rattling noise from your blower motor matches what I experienced too, which initially misled my mechanic toward a sensor issue. In my case, they did extensive sensor testing first, including checking for any coolant leak and running diagnostics on the temperature sensor and heat exchanger components. All sensors tested fine individually, but the system still wouldnt function properly. That sensor malfunction indication was actually a symptom of the failing control unit unable to process the sensor inputs correctly. The progression of your issue sounds very familiar, mine also started with inconsistent cooling before total failure. The good news is that proper vehicle maintenance helped catch this before it could cause any damage to other AC components. My suggestion would be to have them: 1. Test the control unit communication specifically 2. Verify all sensor readings while the system is running 3. Check the pressure readings when the compressor engages The complete fix cost me 980€, but catching it early might save you some money if the compressor hasnt been damaged. Getting both the sensor and control unit checked is smart, its worth the diagnostic time to identify the true cause.

Thanks for the detailed info, especially about your similar control unit experience. After comparing symptoms, I went ahead and booked my Caddy in for next week at a local VAG specialist. They quoted 120€ for full diagnostics including sensor calibration tests and control unit communication checks. The matching error codes and progression pattern of the HVAC system failure definitely point toward a similar root cause. While I hope its just a temperature sensor malfunction, Im prepared it might be the control unit given how closely my symptoms match yours, right down to that rattling blower motor noise. Really helpful to know the full repair ended up at 980€ in your case. At least I now have a reasonable idea of potential costs if it turns out to be the control unit. Will update once I get the official diagnosis and repair completed.