RS5 HVAC Failure: Heat Exchanger Sensor Alert

Recently dealt with a similar heat exchanger sensor malfunction on a 2019 S5. The symptoms matched exactly, AC failed completely and the temperature gauge showed inconsistent readings. The root cause was a faulty temperature sensor connection at the heat exchanger unit. The cooling system diagnostics indicated sensor calibration errors. After inspection, the main control unit was corroded due to moisture buildup near the evaporator. The fix required: Full diagnostic scan, Removal of the temperature sensor assembly, Replacement of the main HVAC control module, Recalibration of the engine cooling system sensors This was a significant repair requiring specialized diagnostic equipment. The entire job took about 6 hours at the shop. The issue was serious enough that continuing to drive with the malfunctioning sensor could have led to potential engine cooling problems. Recommend having it checked soon, as these sensor issues typically dont resolve themselves and can affect other cooling system components if left unaddressed. Make sure to get a detailed diagnostic report before authorizing repairs. When choosing a shop, verify they have experience with modern Audi cooling systems and the proper diagnostic tools for sensor calibration work.

Appreciate the detailed breakdown of the repair. Having gone through nearly identical sensor issues with my RS5 last summer, the diagnosis and fix process sounds spot on. The vehicle maintenance steps you outlined match my experience perfectly. The cooling system problems started showing similar symptoms, AC failure and wonky temperature readings. My repair also required sensor replacement and recalibration of the engine cooling components. Did you keep track of the total cost for yours? Wondering if prices have changed since I had mine done. Also curious if youve had any other sensor malfunction issues pop up since the repair? Mine has been running perfectly, but always good to know what to watch for.

Had the same repair done last month, the temperature sensor heat exchanger was indeed defective and needed complete replacement. The sensor malfunction was fixed along with corrosion damage around the control unit. The total came to 980 Euro for replacing the air conditioning control unit. The vehicle maintenance service included full diagnostics and recalibration of the engine cooling system. Shop time was roughly 5 hours. Since the repair, the cooling system has performed flawlessly. No error codes or temperature sensor issues have returned. The AC now maintains consistent temperature and the gauge readings are stable. Regular monitoring shows all cooling components are functioning normally. Worth mentioning the shop found moisture accumulation had contributed to the original sensor failure. Making sure the drain tubes stay clear helps prevent similar issues from developing in these units.

Finally got the repair sorted at my trusted shop. The coolant leak turned out to be exactly what was described, faulty heat exchanger sensor with corrosion damage. Paid 890 Euro all in, which included the full diagnostic scan, new sensor unit, and HVAC system recalibration. The vehicle maintenance process took about 4 hours. Mechanic showed me the corroded parts and explained how moisture buildup near the evaporator caused the sensor malfunction. Pretty much matched what everyone here described. Been driving for two weeks now with zero issues. Engine cooling system is working perfectly, AC blows cold, and no more error messages. Definitely glad I got it fixed before summer, shop mentioned these problems tend to get worse in hot weather. Thanks for all the input. Really helped knowing what to expect and made me feel more confident about the repair cost being fair.