VW Tiguan Temp Sensor Fault Disrupts AC & Cooling

Had the same sensor calibration issues on my 2010 VW Touareg TDI. The cooling system started acting up, showing incorrect temperature gauge readings and triggering error messages. The root cause was actually more complex than just a faulty sensor. The heat exchanger had developed micro-cracks, causing a minor coolant leak that affected the sensor readings. This created a chain reaction, unreliable temperature data caused the AC control unit to shut down as a protective measure. The coolant leak also made the engine control unit receive incorrect temperature data. The repair required: Complete cooling system pressure test, Replacement of the heat exchanger unit, New temperature sensors, Control unit recalibration, Full system diagnostic check This was a serious repair that took multiple days to complete properly. The system needed a thorough flush to remove any contamination from the minor leak. Without proper repair, these issues can lead to more severe engine problems down the line. Make sure to get the entire cooling system checked, not just the sensors. Temperature-related problems often indicate larger underlying issues that need addressing.

Thanks for sharing your experience with the heat exchanger repair on your Touareg. Our temperature sensor issues do sound quite similar. My Tiguan is now running perfectly after the fix, but I am curious, do you remember the total repair cost for your vehicle maintenance work? Also, has the temperature gauge been showing correct readings since the repair, or have you noticed any other cooling system quirks?

Since having the temperature sensor and heat exchanger defect fixed, my Touareg has been running flawlessly. The total repair cost came to 980€ for the complete HVAC system overhaul, including the faulty air conditioning control unit replacement. The temperature gauge now shows accurate readings, and the sensor calibration is spot-on. The coolant level has remained stable with no signs of leaks. It was worth every cent to get the cooling system properly diagnosed and repaired rather than just replacing parts hoping to fix the issue. The mechanic did a thorough job testing the entire system after the repair. Having experience with these VW cooling systems, they knew exactly where to look for the root cause. The investment in proper repair prevented what could have become a much more expensive engine problem.

Thanks for the input. Just wanted to follow up on my Tiguan repair story. After reading about similar experiences, I took it to a certified VW specialist who immediately spotted issues beyond just the temperature sensor. The mechanic found small cracks in the heat exchanger that were causing subtle coolant loss. This explained why the engine cooling system was acting up. They did a complete overhaul: Replaced the damaged heat exchanger, Installed new temperature sensors, Performed sensor calibration, Flushed the entire cooling system The repair took 2 days and cost 850€, but the results were worth it. The temperature gauge now shows accurate readings, the AC works perfectly, and all error messages are gone. Been driving for 2 months now without any sensor malfunction issues. Really glad I got a proper diagnosis instead of just replacing parts out of nowhere. The thorough inspection prevented what could have become a major engine problem.