Crafter AC Failure Linked to Faulty Temp Sensor

Experienced the same temperature sensor malfunction on my 2015 VW Transporter TDI. The symptoms matched exactly, engine cooling warnings appearing out of nowhere and air conditioning system shutting down. The vehicle maintenance revealed multiple issues in the cooling system. Initially, the diagnostic suggested a faulty temperature sensor, but further inspection showed the heat exchanger sensor was sending incorrect signals to the control unit. The sensor calibration was completely off, causing the system to misread actual temperatures. During repair, we found the main control unit had deteriorated due to heat exposure. This explained why the temperature gauge readings were inconsistent. The technician installed a new control module and recalibrated all cooling system sensors. This turned out to be a serious issue requiring immediate attention, as incorrect temperature readings could lead to engine cooling problems and potential engine damage. The repair involved replacing both the control unit and associated sensors, plus a complete system diagnostic afterward to ensure proper function. Since the fix, all cooling and AC functions have worked perfectly. Would recommend getting this checked soon, as these symptoms typically indicate a failing control unit rather than just a sensor issue.

Thanks for sharing your experience. I ran into similar problems with my 2013 Crafter about 8 months ago. The temperature gauge was showing unusual readings and the coolant leak warning kept popping up even though there were no visible leaks. After a thorough check, they found the heat exchanger sensor was damaged and the wiring harness had some corrosion. The repair involved replacing the sensor assembly and rewiring part of the cooling system monitoring circuit. Can you share roughly how much the repair cost in your case? Mine was around 780€ total including parts and labor. Also curious if youve had any recurring temperature sensor issues since the fix?

After getting the repairs done for my Transporter TDI, the HVAC system has worked flawlessly. The temperature sensor heat exchanger was indeed defective, just as the diagnostic suggested. In my case, the repair bill came to 980€, which covered replacing the faulty air conditioning control unit and associated parts. The cost was higher than your repair since they needed to replace the entire control module rather than just rewiring and sensor replacement. But its been worth every cent, no more false temperature readings or cooling system warnings since then. The vehicle maintenance log shows its been 14 months since the fix, and the temperature gauge has remained stable with accurate readings. The cooling system now maintains proper operating temperatures without any warning messages or malfunctions. This kind of repair might seem expensive, but preventing potential engine damage from inaccurate temperature monitoring definitely justifies the cost. Plus, having a properly functioning AC system makes driving much more comfortable.

Thanks everyone for the helpful replies. I wanted to share how my repair journey ended. After checking several shops, I finally found a good mechanic who properly diagnosed the issue. The cooling system inspection revealed both a failing temperature sensor and corroded wiring connections near the heat exchanger. During the repair, they also found minor coolant leaks around the sensor housing that needed fixing. The total repair came to 650€ including: New temperature sensor assembly, Wiring harness replacement, Coolant system pressure test, Sensor calibration, Labor costs The HVAC system now works perfectly and all engine cooling warnings have disappeared. No temperature gauge issues for the past 3 months. For anyone facing similar symptoms, get it checked properly. A thorough diagnostic saved me from potential bigger problems, despite costing a bit more upfront than a quick sensor swap would have.