Master Defective Temperature Sensor Air Conditioning Failure

Temperature sensor in the heat exchanger causing all that? Hmm. It does sound like a cascade of failures stemming from a single point. But defective how? Have you checked for coolant leaks around the heat exchanger? A low coolant level can definitely mess with the temperature readings and shut down the AC as a protective measure. Also, has anyone attempted sensor calibration or looked at the HVAC system pressures? Low refrigerant could also be a factor. So, is it definitely the sensor itself or something affecting its readings?

Good shouts! Coolant level is fine, I've checked that religiously. No obvious signs of a coolant leak anywhere either. As for sensor calibration and HVAC pressures, I haven't dug that deep yet. I was hoping it was going to be something simple to fix, but am thinking now that it's all interconnected. How easy would it be to check the HVAC pressures or calibrate the sensor myself? Is it something requiring specialist tools?

Yeah, HVAC pressures and sensor calibration need specialist tools, and honestly, a bit of know-how unless you want to risk making things worse. Given the symptoms and error codes, I'd suggest taking it to a decent workshop. The fact the AC isn't working makes me think it's more involved than just a dodgy sensor. It sounds like the air conditioning control unit might be actually defective.

Cheers. I was really hoping to avoid a big bill, but it sounds like I'm out of my depth here. Bit the bullet and took it to a specialist. They confirmed it was the AC control unit being defective and playing havoc with the temperature sensor readings. Estimate for repair? A painful 980€. Thanks again for the advice!