Mini Roadster Temperature Gauge Issues

Interesting issue you're describing with your Mini Roadster. I had a similar problem with my car. The error memory and lack of AC functionality point to a problem within the HVAC system. The temperature gauge behaving erratically is also a key symptom.

Thanks for the quick reply! Coolant level seems okay, no obvious leaks. Engine temp is normal too, needle sits right in the middle. The weird thing is the error code specifically mentions the heat exchanger temperature sensor. Any chance it's just a faulty sensor, or is there more to it?

Considering the error code you're seeing and the symptoms, it's very likely the temperature sensor on the heat exchanger itself. While a faulty AC control unit can cause similar problems, the direct error code points to the sensor. Given the relatively low mileage, it's possible the sensor failed prematurely due to a manufacturing defect or external factors. I suggest you take it to a qualified mechanic for proper diagnosis and replacement. They can confirm the sensor is indeed the issue and ensure the new one is correctly installed and calibrated. It's also worth pressure testing the cooling system to rule out any underlying coolant leak that may have contributed to the sensor failure.

Seems like the same story with my Roadster. Ended up taking it to a local independent shop, and you were spot on – heat exchanger temperature sensor was indeed fried. They replaced it, did a pressure test to check for coolant leaks, and now the AC is blowing cold again! Cost me around 980€, but at least it's sorted. Really appreciate the help!