Tourneo AC Temperature Sensor Issue

Sounds familiar. I had a similar problem with my Tourneo's AC. Is it like your engine's overheating, but only the AC knows about it? Check the simple things first, but it might be the sensor.

Were your symptoms exactly the same – the error message, the AC refusing to operate? Did the diagnostics also point to the AC control unit or the temperature sensor?

Yup, same deal. Error light and no AC. I fiddled with it for a bit, but eventually, I gave up and took it to a workshop. They sorted it out. Save yourself the headache and get it checked professionally. Probably the sensor as the computer says.

It seems my initial assessment was accurate. I'll take it to a qualified workshop. It was indeed the temperature sensor heat exchanger defective, after being replaced the problem was resolved.