Corolla AC Compressor Undervoltage

That's a tricky one! Sounds like your Corolla is having a hot flash. Since you've checked fuses, is the compressor engaging at all? Can you hear it click when you turn on the A/C? If not, it could be the A/C relay or the pressure switch. If the pressure is too low or too high, the switch will prevent the compressor from kicking in to protect it. Has the belt tensioner been checked? Did the compressor ever make strange noises?

There is no audible 'click' when the A/C is engaged, suggesting the compressor isn't initiating. Regarding the pressure switch, is there a way to assess its functionality without specialized diagnostic equipment? The belt tension seems alright, not too tight or loose. The compressor never made strange noises before shutting off.

With no click from the compressor, it sounds like an electrical issue or the pressure switch, but without being 100% sure. You could try locating the pressure switch and seeing if it has power going to it when the A/C is turned on, but without the proper tools, it's difficult. Given the error code and the lack of engagement, it might be best to take it to a workshop. They'll have the equipment to properly diagnose whether it's the relay, pressure switch, or something else entirely causing undervoltage issues.

I took the car to a trusted workshop. The issue was indeed related to undervoltage. The A/C compressor had shut off. The repair cost 240€.