CrosslandX Transmission Oil Temperature Sensor Fault

I have the same model, and experienced similar issues not too long ago. I had the engine warning light illuminating, and also faced some issues with the gear changes not being as smooth as they should be. By 'emergency mode', I assume you are referring to the car limiting the available gears and speed for protection, which I also encountered. The grinding noise is not something I personally heard, but that does not mean much. Did you check the oil level of the gearbox?

I haven't checked the gearbox oil level myself, to be honest. I wasn't sure where to start with that, and whether it's something I could easily do at home. Is it a straightforward process, or would it be better to have a professional take a look?

Given your description, it would be prudent to have a qualified technician inspect the vehicle. While checking the gearbox oil level might seem simple, it can be rather involved depending on the specific transmission type. Furthermore, the grinding noise you mentioned indicates that there may be existing damage within the gearbox. Continuing to drive the vehicle in its current state could exacerbate the problem. A workshop can properly diagnose the root cause and determine whether it is, in fact, a low oil level or a more serious issue with the transmission. Replacing the temperature sensor might be necessary to resolve the error codes, but it will likely not fix the core mechanical issues. I would recommend booking an appointment with a trusted mechanic.

Took it to a mechanic, and you were spot on. Turns out the gearbox oil level was indeed low, causing the temperature sensor to go haywire. They topped it up, replaced the faulty sensor, and the grinding noise is gone, shifts are smooth again. The final bill came to 365€.