Ka transmission oil temperature sensor error

That sounds frustrating! I had a similar issue with my old Opel Astra, although it was a petrol engine. The symptoms were almost identical - warning lights, rough shifting, the whole shebang. Turns out it was also related to the transmission, though in my case the sensor itself was faulty and needed replacing. Have you checked the oil level?

Thanks for the quick response! I haven't checked the oil level myself yet, to be honest. I'm not really sure how to do that on this model. Was it a difficult process on your Astra? Did replacing the sensor solve all the issues, or did you have to do anything else?

Checking the level on the Astra wasn't too bad, but every car is different. Given all the symptoms you're describing – especially the grinding noises – I'd seriously consider getting it checked by a professional. In my case, replacing the sensor sorted out the warning lights and the emergency mode, but the rough shifting persisted until they flushed and refilled the transmission fluid. Best to get a proper diagnosis before things get worse.

Okay, I appreciate the advice. Sounds like it's best to take it to a workshop. I did just that, and it turned out the gearbox oil level was indeed too low, causing the sensor to go haywire. They topped it up and replaced the sensor as a precaution. Total cost was 365€. Now it runs smoothly again. Thanks again for your help!