Mercedes S Klasse Hybrid Transmission Issue Resolved

That sounds frustrating. I had something similar with my old Volvo V70, though it was a gasoline engine. Warning lights, emergency mode, and rough shifting often mean a temperature sensor issue or low fluid. It's like your gearbox is running a fever. A faulty gearbox sensor can mess things up. Have you checked the transmission fluid level? If your Mercedes has a dipstick, use it. If the level is low, that could explain the sensor error and problems. But even if the level is okay, the sensor itself might be bad. Did the error code specifically mention the temperature sensor?

Yes, the error code points to the transmission oil temperature sensor. I haven't checked the fluid level yet. Can a bad temperature sensor trigger emergency mode even if the fluid level is fine?

Definitely. Think of the temperature sensor as the transmission's nervous system. If it sends wrong info, like saying the oil is super hot when it's not, the car will likely trigger emergency mode to be safe. The grinding noises, though, might mean something worse inside the gearbox, maybe needing transmission repair. I'd get your Mercedes to a good shop for a checkup. It's best to have a pro diagnose it before more damage happens. Replacing the gearbox sensor might fix it, but a damaged transmission is a big deal.

I took the car to a Mercedes-Benz service center. They said the transmission oil temperature sensor was faulty due to low gearbox oil. They replaced the sensor and fixed the oil level. The total cost was 365€. The gear shifting is now smooth, and the warning lights are off. Thanks again for the help.