S Klasse Hybrid Vehicle Battery Issues

I had a similar issue with my S Klasse. Intermittent electrical issues can be a pain. Did you check the battery voltage? A defective sensor will cause parasitic vehicle battery drain, even when the car is off, leading to a discharged battery. Do you know how old your current vehicle battery is?

I have not yet checked the battery voltage directly; however, the error message does suggest a potential issue with the battery's state of charge. Regarding the battery's age, it is the original one installed when the vehicle was manufactured. Could the defective sensor cause a complete battery failure, or is it more likely to simply accelerate the discharge process?

A defective sensor definitely accelerates the vehicle battery discharge. Given the age of the battery and your symptoms, I'd suggest having the battery and sensor checked by a workshop. It may be time to replace the battery anyway.

I took the vehicle to a workshop, and as you suspected, the battery sensor was indeed defective, causing a persistent battery drain. The sensor was replaced, and the total repair cost was approximately 315€. The error messages have disappeared, and the vehicle starts without issue now.