Mercedes C Klasse Hybrid Overvoltage Issue

I had something similar with my C Klasse hybrid. Seemingly unrelated systems threw errors. It was a weird interaction between the hybrid system's high voltage components and the 12V battery. Have you checked the charging voltage output of the hybrid system? It might be overcharging the 12V battery, causing the car electronics to act up. What fault codes are you seeing?

How would you recommend I test the high voltage system's charging voltage output safely? I know the risks involved. Also, could you share the specific fault codes you saw during your incident? This would help me cross-reference with my data to pinpoint the electrical issue.

Safety is key with high voltage. Unless you're trained in hybrid vehicle electric systems, I wouldn't advise poking around too much, the voltages are dangerous. I can't recall the specific codes, it has been a while, but your symptoms sound familiar. Considering the potential for damage to sensitive car electronics and the car ECU, it might be best to get it to a workshop. They can properly diagnose the charging system and battery condition. I didn't want to risk damaging the hybrid system or creating further electrical issues.

I appreciate the advice. Your insights confirmed my suspicions. I took the vehicle to a certified Mercedes technician. The 12V battery showed signs of internal failure, leading to the overvoltage errors and system malfunctions. The repair, including a new battery and diagnostic assessment, totaled 290€. Thanks for sharing your experience; it guided my actions.