Last time the battery was disconnected about 1200 miles ago or about 4 months ago. But as I mentioned, the problem remains the same for over 8000 miles and over 2 years period. There are no codes period! No warnings, no malfunction, no errors - nothing. It's just looks like not enough data.

I spent over 900 dollars on various unnecessary repairs and diagnostics. The car was checked by 6 shops (and not just generic shops, but Mercedes and hi-end German specialty shops). No offence to small shops, but average mechanic would't even know where to look, so I was talking to automotive electronic specialists as well (not to be confused with an electrician who knows how to replace a light bulb).

Nobody knows...