Each time I park my Mercedes Benz w202 over night. What I discovered next day was a flat battery the car would not start again.. I run scan on the said car no solution yet...
A scan is not going to show anything. What you have is a system not going to sleep and draining the battery.
You need a multimeter that can measure current draw. Then pull one fuse at a time and check which system is drawing over 0.3A.
Start with the audio gateway. If not that check the rest of the circuits.
Check out this video on how to find a parasitic darw.