Could be a worn out USB Jack in the Multimedia Control Unit.
I was on a road trip (typical) with my 2019 C43 when my Android Auto started acting up and would eventually fail to connect after trying for 1-2 seconds. Same result with my spouses phone as well as after swapping out a different USB cable. While our phones connected perfectly with our other car.

Turns out to be a ~$100CAD part 205 820 20 03 for the W205 that fixed it all up. I found a few no name options on AliExpress that were $80 - didn't think the small cost saving was worth the gamble

After a bit of research and looking at threads I found a few difficult ways (full centre console disassembly) and an easy way (<5 minutes) to replace it and wanted to share and give back to the community

First up the unit installed, it's the module with the orange backlight USB-A port on it




There is a notch and a tab at the top and the bottom, a spudger or old feeler gauge is perfect to get in there and release the tab, here is a picture of the notches on the top and bottom you are aiming for - they aren't visible when it's installed - you need something flexible, yet firm enough to push on the tab


Here is a picture of the feeler I used that got bent up a bit showing the tab you are targeting - if you push in on the tab, it will release, repeat on the other. I had a popsicle stick on standby to stop it from reattaching , but wasn't needed.


NOTE: a good tip Is to tie a shoelace or string to the cable before you detach it from the dead unit, in case it attempts to escape back into the hole into the depths of the centre console - I used blue in my case:


The white connector on the back is simple to remove (relative to most under hood sealed gernan connectors), just one tab to depress circled 2 pictures above.

• Swap in the new module,
• Remove the shoelace,
• Fire up the car,
• Connect the USB cable
• Reinitialize and pair your phone
• Try out Android Auto
• If everything checks out, push the module back into the cavity until it clips back in and you are done

Here is the OEM replacement package and markings for reference


Happy motoring

 

Thanks for sharing this detailed guide! It sounds like a straightforward fix once you know where to apply pressure and handle the tabs. I’ll keep this in mind if my Android Auto acts up, and the shoelace tip is genius for preventing cable slip! Great work and happy motoring!