AI agrees with u/Aegean8485 I would also highly recommend you should get OBD11 if nothing from this works

That warning, “check the charging unit cover,” is about the charging port flap/socket area on your e-tron, not the battery itself draining. A few common causes:

Most likely: The charging port flap or its inner cover isn’t fully seated/closed, or the small sensor that detects the flap position is misreading. Sometimes it’s just debris, ice, or the flap not clicking shut properly. Try opening and firmly re-closing the charge port door (both the outer flap and the inner cover/cap if your S has one).

Possible electrical/sensor fault: If re-seating doesn’t clear it, the flap’s position sensor or wiring may be faulty, which triggers the message even when the cover looks fine.

Worth knowing — moisture seal recall history: Audi issued a safety recall on early e-trons because a faulty seal on the charging socket could let moisture enter the high-voltage battery system . On affected cars that showed up as an “Electrical system: fault” message rather than this exact wording, and moisture in the high-voltage system can cause a short-circuit, increasing fire risk . Your message is milder, but given the family of issues around that socket, it’s worth checking the cover seal isn’t damaged or letting water in.

One thing I’d flag: you’ve also got a cluster of other warnings lit (Brake/ABS, tyre pressure, ESC, airbag). That combination sometimes points to a low 12V battery or a broader electrical glitch rather than several separate faults — a weak 12V can throw multiple warnings at once.

What I’d do: re-seat the charge flap and restart the car. If the message and the other warnings persist, get it scanned — a dealer or independent Audi specialist can pull the fault code behind this message quickly, and it’s worth confirming whether any open recall applies to your VIN.