Mercedes W212 | Keyless-Go Repair
It's likely a common issue caused by the deterioration of the seal layer around the door handle, leading to moisture ingress and cable breakage.
I had following fault code
(9A4A14 the keyless-go sensor in the left front door handle has a malfunction. There is a short circuit to ground or an open circuit.)
Thanks to @luked272 for the fast help regarding how the keyless-go system works!