DoIP Explained: Why 2016+ Mercedes and BMW Won't Talk to Old Interfaces

Since roughly 2016, both Mercedes and BMW route diagnostics over DoIP — Diagnostics over Internet Protocol — on pins 3, 8, 12 and 13 of the OBD port. Your classic K-Line pin-7 interface sees nothing on these cars.

What this means in practice

• Star-style C3 and early C4 clones cannot reach any module on W205, W213, W222 or newer.
• BMW F-series coding works over ENET, but G-series programming requires ENET with DoIP firmware or ICOM NEXT.
• Expect download-heavy routines — a control-unit flash over DoIP takes 15–40 minutes vs 2+ hours on CAN.

The SDconnect C6 in our catalog is a DoIP-native multiplexer — it also emulates C4 mode for older vehicles, so one interface covers the whole Mercedes range from 2009 onward.