I bought a new Mercedes-Benz C220 CDI (W204) last month and had a Westfalia towbar fitted by the local dealer that the M-B dealer recommended, all worked fine.

I was also told that the appropriate code then had to be programmed back at the M-B dealer. However, after programming, I now get a warning in the speedometer
saying "Malfunction See Owners Manual" when I switch the ignition on and off.

The mechanic said this was due to a non-M-B towbar being fitted. However, Westfalia supply the factory fitted option and I specified the correct car-specific electric wiring kit should be fitted.

Can you kindly confirm whether this message should be displayed? I am not clear how I am supposed to recognise a proper malfunction if I get this message each time I switch on.