Mercedes Errorscodes

Hi
I find it very difficult to find any information regarding the last parts of the Mercedes errorscodes. No problem finding the generic ones, like P2279, but P227964 or 227962 is another matter. Would be nice to know the last part of the code, that could perhaps narrow down the search.
I got hold of all the partslists and workshops manuals for Mercedes, but finding the Mercedes error codes is not so easy.

Any ones knows where to find them?

Regards
Lars