check this site out: http://www.obdii.com/obdii.html
Click on 'Does my car have OBD-II'.
It shows what and when they became OBD compliant, fully or partially. Accordingly it says that the C220 was not FULLY
compliant but obviously somewhat!
What this all means is that you MAY
have an alternate way of looking at codes; the 38 pin Diagnostic connector (X11/4).
If so, the codes that you see on my page are taken from the 38 pin Diag connector and are MB 'english' codes rather than more crytic OBD codes. The OBD codes were shorten abit and coded with 'P' numbers. Yes, the codes are related but I don't know how to make the association unless you have two scanners: One such as the AST 'Retriever' and an OBD version. Read the codes using both and the 'P' numbers will get cross-linked.
To me it's better to read the DTCs from the Diag connector (if you can) than from the OBD one. But not sure that the 38 pin connector was not eliminated!
David Klasse would know!