You might try one of the links on Jim F.'s page:

http://pages.prodigy.net/jforgione/MB_S500.html

He has links for DTC's on on the Distributor Ignition Module and the Diagnostic Module.

If you're not sure, try e-mailing him. He's a frequent contributor to this site.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".