I would call independent, MB-specific shops in your area until you find one that will read the codes with the proper equipment. Once you have the codes... you could have the shop trouble shoot it for you or, perhaps, ask the members of this forum for help you figure it out. Not that it really applies to your situation, but at 75,000 miles my CE light came on and it ended up being the mass airflow sensor. I had it replaced and not one issue since then.
1988 300 SL (5 Speed)
1994 E320 Wagon