I have a problem with my 02 C240 and need to get the error codes out of the computer to figure out what to do next. Any help would be greatly appreciated! Thanks, Ben
I picked up a OBD II code reader from Harbor Freight. It reads the codes from your car's computer, clears the Service Engine light, and comes with a book + CD ROM that can interpret the codes for you. Cost about $45, but Harbor has frequent sales where you might get a discount.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94169 (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94169)
There are some really good online M-B forums - I belong to two of them. MBWorld.org and benzworld.org are really busy places and each can be a good resource for an M-B owner. However, as you might expect there are not a lot of true expert M-B technicians that hang out online. You might find info to at least diagnose your car, though.
Where in MN do you live? If you're trying to avoid a dealer's exhorbitant costs, there's a great independent shop near my house that I'm happy to recommend.