Hey, this looks like a great forum... Glad I found it.
My check engine light came on last week on my 1998 E320, with the dash display telling me there is a problem with the engine electronics. So I ordered an Auterra OBD scanner to use with my Treo 650 phone. Apparently that phone will do everything except wipe my rear.
The literature available on the web for the scanner (I haven't received it yet) says that it works with all 1996 and later OBD systems, including the ISO 9141 standard that is used on Mercedes.
But now I'm concerned about the connector. The scanner interfaces with the standard oblong 16 pin OBD. I've located the 38 pin round diagnostic connector in the engine compartment, but I've also found reference to the standard 16 pin connector being under the driver's dash on the Mercedes
http://www.whnet.com/4x4/diagnostic.html. Does my car have both? It seems like I would have an easier time finding a jumper cable if I have to use the 38 jack (I found this
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150090668024 on ebay, but it has to come from England).