Ethan,

Thanks for the info. I will try that URL. Maybe I can find out some more info on my problem. I called MB (long distance) and asked about the DTC's that I pulled.
Just in case you're interested, here they are.
The P1235 is; Reciculated Air Flap Signal Output Stage
P1236 is; Compressor Output Stage Magnetic Coupling.
P1420 is; Air Pump Switchover Valve
P1525 is; Camshaft Timing Actuator
My scanner displayed the correct codes, just not the correct discription.
So, if I can't find out anything at the URL that you have provied, I guess that it's time for me to plan on a 2 hour (one way) to my MB dealer.
Again, thank you. Carl