Get the diagnostic codes!! You won't get what you need from a generic OBD II scanner. You will need to use a scan tool that can dig into the Mercedes transmission codes. There are several on the market for about $200 or a little less, or go to an independent shop (NO Dealerships) who specialize in European cars. They can pull the codes and get you started in the right direction. GET the specific code numbers! NOT just an explanation as to what the number means. Without the codes it's just a guess.