On your C280, the connector for the generic scan tool for OBD codes I believe is located in the drivers footwell under the dash. I don't believe there is any way to retreive the codes without at least a generic scan tool.
All OBDII codes are identical as to their meaning, so if you have the list of OBDII codes, they need to apply to your car by Federal law.
Some of the better scanners will also go into other systems in the vehicle other than the engine management, I believe the real nice ones will give you many of the proprietary codes also.
Most scanners will give you the OBDII and proprietary codes meaning.