You need to look that code up in the service manual. It refers to the senor inside the gas tank, so it could be bad wiring from the top of the tank to the PTCM or a bad sensor. A stuck purge solenoid can cause the code to trip but the DTC refers to the sensor not the EVAP system. I do not know what scan tool you are using, but if it is a generic OBD tool it may be giving you a false DTC. It is best practice to scan with a tool that can get into the Mercedes codes on the Crossfire.

Are you having any trouble filling the gas tank ?

This has to be frustrating; Hang in there.