If you have a vac on the system you and hooked up a can , it should have sucked that can dry in no time..I think you have not opened the charge valve all the way..I believe the pressure reading ou are seeing is CAN pressure.

As far as the drier sensor, I have not seen that type and only have schematic/info on the E class. ..if that is a variable resistor , it would be an electonic pressure sensor [ as opposed to a mechanical]..I am sure MB Doc knows , so that should be correct info.
You can tell for sure with ohm meter. but I am sure he is correct.

I don't think you have transferred any refrig from can to system..is can EMPTY ????????