In the service manual, it says this for that code:
"U3000:04 Control Module: System Internal Failure INSTALL a new SOBDM .
REFER to: Secondary On-Board Diagnostic Control Module A (SOBDM) (414-03B High Voltage Battery Charging System, Removal and Installation)."
But it also says this:
"U3000:41 Control Module: General Checksum Failure CLEAR the DTC . REPEAT the self-test. If the DTC is still present, INSTALL a new GFM .
REFER to: Generic Function Module (GFM) (414-03B High Voltage Battery Charging System, Removal and Installation)."
So the SOBDM is the charger, the GFM is the module that deals with the lights and logic on the charge port.
You could use Forscan to reset and selftest the modules. I would think the GFM to be a much cheaper replacement part than the SOBDM. It could be a bad connection, or it might be a blown fuse inside of the SOBDM.