Howdy Selma,
Wow that's a sad story--sorry to hear that the dealer has hosed you on the diagnostics.
They should have connected the MUT-3 tool and read out the diagnostic trouble codes; then there are troubleshooting steps for all the DTCs.
The on-board charger is on the left in your picture, with the integrated DCDC Converter in the bottom plenum. The box on the right is the Motor Control Unit, aka drive inverter. Neither box has any function or connection related to Chademo charging, so the story is somewhat confusing.
If the DCDC converter was bad, then either the entire OBC unit could be replaced, or the circuit board in the bottom plenum could be repaired or replaced from a used unit. Some of the OBC units were given an extended warranty due to failures so it might not hurt to check with a different dealer or Mitsubishi corportate about this.
It is possible that the DCDC failed, but it is not a common failure. The DC converter functions to recharge the 12V battery located up under the front hood.
An old, weak or worn out 12V battery can cause a multitude of faults such as the car not starting to READY that you experienced. Is it possible that you have maintained your 12V battery by keeping it fully charged all the time during this period of non-use?
There is a fuse inside the MCU that is inline with the HVDC from the pack to the DC converter. There are also fuses inside the OBC and on the DC Converter board. If any of those happened to blow then the DCC might be disabled, but the car should still start to READY.
Maybe a member out there in cali can give you some help reading the DTCs and we could repair your OBC/DCC.
Here is a thread about troubleshooting and repair of the OBC/DCC. The forum has much more experience and knowledge about these cars than any dealership.
Troubleshooting and repair for On-board Charger (OBC)
