Thank you kiev for the detailed information. That was what I needed. I'll try to remove the MCU and check if there are some faulty elements in the circuit. The car cannot start because the ECU can't measure the voltage of the capacitor.
I'll try to take some measurements and see if I can find the culprit that messes with the measurement. It will be hard to measure and debug the circuit. I hope that I don't blow anything and fry the inverter board. Probably I should look for someone with more experience in these kind of things.
If something wrong happens I'll have to go by Lic's steps or to find another way to put a custom MCU and try to make it work.
I hope Lic manages to fix his problem with the new MCU and get back on the road.