Hello assane_s,
in my table of errors I have this information:

error 405 - battery voltage - over voltage
error 416 - drive current sensor - V phase low output

*error 405
1. check the battery voltage
2. check the main cables to traction board
3. check the batteries and battery compartment
4. looking in to the schematic, the only device that could be measuring voltage is the traction board itself, so if 1, 2 & 3 is OK you could have a faulty board.

*error 416
The drive current sensor is actually just a coil around the V phase of right drive motor. It picks up magnetic field from passing current in the cable and obviously creates a small current that can be measured by the traction board.
1. Check continuity (OHM) of the coil
2. Check power supply and wiring to the coil
3. looking in to the schematic, the only device that could be measuring current is the traction board itself, so if 1 and 2 is OK you could have a faulty board.

I hope I have helped you.
Regards.