PURY P350 YGMA Has been out of commission for a couple of years and recently powered up, none of the indoor units ran, then a fault code 0403 appeared.
Power down and reset had no effect.
Using SW1 dip switches at the outdoor unit displayed fault 0403 - 5 which suggests there is a serial transmission abnormality with the fan inverter system.
The fan board inputs were 590 VDC and 22 VAC no output measured for the fan, though fan windings have continuity at 39 - 40 - 38 Ohms.
Fan spins freely with no obvious mechanical issue.

Changed the Fan inv. board, checked wiring, cables etc for poor connections. but this didn't resolve the issue.

Anyone got any suggestions or could point me at something I may have overlooked.

regards