VRF |How to rectify error code E9U2 & E931| Fujitsu

Brand : Fujitsu VRF model : AJY126LALBH (main CU) model : AJY072LALBH (slave 1 CU) 1)error code E9U2 (main CU) 2)error code E931 (slave 1 CU) Suspect error ; 1) E9U2 - outdoor slave unit error, error signal received from slave unit of same refrigerant system. 2)E931 - outdoor unit inverter compressor start up problem. - Inverter PCB to inverter compressor wiring disconnection, open - inverter PCB detective - inverter compressor detective (lock, winding short. #bonmj