Outdoor unit display  LED STATUS 
P0  Temperature protection of compressor top. 
Off: 105c;    On: 90c 
The trouble shooting is same with the one of indoor unit P2 protection. 
 
Outdoor unit display
  LED STATUS 
P3  Compressor current protection 
 
 
 
Outdoor unit display
  LED STATUS 
P4 
Inverter module protection 
The trouble shooting is same with the one of indoor unit P0 protection 
Check the resistance of compressor, normally   
U and V is 0.6 ohm 
U and W is 0.6 ohm 
V and W is 0.6 ohm 
Turn one indoor unit only, Does the compressor start after 
3 minutes?  
Does the trouble occur again after compressor 
running some time?
 
No 
Yes 
No 
The compressor is defective 
Check the refrigerant circulation volume and pressure 
No 
The compressor is defective 
Yes 
If refrigerant circulation volume and pressure is OK, change the outdoor main PCB.