When the voltage signal the IPM sends to the compressor drive 
chip is abnormal, the display LED shows “P0” and the AC turn 
off. 
Check the wiring between main PCB 
and compressor. Does an error 
exist?  
Ensure a proper connection or 
replace the wires and connectors
Yes
No
Check the IPM. Is it in working 
order?
No
Yes
Replace the IPM board or replace 
the main PCB
Check the outdoor fan and the 
outdoor unit ventilation. Is it in 
working order?
No
Please refer to the solution to the 
“fan speed is out of control” 
malfunction
Yes
Check the compressor resistance 
values. Are they within acceptable 
parameters?
No Replace the compressor
Yes
Replace the outdoor main PCB