York HP Series Service Manual page 109

16.4.10 Inverter compressor drive error diagnosis and solution(P4)
Error Code
Malfunction conditions
Potential causes
Trouble shooting:
P4
Abnormalities in the inverter compressor drive is detected by a
special detection circuit, which can perform communication
signal detection, voltage detection, and compressor rotation
speed signal detection.
Wiring mistake
●
IPM malfunction
●
Faulty outdoor fan assembly
●
Compressor malfunction
●
Faulty outdoor PCB
●
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