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5.12  P4(Inverter compressor drive error diagnosis and solution)
Description: An abnormal inverter compressor drive is detected by a special  detection circuit, including communication 
signal detection, voltage detection, compressor rotation speed signal detection and so on.
Recommended parts to prepare:
• Wiring mistake
• IPM malfunction
• Faulty outdoor fan assembly 
• Compressor malfunction
• Faulty outdoor PCB 
Troubleshooting and repair:
Check the wiring between the 
PCB and compressor.
Is it improperly wired?
Ensure proper connections or replace 
the wires and connectors.
YES
Check the IPM.
NO
Is it functioning 
properly?
Replace the IPM board or 
replace the outdoor PCB.
NO
Check the outdoor fan and 
the outdoor unit ventilation.
YES
Is it functioning 
properly?
Please refer to “Fan 
Speed Malfunction”
NO
Check the compressor 
resistance values.
YES
 Are they within 
acceptable parameters?
Replace the compressor.NO
Replace the outdoor PCB.
YES