38MBR: Service Manual
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33
Inverter Compressor Drive Error Diagnosis and Solution (P4)
Troubleshooting
Error Code
P4
Malfunction decision conditions
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.
Supposed Causes
• Wiring mistake
• IPM malfunction
• Outdoor fan assembly fault
• Compressor malfunction
• Outdoor PCB faulty
Check the wiring between the
main PCB and compressor.
Is it improperly wired?
Check the IPM.
/ƐŝƚĨƵŶĐƟŽŶŝŶŐƉƌŽƉĞƌůLJ͍
No
Yes
Check the outdoor fan and the
ŽƵƚĚŽŽƌƵŶŝƚǀĞŶƟůĂƟŽŶ͘
/ƐŝƚĨƵŶĐƟŽŶŝŶŐƉƌŽƉĞƌůLJ͍
Yes
Check the compressor resistance values.
Are they within acceptable parameters?
Yes
Replace the
outdoor main PCB.
ŶƐƵƌĞƉƌŽƉĞƌĐŽŶŶĞĐƟŽŶŽƌ
replace the wires and connectors.
Yes
Replace the IPM board
or replace the main PCB.
No
Please refer to
͞&ĂŶ^ƉĞĞĚDĂůĨƵŶĐƟŽŶ͟ƐĞĐƟŽŶ͘
No
Replace the compressor.
No
