LG MULTI V M ARNU07GTU 4 Series Svc Manual page 72

Troubleshooting Guide
Error
Error Type
No.
Sensor error of low
421
pressure
Sensor error of high
431
pressure
n Error diagnosis and countermeasure flow chart
Is sensor connected
to PCB correctly?
Yes
After replacement of
Compressor Module main PCB
is the system normal?
Yes
END
Error Point
Abnormal value of
sensor
(Open/Short)
Abnormal value of
sensor
(Open/Short)
No
Connect sensor to PCB correctly
No
Replace corresponding
pressure sensor
Pressure sensor connector
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Main Reasons
1. Bad connection of low pressure connector
2. Defect of low pressure connector (Open/Short)
3. Defect of outdoor PCB
1. Bad connection of high pressure connector
2. Defect of high pressure connector (Open/Short)
3. Defect of outdoor PCB
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