Haier AU042FPERA Service Manual page 59

[75-0, 75-4] Pressure difference between high pressure and low pressure is abnormal
Check if high/ low pressure
sensor is connected well
Check if compressor wire is
If wire of inverter compressor
are connected oppositely
Measure if there is voltage
U, V, W of compressor by
multimeter, and if it is normal
Replace inverter compressor
Yes
connected normally
Yes
No
If 4-way valve is
interconnected
No
Yes
No
Re-connect
No
Correct compressor wire
No
Correct compressor wire
Yes
Replace 4-way valve
No
Replace inverter module
57