Midea Mono 3D - Main Parts Check and Testing; 1. Temperature Sensor Checking

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9.3.10 Inverter compressor drive error diagnosis and solution(P4)
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 ass’y faulty
● Compressor malfunction
● Outdoor PCB faulty
Trouble shooting:
Check if the wiring between main
PCB and compressor connected by
error and if the wires and connectors
are broken?
Correct the connection or replace the
wires and connectors.
Yes
No
IPM continuity check. Check if the
IPM terminal resistance values are
uniform. Refer to page 64.
Replace the IPM board or replace the
main PCB if the IPM board and main
PCB are integrated together.
No
Check if the outdoor fan runs
properly or the outdoor unit
ventilation is good.
Yes
No
please refer to the solution of fan speed
is out of control.
Yes
Check if the compressor resistance
values are uniform .Refer to page 63.
No Replace the compressor.
Yes
Replace the outdoor main PCB if the
main PCB and IPM are separate.