Carrier 40MPHA Service Manual page 31

DIAGNOSIS AND SOLUTION (CONT)
P4 (Inverter compressor drive error diagnosis and solution)
Description: If the temperature of IPM module is higher than limited value, the LED displays this failure code.
Recommended parts to prepare:
S
Wiring mistake
S
PM malfunction
S
Outdoor fan assembly faulty
S
Compressor malfunction
S
Outdoor PCB faulty
Troubleshooting and Repair:
Check the wiring between the
Check the outdoor fan and
the outdoor unit ventilation
acceptable parameters ?
Replace the outdoor PCB
PCB and compressor
Is it improperly wired ?
NO
Check the IPM
Is it functioning
properly?
YES
Is it functioning
properly?
YES
Check the compressor
resistance values.
Are they within
YES
Ensure proper connections or replace
YES
the wires and connectors
Replace the IPM board or
NO
replace the outdoor PCB
Please refer to "Fan
NO
Speed Malfunction"
NO Replace the compressor
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