Carrier 40MPHA Service Manual page 40

P0 (IPM malfunction or IGBT over-strong current protection diagnosis and solution)
Description: When the voltage signal the IPM sends to the compressor drive chip is abnormal, the display LED displays "P0" and the air
conditioner turns off.
Recommended parts to prepare:
• Wiring mistake
• IPM malfunction
• Faulty outdoor fan assembly
• Compressor malfunction
• Faulty outdoor PCB
Troubleshooting and Repair:
Check the wiring between
PCB and compressor.
Does an error exist?
NO
Check the IPM.
Is it in working order?
YES
Check the outdoor fan and the
outdoor unit ventilation.
Is it in working order?
YES
Check the compressor
resistance values.
acceptable parameters?
YES
Replace the outdoor PCB.
40
YES
NO
NO
NO
Specifications subject to change without notice.
Ensure proper connections or
replace the wires and connectors.
Replace the IPM board or
replace the outdoor PCB.
Refer to the "Fan Speed is Out of Control"
solution.
Replace the compressor.
40MPHA-03SM