Carrier / Comfort 22
Carrier PC04 error code
PC04 means the inverter compressor drive reported an error. The compressor-drive electronics or compressor circuit need technician diagnosis.
- Urgency
- advisory
- Verified
- Jul 31, 2026
- Fix path
- Technician
What it means
PC04 means the inverter compressor drive reported an error. The compressor-drive electronics or compressor circuit need technician diagnosis.
Urgency
advisory
Try only the safe reset/check in the owner's manual. If the code returns, stop using the system until it is diagnosed.
Likely causes
- Carrier Table 4 identifies PC04 as inverter compressor drive error.
- Carrier troubleshooting lists compressor broken, voltage too high/low, circuit blockage, and refrigerant amount conditions as possible causes a technician may evaluate.
Homeowner fix
Turn the system off with the remote, wait about 10 minutes, then power cycle once at the breaker or disconnect if you can do that safely. If the code returns, stop resetting and schedule service. Do not open the indoor or outdoor cabinet.
When to call a pro
Call a licensed HVAC technician if PC04 returns after one safe reset. Tell them Carrier identifies PC04 as inverter compressor drive error.
This code points to refrigerant or sealed-system, compressor, and electrical or inverter work - get repair quotes from contractors in your area.
Get repair quotesRepair vs replace
This is normally a repair diagnosis, not an automatic replacement signal. If a technician confirms a major board, compressor, fan-motor, or sealed-system repair on older out-of-warranty equipment, compare the quote with replacement.
See Carrier mini-splitsYour Carrier model
Comfort 22 model pages in the Carrier catalog help compare this repair path with current replacement options.
- Carrier Comfort 22 9,000 BTU R-454B 115V (45MHHAQ09XC1 / 37MHRAQ09AA1)
Comfort 22
- Carrier Comfort 22 9,000 BTU R-454B 208/230V (45MHHAQ09XC3 / 37MHRAQ09AA3)
Comfort 22
- Carrier Comfort 22 12,000 BTU R-454B 115V (45MHHAQ12XC1 / 37MHRAQ12AA1)
Comfort 22
- Carrier Comfort 22 12,000 BTU R-454B 208/230V (45MHHAQ12XC3 / 37MHRAQ12AA3)
Comfort 22
For your technician
Technician note: diagnose compressor winding/insulation, inverter drive output, IPM/PCB, supply voltage, refrigerant circuit, and related fault history. Page context: Carrier maps this display to the Comfort 22 line; source: Carrier 45MHHAQ High Wall Heat Pump Owner's Manual, Table 4 Error Codes; display convention: match the letter P, letter C, and four marker exactly before comparing neighboring codes.
Which systems show it
Comfort 22
Related troubleshooting
Use the symptom guide alongside the exact display code if the unit is flashing, cycling, or showing comfort symptoms.
Related codes
Source
- Document
- Carrier 45MHHAQ High Wall Heat Pump Owner's Manual, Table 4 Error Codes