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Carrier Air Conditioner P3 Error Code
Too cold outside to heat on Carrier air conditioners.
CarrierAll Carrier air conditioner codes
The heat pump has paused heating because it's below its operating range outside. On the 40MHH it kicks in after the outdoor temperature sits under -13°F (-25°C) for an hour.
Compatible models
Carrier 40MHH high-wall ductless heat pumps (40MHHQ models) in heating mode, per the 40MHH service manual.
Also shown as
It restarts by itself once it warms up: above -7.6°F (-22°C) for 10 minutes after the compressor has been off an hour, or above 23°F (-5°C) for 10 minutes.
Difficulty
Most people can clear this one at home with simple checks.
Not sure you are reading the code right? See how to read Carrier air conditioner codes.
How to fix Carrier P3
Use backup heat
Run another heat source for the cold snap. The unit will pick up again as the temperature climbs.
Brush snow off the outdoor unit
Clear the top, sides and base so the unit can defrost and drain when it restarts.
When to call a technician
Call a technician only if P3 shows when it's well above those temperatures outside, which would point to a sensor problem.
Parts linked to P3
These are the parts most often behind this code. Tap one to see what it does and the signs it is failing.
Order parts by your full model number so they fit.
Frequently asked questions
Which Carrier models show the P3 code?
Carrier 40MHH high-wall ductless heat pumps (40MHHQ models) in heating mode, per the 40MHH service manual.
Can I fix Carrier P3 myself?
Usually, yes. Most P3 problems clear with simple checks you can do at home. Start with the first step above: use backup heat.
Other Carrier air conditioner codes
- Solid / 1 / 2Status light showing normal operation
- 16Lost communication with the Infinity control
- 25Model plug missing or wrong
- 31 / 84High-pressure switch tripped or locked out
- 32 / 83Low-pressure or discharge temperature trip
- 45Outdoor control board fault
- 46Brown-out: supply voltage too low
- 47No 230-volt power reaching the outdoor unit
- 53 / 55 / 56Outdoor air or coil sensor fault
- 71 / 72 / 81 / 82Compressor thermal cutout or lockout
- 73 / 74Contactor stuck closed or not closing
- E1Ductless indoor and outdoor units not talking
- ECRefrigerant leak detected
- E3 / F5Ductless fan speed out of range
- E4 / E5 / F1 / F2 / F3Ductless temperature sensor open or shorted
- F0 / P1Ductless overcurrent or voltage protection
- P5Multi-zone mode conflict
- CL / dFFilter reminder or defrost in progress
Last reviewed 2026-10-22. Codes and steps can vary by model; check your owner's manual.