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Carrier Air Conditioner 25 Error Code
Model plug missing or wrong on Carrier air conditioners.
CarrierAll Carrier air conditioner codes
The outdoor board reads a small plug that tells it the unit's size and type. Code 25 shows when that plug isn't found or doesn't match, and the unit won't run until it's sorted.
Compatible models
Listed for the Infinity 24ANB7 two-stage air conditioner and the 25HNB6 and 25HNB9 two-stage heat pumps.
Also shown as
Expect it after a control board swap. A replacement board carries no model information of its own, so the plug from the old board has to be moved across.
Difficulty
Try the basic checks, but the usual fix is a technician's job.
Not sure you are reading the code right? See how to read Carrier air conditioner codes.
How to fix Carrier 25
Note when it started
If the code appeared right after a repair or a new board, call the company that did the work. They need to fit the correct plug for your model.
Leave the control box closed
The plug is on the board inside the outdoor unit's electrical box, next to 230-volt wiring. Don't remove the panel to look for it.
When to call a technician
This is a technician fix in every case: the plug has to match the unit's model number exactly.
Parts linked to 25
These are the parts most often behind this code. Tap one to see what it does and the signs it is failing.
- model plug
- Outdoor control and inverter board
Order parts by your full model number so they fit.
Frequently asked questions
Which Carrier models show the 25 code?
Listed for the Infinity 24ANB7 two-stage air conditioner and the 25HNB6 and 25HNB9 two-stage heat pumps.
Can I fix Carrier 25 myself?
Only the basic checks. You can safely try the steps above, but 25 usually points to a part or fault that needs a technician.
Other Carrier air conditioner codes
- Solid / 1 / 2Status light showing normal operation
- 16Lost communication with the Infinity control
- 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
- P3Too cold outside to heat
- 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.