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Error code reference
Carrier HVAC Error Codes
11 error codes documented with diagnostic procedures.
Have your model number? Get codes specific to your unit.
16System communication fault25Invalid motor/model selection26Invalid heater size27Invalid outdoor unit size36Heater output not sensed when energized37Heater output sensed on when not energized41Blower motor fault44Motor communication fault45Control board has failed internal start-up tests and must be replaced.46Brownout condition53Outdoor air temperature sensor fault
Get the full diagnostic procedure for any code
Step-by-step tests, expected values, wiring diagram references, and verified part numbers.
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More Carrier error codes
Common questions
How do I find the error code on my Carrier HVAC?
Most Carrier hvacs show the code directly on the control panel display. If your model has no display, it can be read by entering diagnostic mode with the key sequence for your model. The full procedures include model-specific instructions for reading codes.
Are these codes specific to my model?
The codes here apply broadly to Carrier hvacs. Meanings and diagnostic steps can vary by model and production year, so enter your model number for model-specific information and procedures.
What do I do if my code is not listed?
Some codes are model-specific or only appear in diagnostic mode. Enter your model number to get codes specific to your unit, or contact us. We update the database continuously from manufacturer service documentation.
How much does it cost to access the full diagnostic procedures?
A 3-day pass is $9.95 one-time and gives full access to all brands, codes, and procedures. Monthly access is $29/month with unlimited access to everything including Max AI diagnostics.