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Error code reference

Coleman Furnace Error Codes

7 error codes documented with diagnostic procedures.

Have your model number? Get codes specific to your unit.
1 FLASHIgnition failure.2 FLASHCombustion air pressure switch closed; the normally open pressure switch contacts are…3 FLASHCombustion air pressure switch failed to close; the normally open pressure switch contact…4 FLASHLimit switch open; a primary or auxiliary limit switch has opened its normally closed…5 FLASHGas flow detected with no call for heat.RAPID FLASHESReverse line voltage polarity detected; both heating and cooling will be affected.STEADY ONNormal operation; if the LED stays on continuously during a fault condition, it indicates…

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Step-by-step tests, expected values, wiring diagram references, and verified part numbers.

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Common questions

How do I find the error code on my Coleman Furnace?
Most Coleman furnaces 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 Coleman furnaces. 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.