Updated 2026-06-25
Frigidaire Furnace Error Codes & What They Mean
Compiled & reviewed by Nikolai Tsyrenov · Updated 2026-06-25
How do I read Frigidaire furnace error codes?
Frigidaire furnaces flash a fault code on a single red 'Status' LED on the integrated control board — count the number of flashes between pauses and match it to the legend printed inside the furnace door.
How to read Frigidaire furnace codes
Frigidaire furnaces flash a fault code on a single red 'Status' LED on the integrated control board — count the number of flashes between pauses and match it to the legend printed inside the furnace door. A separate yellow 'Flame' LED shows the flame-sense signal (solid = flame proven, flashing = a weak signal). The same Nortek/Nordyne board and codes are used across the sister brands Maytag (HVAC) and Gibson. The control doesn't store faults, so read the red LED before opening the lower door.
Frigidaire furnace code list
| Code | What it means (tap for fixes) |
|---|---|
| 1 flash | Limit circuit open — the over-temperature limit, flame-rollout, or vent-safety switch is open (often from restricted airflow), or there's an external load on the 'W' terminal. |
| 2 flashes | Pressure switch stuck open — after the inducer energized, the pressure switch did not close within about 10 seconds. |
| 3 flashes | Pressure switch stuck closed — at the start of the heat call the pressure switch was already closed (before the inducer started) and stayed closed. |
| 4 flashes | Ignition failure (check ground) — the control failed to prove flame after multiple trials (it tries 5 times) and locked out. It auto-resets and retries about hourly. |
| 5 flashes | Reversed polarity / poor ground — line hot and neutral are reversed, or the furnace lacks a proper earth ground. The furnace won't run until corrected. |
| Red Status LED steady on | Power on / normal — the control has power and detects no fault. If the furnace still isn't heating, check the thermostat and that the blower-door panel is fully closed (the door switch must be made). |
| Red Status LED continuous flash | False flame or shorted gas-valve relay — the control senses flame when none should be present, or the gas-valve relay is shorted. Reset main power or the thermostat; if it returns immediately, call a technician (don't run the furnace). |
| Red Status LED off | Power off — the control has no power. Check the breaker/disconnect, the blower-door switch, and the low-voltage fuse; if a board fuse keeps blowing, a technician must find the short. |
| Yellow Flame LED flashing | Low flame-sense signal — a weak flame signal (often a dirty flame sensor or poor ground), which usually precedes nuisance ignition lockouts. Have it serviced before it becomes a no-heat lockout. |
| Yellow Flame LED steady on | Flame present (normal) — the control is sensing a healthy flame during a heat cycle. Not a fault. |
⚠️ Safety first. Gas furnaces burn fuel and produce combustion gases. If you ever smell gas (a rotten-egg or sulfur odor), hear hissing, or your carbon-monoxide alarm sounds, do not touch light switches, thermostats, or the furnace — leave the home immediately and call your gas utility's emergency line or 911 from outside. Homeowners should limit themselves to simple, safe steps: setting the thermostat, checking and replacing the air filter, confirming the furnace switch and breaker are on, keeping supply registers and return grilles open, and clearing snow, ice, or debris from outdoor vent and intake terminations. Never bypass, jumper, or reset safety switches (limit, flame-rollout, or pressure switches), never open the gas valve or burner compartment, and never attempt combustion, electrical, or control-board repairs yourself. Error codes point toward a problem but are not a substitute for proper diagnosis — when in doubt, turn the system off and call a licensed HVAC technician. Keep working carbon-monoxide detectors on every level of your home.
Frigidaire furnace code FAQ
How do I read the error code on a Frigidaire furnace?
Frigidaire furnaces flash a fault code on a single red 'Status' LED on the integrated control board — count the number of flashes between pauses and match it to the legend printed inside the furnace door.
Where is the diagnostic light on a Frigidaire furnace?
It's on the control board, usually visible through a small sight glass on the lower blower-compartment door. You may need to remove the door panel to read it clearly.
What is the most common Frigidaire furnace code?
1 flash — Limit circuit open — the over-temperature limit, flame-rollout, or vent-safety switch is open (often from restricted airflow), or there's an external load on the 'W' terminal.
Other brands
Carrier furnace codesGoodman furnace codesTrane furnace codesLennox furnace codesRheem furnace codesYork furnace codes
Sources: graycoolingman.com. General information for homeowners — confirm against your furnace's installation manual.