Which models this covers
Goodman/Amana single-stage furnaces with LED boards, such as GMES80, GCES80 and GMSS92 (Goodman spec sheets). Two-stage boards (e.g. GMEC96) and newer 7-segment displays (GM9S80, GM9C96) use different codes. Codes differ between control boards, so check the code chart printed on your unit or in its manual if your model isn’t listed.
How to read the code
Look through the sight glass in the furnace door and count the LED flashes between pauses. Steady on means normal. Off means a control failure or no power. Rapid flashing means 115V polarity is reversed.
LED flash codes (single-stage boards)
Goodman’s spec sheets give the meaning only. The checks below are common starting points; anything involving gas, the inducer or the control board is a job for a pro.
| Code | What it means | What to do |
|---|---|---|
| Steady on | Normal operation | None. |
| Off | Control failure or no power | Check the furnace power switch and breaker. If power is on, call a pro.Pro |
| Rapid flash | 115V polarity reversed | Call a pro or electrician.Pro |
| 1 | System lockout (ignition retries exceeded) | Check that the gas is on, then reset power. If it repeats, call a pro.Pro |
| 2 | Pressure switch stuck closed | Call a pro.Pro |
| 3 | Pressure switch stuck open | Check outside vent pipes for snow, ice or blockage. If clear, call a pro.Pro |
| 4 | Open high limit | Replace a dirty filter and open closed vents. If it repeats, call a pro.Pro |
| 5 | Flame sensed without gas valve energized | Turn off the furnace and call a pro.Pro |
| 6 | Open rollout switch | Call a pro. Rollout can mean a blocked flue or cracked heat exchanger.Pro |
| 7 | Low flame signal | Call a pro. The flame sensor often needs cleaning.Pro |
| 8 | Check igniter or improper grounding (GMSS92) | Call a pro.Pro |
Sources
These codes are transcribed from the manufacturer’s own documentation. Many websites repeat codes that don’t match the manuals, so when in doubt, trust the chart on your unit.
- Goodman GMES80/GCES80 spec sheet
- Goodman GMSS92 spec sheet
- Goodman GMEC96 spec sheet (two-stage, different codes)
Code pointing to a big repair? Check whether to repair or replace before you pay for it.
Frequently asked questions
What does 1 blink mean on a Goodman furnace?
On Goodman single-stage boards, 1 flash means a system lockout because ignition failed too many times. It does not mean normal operation, as some sites claim. Check that the gas is on, then reset power. On two-stage boards like the GMEC96, 1 flash means something different (flame sensed when it shouldn’t be).
What does 3 blinks mean on a Goodman furnace?
Three flashes means the pressure switch is stuck open, so the furnace can’t prove the inducer is venting properly. Check the outside intake and exhaust pipes for snow, ice, nests or blockage. If they’re clear, call a pro.
What does 4 blinks mean on a Goodman furnace?
Four flashes means the high-limit switch is open: the furnace overheated. A dirty filter or closed supply vents are the usual causes. Replace the filter and open vents. If it continues, call a pro.