ErrorCodePro · Appliance Error CodesGoodman Furnace Error Codes: Full List & Meanings
Every Goodman furnace error code we have verified against Goodman's own support pages, with its official meaning. This list covers gmss96/gcss96 gas furnaces (diagnostic led flash codes). Codes vary by model, so confirm in your owner's manual. Support: Goodman dealer or Goodman customer support (goodmanmfg.com).
Smell gas? Leave the building now. Do not touch light switches, phones or appliances inside. Call your gas utility or 911 from outside. CO alarm sounding or headache, dizziness or nausea? Get everyone outside and call 911. Gas valves, burners, venting and wiring are for a licensed technician only. See our safety policy.
Codes by system
Heating
Venting / airflow
All Goodman furnace error codes
Codes marked "Reset only" or "Service" have no separate page because the manufacturer publishes no owner fix beyond a reset or a service call.
| Code | Official meaning | System | Owner action |
|---|---|---|---|
| 4 flashes | The high limit switch is open: the furnace is overheating, usually from restricted airflow. | Heating | Owner checks |
| 3 flashes | The pressure switch stays open. Causes include a blocked vent or intake, a blocked condensate drain, or an inducer or switch fault. | Venting / airflow | Owner checks |
| 1 flash | The furnace locked out after too many ignition attempts. Causes include no gas to the burners, the igniter or a dirty flame sensor. | Heating | Owner checks |
| 2 flashes | The manufacturer lists 2 flashes as: pressure switch stuck closed. A licensed HVAC technician must diagnose this. | Control / electronics | Service |
| 5 flashes | The manufacturer lists 5 flashes as: flame sensed without gas valve energized (shut off gas and call a technician). A licensed HVAC technician must diagnose this. | Heating | Service |
| 6 flashes | The manufacturer lists 6 flashes as: open rollout switch (combustion/venting problem, CO risk). A licensed HVAC technician must diagnose this. | Heating | Service |
| 7 flashes | The manufacturer lists 7 flashes as: low flame signal. A licensed HVAC technician must diagnose this. | Sensors | Service |
| 8 flashes | The manufacturer lists 8 flashes as: check igniter or improper grounding. A licensed HVAC technician must diagnose this. | Control / electronics | Service |
| Rapid flashes | The manufacturer lists Rapid flashes as: reversed 115 VAC polarity. A licensed HVAC technician must diagnose this. | Power supply | Service |
| Steady off | LED off: control failure or no power. Check the service switch and breaker first. | Power supply | Service |
Symptoms
Sources
Last reviewed: October 20, 2026. ErrorCodePro is not affiliated with Goodman.