ErrorCodePro · Appliance Error CodesTrane Furnace Error Codes: Full List & Meanings
Every Trane furnace error code we have verified against Trane's own support pages, with its official meaning. This list covers s8b1, s8x1 and s8x2 gas furnaces (seven-segment display). Codes vary by model, so confirm in your owner's manual. Support: Trane dealer (trane.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 Trane 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 |
|---|---|---|---|
| E04 | The thermal limit is open: overheating, usually from restricted airflow. | Heating | Owner checks |
| E3.2 | The first-stage pressure switch is open when it should be closed. Venting, tubing or the inducer can cause it. Also: E3.4 | Venting / airflow | Owner checks |
| E2.1 | Ignition retries were exceeded without flame. Also: E2.2 | Heating | Owner checks |
| E01 | The manufacturer lists E01 as: internal failure. A licensed HVAC technician must diagnose this. | Control / electronics | Service |
| E2.3 | The manufacturer lists E2.3 as: 1st stage gas valve energized when it should not be. A licensed HVAC technician must diagnose this. | Heating | Service |
| E3.1 | The manufacturer lists E3.1 as: shorted pressure switch, 1st stage. A licensed HVAC technician must diagnose this. Also: E3.3 | Control / electronics | Service |
| E05 | The manufacturer lists E05 as: flame detected when it should not be present (shut off gas and call a technician). A licensed HVAC technician must diagnose this. | Heating | Service |
| E6.1 | The manufacturer lists E6.1 as: reversed polarity (high voltage). A licensed HVAC technician must diagnose this. | Power supply | Service |
| E6.2 | The manufacturer lists E6.2 as: faulty ground. A licensed HVAC technician must diagnose this. | Power supply | Service |
| E6.3 | The manufacturer lists E6.3 as: igniter circuit. A licensed HVAC technician must diagnose this. | Control / electronics | Service |
| E07 | The manufacturer lists E07 as: 1st stage gas valve energized when it should not be. A licensed HVAC technician must diagnose this. | Heating | Service |
| E08 | The manufacturer lists E08 as: flame current low (operation allowed). A licensed HVAC technician must diagnose this. | Sensors | Service |
| E12 | The manufacturer lists E12 as: open fuse. A licensed HVAC technician must diagnose this. | Power supply | Service |
Symptoms
Sources
Last reviewed: October 20, 2026. ErrorCodePro is not affiliated with Trane.