Status codeE04Trane
What it means
Open limit: main thermal limit, flame rollout switch, or reverse airflow switch.
Basic checks firstfurnace
How it shows: 7-segment display alternates with mode: E04
§1Likely causes
- Dirty filters or blower wheel
- Blower motor not running
- External static pressure above nameplate (duct issues)
- Heat rise out of specification or outlet gas pressure out of specification
- Return air temperature too high
- Restricted flue piping or wrong LP orifices (rollout)
- Burner misalignment or flame impingement (rollout)
§2Safe DIY steps
- Turn off power and make sure the filter is clean
- Techniciancheck blower, static pressure, heat rise and gas pressure
- Technicianfor rollout, check flue, orifices, burners and heat exchanger before resetting rollout switches
- Never leave limit switches jumpered
Safety firstIf you smell gas, do not touch any electrical switch or use a phone in the building; leave immediately and call your gas supplier from outside. Turn off electrical power at the furnace switch or breaker before opening any panel, and never bypass or jumper a limit, rollout or pressure switch. Gas valve, burner, venting, wiring and control-board work should be done by a licensed HVAC technician.
§3When to call a pro
Call a licensed HVAC technician: if the code returns after a filter change, or a rollout switch has tripped.
Find a local HVAC pro →§4Other Trane codes
E01Trane
Loss of the IRQ or other internal failures (internal furnace control error).
E05TraneFlame detected when it should not be present.
E06TraneVoltage reversed polarity or bad grounding.
E08TraneLow flame current, but still strong enough to allow operation.
E09TraneOpen inducer limit switch or condensate pressure switch.
E12TraneOpen fuse: the onboard 5 amp fuse is open or missing.