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Trane E06: Voltage reversed polarity or bad grounding

Ref. TRANE-E06 · From the Trane furnace manual · Updated 2026-10-23

Status codeE06Trane
What it means

Voltage reversed polarity or bad grounding.

Call a profurnace
How it shows: 7-segment display alternates with mode: E06

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§1Likely causes

  • Incoming 120 VAC line and neutral reversed
  • Neutral/ground problem
  • Faulty earth or chassis ground

§2Safe DIY steps

  1. Techniciancorrect incoming wiring polarity
  2. Techniciancheck and correct ground connections; furnace must be on a dedicated circuit
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: line-voltage wiring must be corrected by a qualified person.

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§4Other Trane codes

E01Trane

Loss of the IRQ or other internal failures (internal furnace control error).

E04Trane

Open limit: main thermal limit, flame rollout switch, or reverse airflow switch.

E05Trane

Flame detected when it should not be present.

E08Trane

Low flame current, but still strong enough to allow operation.

E09Trane

Open inducer limit switch or condensate pressure switch.

E12Trane

Open fuse: the onboard 5 amp fuse is open or missing.