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Goodman · Furnace

EE6 Low flame signal

Low severity Goodman/Amana GM9S96/AM9S96Goodman/Amana GM9S80/AM9S80Goodman/Amana GM9C96/AM9C96

What the control is telling you

The furnace runs normally but the flame-sense current is weak. If it keeps dropping the furnace will start losing flame and locking out.

Applies to: Goodman/Amana/GMC gas furnaces, 9-speed ECM, 7-segment control. Two-stage 96%: AC9C96, AM9C96, GC9C96, GM9C96. Single stage 80%: VC9S80, VM9S80, AC9S80, AM9S80, GC9S80, GM9S80. Single stage 92/96%: VC9S96, VM9S96, AC9S96, AM9S96, AM9S92, GC9S96, GM9S96, GM9S92

Likely causes

  • Flame sensor coated or oxidized
  • Flame sensor not positioned correctly in the flame
  • Lazy burner flame from wrong gas pressure or poor combustion air
  • Poor ground

Test and repair steps

  1. Put a DC microamp meter in series with the flame sensor wire and run a heat cycle: normal is 1 to 4 microamps.
  2. Clean the flame sensor with steel wool (an invisible coating acts as an insulator) and check that it sits in the flame.
  3. Check the burner flame it should be stable, soft and blue, not lifting or yellow.
  4. Compare manifold and inlet gas pressure with the rating plate and adjust if needed.
  5. Inspect the combustion air intake pipe is it blocked, and are its length, elbow count and termination correct?
  6. Check high-resistance connections and grounding in the flame sense circuit.

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Source: Goodman RS6612022r1 (GM9S92/GM9S96/GC9S96 service), 1 Stage Troubleshooting Codes, p.29-30; Goodman RS6621008r2 (GM9S80 service), p.32-33; Goodman RS6612020r1 (GM9C96 service), 2 Stage Troubleshooting Codes, p.35-36; Checking Flame Sensor p.25-26 (RS6612022r1). Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.