Goodman Furnace & AC Error Codes

Below is a complete list of Goodman furnace and air conditioner diagnostic error codes (also applies to Amana, Daikin). Each code includes what it means, safe DIY checks you can try, when to call a professional, and estimated repair costs.

How to Read Goodman Error Codes

Look through the sight glass on the furnace access panel to see the red diagnostic LED on the control board. Count the number of blinks before the LED pauses and repeats the pattern. A steady ON LED with no flashing means the system is in normal standby waiting for a heat call. Rapid continuous flashing indicates a specific fault. Match the flash count to the error code chart on the label inside the access panel.

LED Location: The red LED is located on the furnace control board, visible through the sight glass window on the lower access panel.

Code Format: Single-digit flash code: count the number of red LED flashes in each repeating sequence (e.g., 3 flashes, pause, 3 flashes = Code 3). LED on steady = normal standby. Continuous rapid flashing has a special meaning.

Safety Warning

2 emergency code(s) require immediate professional attention. 5 high-urgency code(s) should be addressed promptly. If you smell gas, hear unusual sounds, or see sparks, turn off the system and call a professional immediately.

Quick Navigation — 12 Error Codes

LED On (steady, not flashing) 1 Flash 2 Flashes 3 Flashes 4 Flashes 5 Flashes 6 Flashes 7 Flashes 8 Flashes 9 Flashes Continuous Rapid Flashing LED Off (no light)

Goodman LED On (steady, not flashing): Normal operation — no call for heat

Low Urgency

The LED is on continuously without flashing. The furnace is powered and in standby mode, waiting for the thermostat to request heat. This is the normal idle status.

Common Causes

  • Thermostat is not calling for heat (normal condition)
  • Room temperature is at or above the set point

DIY Troubleshooting Steps

  1. No action needed — this is a normal status
  2. If you expect heating, check your thermostat settings

Call a professional when: The furnace shows steady LED but does not respond when the thermostat calls for heat.

Goodman 1 Flash: Ignition failure / flame failure lockout

High Urgency

The furnace has entered a lockout after failing to ignite or after losing the flame signal during operation. This is the most common Goodman error code and usually means the flame sensor needs cleaning.

Estimated repair cost: $100 – $400

Common Causes

  • Dirty or corroded flame sensor (most common cause by far)
  • Failed or cracked hot surface igniter
  • Gas supply interruption (valve off, low gas pressure, empty propane tank)
  • Defective gas valve not opening

DIY Troubleshooting Steps

  1. Clean the flame sensor — turn off power, remove the single mounting screw, gently scrub the metal rod with fine steel wool or emery cloth until it is shiny, then reinstall
  2. Verify the gas supply is on — check the manual shut-off valve near the furnace
  3. Reset the furnace by turning power off for 30 seconds, then back on

Call a professional when: The lockout returns after cleaning the flame sensor and verifying gas supply. A technician can test the igniter, measure gas pressure, and check the gas valve.

Goodman 2 Flashes: Pressure switch stuck closed

Medium Urgency

The pressure switch circuit is in the closed position when it should be open. The control board detected the switch was already closed before the inducer motor started, indicating a possible short or stuck switch.

Estimated repair cost: $150 – $400

Common Causes

  • Defective pressure switch with welded or stuck contacts
  • Short circuit in the pressure switch wiring
  • Malfunctioning draft inducer creating residual vacuum
  • Water trapped in the pressure switch hose

DIY Troubleshooting Steps

  1. Inspect the small rubber hose connected to the pressure switch for trapped water — disconnect one end and blow it clear
  2. Try resetting the furnace by cycling power off for 30 seconds

Call a professional when: This code typically requires a technician to test and replace the pressure switch. The switch is a safety device that should never be bypassed.

Goodman 3 Flashes: Pressure switch stuck open

Medium Urgency

The pressure switch did not close when the inducer motor started. The inducer runs to create a draft for safe venting, and the pressure switch verifies this draft exists. If the switch stays open, the furnace cannot proceed to ignition.

Estimated repair cost: $150 – $500

Common Causes

  • Blocked exhaust or intake vent pipe (ice, snow, debris, animal nests)
  • Cracked, kinked, or disconnected pressure switch hose
  • Clogged condensate drain causing water backup into the inducer (high-efficiency models)
  • Weak or failing inducer motor not creating enough draft

DIY Troubleshooting Steps

  1. Check exhaust and intake pipes outside your home for blockages — clear any ice, snow, leaves, or debris
  2. Inspect the small rubber hose connecting the pressure switch to the inducer housing for cracks, kinks, or moisture
  3. Check the condensate drain for clogs on high-efficiency furnaces

Call a professional when: The vents are clear and hose is intact but the code persists. A technician needs to test the inducer motor speed, measure actual pressure, and test the switch.

Goodman 4 Flashes: High-limit switch open — furnace overheating

High Urgency

The high-temperature limit switch has opened because the furnace is overheating. The furnace is not getting enough airflow across the heat exchanger to carry away the heat being produced.

Estimated repair cost: $150 – $600

Common Causes

  • Dirty or clogged air filter (most common cause)
  • Blocked or closed supply and return air registers
  • Failed blower motor or bad capacitor preventing proper airflow
  • Dirty blower wheel coated with dust and debris

DIY Troubleshooting Steps

  1. Replace the air filter immediately — this is the number one cause of overheating on all furnace brands
  2. Make sure all supply and return vents are open and not blocked by furniture or curtains
  3. Listen for the blower fan during operation — it should be running at a steady speed

Call a professional when: The code returns after filter replacement and opening vents. The blower motor, capacitor, or blower wheel may need professional attention.

Goodman 5 Flashes: Flame sensed with gas valve off

Emergency

The flame sensor is detecting a flame even though the gas valve is commanded off and there should be no call for heat. This is a serious safety condition that could indicate gas is leaking past the gas valve.

Estimated repair cost: $250 – $700

Common Causes

  • Leaking gas valve allowing gas to pass when closed
  • Gas valve mechanically stuck in the open position
  • Defective flame sensor providing false flame readings
  • Residual flame or heat source near the sensor

DIY Troubleshooting Steps

  1. If you smell gas, evacuate the home immediately and call 911 or your gas company from outside
  2. Turn off the gas supply to the furnace at the manual shut-off valve and leave it off

Call a professional when: Always call a professional immediately. Do not operate the furnace until a licensed technician has inspected and repaired the gas valve. A leaking gas valve is a fire and explosion hazard.

Goodman 6 Flashes: Rollout switch open or power polarity issue

Emergency

The flame rollout switch has tripped, or the furnace is detecting reversed line voltage polarity. On some Goodman control boards, 6 flashes indicates a rollout condition (flames detected outside the burner area); on others, it indicates reversed AC power polarity. Check the label inside your access panel for your specific model.

Estimated repair cost: $100 – $1,500

Common Causes

  • Flame rollout — flames escaping the burner compartment (blocked vent, cracked heat exchanger)
  • Reversed 115V AC polarity (hot and neutral wires swapped)
  • Blocked exhaust vent causing combustion gas backup
  • Excessive gas pressure pushing flames out of the burner area

DIY Troubleshooting Steps

  1. Check the exhaust vent outside for blockages
  2. If you recently had electrical work done, contact the electrician
  3. Do NOT reset the rollout switch yourself — it trips for a critical safety reason

Call a professional when: Always call a professional. Flame rollout can indicate a cracked heat exchanger (carbon monoxide hazard). Reversed polarity is an electrical safety issue. Both require professional diagnosis.

Goodman 7 Flashes: Low flame signal

Medium Urgency

The flame sensor is detecting a flame but the signal is below the acceptable threshold. The flame is too weak or the sensor is too dirty to get a strong reading.

Estimated repair cost: $100 – $350

Common Causes

  • Dirty flame sensor coated with oxidation or carbon buildup
  • Low gas pressure resulting in a weak flame
  • Partially clogged burner orifices
  • Flame sensor positioned incorrectly in the flame path

DIY Troubleshooting Steps

  1. Clean the flame sensor — turn off power, remove the mounting screw, scrub the metal rod with fine steel wool until shiny, and reinstall
  2. Verify other gas appliances in the home are working properly (if they are also weak, you may have a gas pressure issue)

Call a professional when: Cleaning the flame sensor does not resolve the code. A technician can measure the microamp signal, check gas manifold pressure, and clean the burners.

Goodman 8 Flashes: Igniter circuit fault

High Urgency

The control board has detected a problem with the hot surface igniter circuit. The igniter may be shorted, open, or the control board relay may be faulty. Some Goodman service bulletins note this can also be caused by improper furnace grounding.

Estimated repair cost: $150 – $350

Common Causes

  • Cracked or broken hot surface igniter (open circuit)
  • Shorted igniter drawing excessive current
  • Faulty furnace ground connection
  • Defective control board igniter relay

DIY Troubleshooting Steps

  1. Visually inspect the igniter through the sight glass — if it looks cracked or broken, it needs replacement
  2. Check that the furnace ground wire is securely connected to both the furnace frame and the electrical panel ground

Call a professional when: This code requires a technician to test the igniter resistance and the control board. Igniter replacement is a relatively common and affordable repair.

Goodman 9 Flashes: High-stage pressure switch or rollout switch fault

High Urgency

On two-stage Goodman furnaces, the high-stage pressure switch has failed to close or the rollout switch has tripped during high-stage operation.

Estimated repair cost: $200 – $500

Common Causes

  • Restricted exhaust vent unable to handle high-stage combustion volume
  • Weak inducer motor struggling at high-stage demand
  • High-stage pressure switch out of calibration or failing
  • Heat exchanger restriction causing abnormal draft

DIY Troubleshooting Steps

  1. Check exhaust and intake vents for any partial blockages
  2. Make sure the furnace air filter is clean to ensure proper airflow

Call a professional when: This code requires professional diagnosis. Two-stage pressure and draft issues involve calibration and testing that requires specialized instruments.

Goodman Continuous Rapid Flashing: Line voltage polarity reversed

High Urgency

The LED is flashing continuously and rapidly without pausing, indicating the 115V AC line voltage polarity is reversed (hot and neutral wires are swapped).

Estimated repair cost: $100 – $250

Common Causes

  • Reversed wiring at the furnace junction box or disconnect
  • Outlet wired incorrectly
  • Recent electrical work that affected the furnace circuit

DIY Troubleshooting Steps

  1. If recent electrical work was performed, contact the electrician who did the work
  2. Do not attempt to rewire the furnace yourself

Call a professional when: Always call a licensed electrician or HVAC technician. Reversed polarity can damage the control board and is a safety hazard.

Goodman LED Off (no light): No power to the furnace

Medium Urgency

The LED is completely dark, indicating no power is reaching the control board.

Estimated repair cost: $0 – $300

Common Causes

  • Tripped circuit breaker
  • Furnace power switch turned off
  • Blown control board fuse
  • Damaged power wiring

DIY Troubleshooting Steps

  1. Check and reset the furnace circuit breaker at the electrical panel
  2. Verify the furnace power switch is in the ON position

Call a professional when: The breaker trips again or the LED remains off after confirming power is on.

Need Goodman Repair in Central Texas?

Texas Temp Masters provides expert HVAC repair for Goodman , Amana, Daikin, and all major brands in Killeen, Waco, Temple, and surrounding areas. Call (817) 704-0706 for fast, reliable service, or contact us online.

Error code information cross-referenced from manufacturer documentation, HVAC/appliance professional resources, and verified repair databases. Codes can vary by specific model and control board revision. Always verify against your unit's diagnostic label or owner's manual. Repair costs are estimates based on national averages. Last updated February 2026.

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