Goodman Furnace Error Codes: Complete Diagnostic List
16 diagnostic codes documented · Official site ↗
🟡 Warning — Schedule Service
System Lockout
Goodman's error code 1, or system lockout, indicates that your HVAC system has encountered an issue that it can't resolve on its own. This could be due to a variety of reasons, but it's important to note that this error won't cause immediate damage to your system or home. However, it's crucial to address this issue promptly to prevent further complications and ensure your system's longevity.
Pressure Switch Stuck Closed
Error code 2 on your Goodman HVAC unit indicates that the pressure switch is stuck in the closed position. This switch is designed to monitor the refrigerant pressure in your system and ensure it's within safe limits. When it gets stuck closed, it falsely signals that the pressure is too high, causing your system to shut down. This is a common issue with Goodman units and can usually be resolved by cycling the power or checking the switch itself.
Pressure Switch Stuck Open
Goodman's error code 3 indicates that the pressure switch is stuck open. This switch is crucial for monitoring and controlling the refrigerant pressure in your HVAC system. When it's stuck open, it can't accurately sense the pressure, leading to potential system issues. This is typically caused by a faulty switch or low refrigerant levels, which can cause the switch to open prematurely.
Open High Limit Switch
The Goodman 4 error, also known as an open high limit switch, indicates that your HVAC system has detected an issue with its high limit switch. This switch is designed to monitor the temperature of your system's heat exchanger and prevent it from overheating. When the switch is open, it can't perform its function, leading to potential system damage. This error is typically caused by a faulty switch, but it could also be due to a wiring issue or a problem with the system's temperature sensor.
Flame Sensed With Gas Valve Off
Error code 5 on your Goodman furnace indicates that the flame sensor is detecting a flame when the gas valve is supposed to be off. This could be due to a faulty flame sensor, a stuck gas valve, or a problem with the control board. It's important to address this issue to prevent potential system damage or safety hazards.
Open Rollout Switch
Goodman's error code 6 indicates that the system has detected an open rollout switch. This switch is part of the safety mechanism that allows the outdoor unit to communicate with the indoor unit. When the switch is open, it's as if the units are not talking to each other, causing the system to shut down. This could be due to a broken wire, a tripped safety switch, or a problem with the control board.
Low Flame Signal
The Goodman 7 error code indicates that your furnace's flame sensor isn't detecting a strong enough flame from the burner. This could be due to a dirty sensor, a faulty gas valve, or a problem with the ignition system. The system will typically go into lockout to prevent further operation and potential safety hazards.
Ignitor Error
When you see Goodman error code 8, it means your system's ignitor isn't working properly. The ignitor is responsible for creating a spark to light the burner in gas furnaces. This error is common in Goodman's NCB, NPE, and GPC series. It could be due to a faulty ignitor, a problem with the control board, or a wiring issue. Don't worry, your system is still safe to run in fan mode for cooling.
Goodman Code 9H - Soft Lockout
The 9H error code on your Goodman furnace indicates a 'soft lockout.' This happens when the furnace attempts to ignite, but fails to establish a stable flame within a set period. The furnace control board, acting as the 'brain' of the system, detects this failure and shuts down the gas supply as a safety measure. After a short waiting period, the control board will automatically attempt to restart the ignition sequence. Repeated soft lockouts suggest an underlying issue preventing successful ignition. While the furnace will try to restart itself, it's important to address the root cause to prevent further lockouts and potential damage to the system. Ignoring this issue could eventually lead to a complete shutdown of your heating system, especially during cold weather.
Reversed Polarity
The CONTINUOUS error code on your Goodman HVAC system indicates that there's a reversed polarity issue. This means that the positive and negative wires have been swapped, which can cause excessive current flow and heat, potentially damaging components. While this isn't an immediate safety risk like a gas leak, it's crucial to address this issue promptly to prevent further damage and system failure.
Goodman Code EAF - Airflow Error
The 'EAF' error code on your Goodman furnace indicates an Airflow Error. Your furnace's control board monitors the air pressure inside the unit using a pressure switch. If the furnace doesn't detect enough airflow when the blower motor is running, it assumes there's a blockage or a problem with the blower itself. To protect the furnace from overheating or other damage, it shuts down and displays the EAF error. This error is important because insufficient airflow can lead to the furnace overheating, which can damage components like the heat exchanger. A cracked heat exchanger can leak dangerous carbon monoxide into your home. While this code doesn't guarantee a cracked heat exchanger, it's important to address the airflow issue promptly to prevent further problems.
Goodman Code EE0 - Communication Error
The EE0 error code on your Goodman furnace or air handler indicates a communication problem between the main control board and other components, most often the blower motor. Think of it like a broken telephone line – the different parts of your system can't talk to each other. This prevents the unit from operating correctly, and it's why your system has shut down. The specific components involved can vary, but it always means the unit has detected a loss of communication on the data network.
Goodman Code F04 - High Limit Switch Open
The F04 error code on your Goodman furnace indicates that the high limit switch has tripped. This switch is a safety device designed to shut down the furnace if it gets too hot, preventing damage and potential fire hazards. When the furnace overheats, the high limit switch opens, cutting off power to the gas valve and blower motor. The furnace will then display the F04 error, indicating the problem. It's important to address this issue promptly, as repeated overheating can damage components and leave you without heat.
🔴 Critical — Shut Down Immediately
Goodman Code F01 - Ignition Lockout
The F01 error code on your Goodman furnace indicates an 'Ignition Lockout'. This means the furnace attempted to light the burners multiple times but failed. After several failed attempts, the furnace control board locks out the system as a safety measure. This lockout prevents the continuous flow of gas into the combustion chamber, which could create a dangerous situation. The system affected is primarily the gas ignition system, including the gas valve, igniter, flame sensor, and the furnace control board itself. A furnace that cannot ignite properly will not provide heat, and more importantly, could leak unburnt gas into your home.
Goodman Code F02 - Rollout Switch Open
The F02 error code on your Goodman furnace indicates that the rollout switch has tripped. This switch is a critical safety device designed to shut down the furnace if it detects flames where they shouldn't be – specifically, outside the normal combustion chamber. Rollout switches are manually reset, meaning they won't automatically allow the furnace to restart until the problem is fixed and the switch is physically reset. Ignoring this error can lead to fire or carbon monoxide poisoning, so it's important to address it immediately. When the rollout switch trips, it cuts off the gas supply to the burners, preventing further fuel from entering the system and exacerbating the problem. This is a fail-safe mechanism to protect your home and family. The F02 error code is a clear sign that something is seriously wrong with the combustion process, airflow, or venting of your furnace.