Goodman Error Codes & Diagnostics
Complete diagnostic directory for official Goodman fault codes. Verify root causes, safe troubleshooting steps, and replacement part numbers before calling a technician.
Goodman GMVC one flash: external ignition lockout
On the documented Goodman GMVC80 control, one flash indicates external lockout after the furnace exceeds its ignition attempts. The control can automatically reset after one hour, while a thermostat or power interruption longer than five seconds can also reset it; none of those actions diagnoses why flame was not proved. Applies to: GMVC80 condensing gas furnaces This one-flash definition applies to the GMVC80 family in the cited Goodman installation instructions. Other Goodman boards use different LEDs and decimal codes, so identify the furnace and control before counting. Owner-safe checks: Keep furnace panels installed, record one full startup sequence and the repeating flash, and stop without creating additional ignition attempts. Qualified technician: Draft, vent, condensate, igniter, gas, burner, flame-current, grounding, safety, and control tests require licensed gas-furnace service.
Goodman two flashes: the pressure switch is closed when it should be open
Two flashes on a Goodman integrated control reports the pressure switch circuit closed at a point in the sequence where the control expects it open. The control checks the switch before the inducer runs, and a circuit already made at that moment means the switch cannot prove anything about draft once the inducer starts. Applies to: Goodman GMVC-series two-stage variable-speed gas furnaces documented in the installation and operating instructions Take this from the diagnostic table printed in the Goodman GMVC-series installation and operating instructions. Goodman has used other flash counts on earlier and later control platforms, and Amana equipment built on related controls publishes its own table. Take the count from the label inside your own furnace door. Owner-safe checks: Read the flash count through the door sight glass rather than removing the blower door, since opening it can cut control power and clear the code. | Confirm the thermostat is set to heat, is calling, and has good batteries if it uses them. | Look for standing water or staining around the base of the furnace and note anything you find without touching tubing or switches. Qualified technician: Testing a pressure switch, clearing condensate tubing, and inspecting the inducer and vent path are licensed gas-furnace tasks. | Never bridge, jumper, or bypass a pressure switch to make a furnace run. The switch is the only thing confirming that combustion products are leaving the building.
Goodman GMVC80 three flashes: pressure switch open after the inducer starts
On the documented Goodman GMVC80 board, three flashes means the pressure-switch circuit is open when the control expects it closed. It does not prove the pressure switch is defective. The inducer, venting, condensate path, hose, wiring, and available draft all remain part of the diagnosis. Applies to: Goodman GMVC80 condensing gas furnaces This three-flash definition belongs to the GMVC80 instructions cited here. Newer Goodman furnaces can use alphanumeric seven-segment codes instead of this LED pattern, so match the model and the legend on its door before applying the meaning. Owner-safe checks: Listen to one complete heat-call sequence with every furnace panel installed and record whether the inducer starts before the code. | Look at accessible outdoor intake and exhaust openings for visible snow, leaves, nests, or damage without inserting anything. | Photograph the flash pattern twice and capture the model number and door-chart wording before power is changed. Qualified technician: Pressure measurement, hose and condensate inspection, switch testing, vent assessment, and live electrical diagnosis require qualified gas-furnace service. | Never bypass a pressure switch or hold a panel interlock to force an ignition attempt.
Goodman furnace 4 flashes: open high-limit circuit
Four flashes on a Goodman furnace control means the primary limit circuit is open. The limit is a temperature safety that trips when the air leaving the heat exchanger is too hot, so the fault points at restricted airflow or poor heat transfer rather than at a failed switch. Applies to: Goodman and Amana single-stage and two-stage gas furnaces with an integrated ignition control This meaning applies to Goodman and Amana gas furnaces whose control legend lists four flashes as an open limit or open high-limit circuit. Flash-code meanings differ between control boards, so read the label inside the furnace blower door for the exact model. Owner-safe checks: With the furnace off, replace a loaded filter with the correct clean size, arrow pointing toward the blower, and confirm supply and return grilles are open and unblocked. | Note whether the four-flash code clears with airflow restored and whether it returns on the first or second heating stage. Qualified technician: Measuring temperature rise and static pressure, inspecting the blower motor, capacitor and wheel, and testing or replacing the limit switch are technician tasks, and the limit must not be bypassed.
Goodman five flashes: flame sensed when no flame should exist
Five flashes on a Goodman integrated control reports flame sensed when there was no call for heat and the gas valve should have been closed. The control is describing gas burning outside the sequence it commanded, which is why the response is to shut down and involve a licensed engineer rather than to reset and observe. Applies to: Goodman GMVC-series two-stage variable-speed gas furnaces documented in the installation and operating instructions What follows is scoped to GMVC-series equipment and the flash table Goodman prints for it. Other Goodman control generations, and related brands built on similar boards, assign this count differently, so the diagnostic label fixed inside your own furnace door is the authority rather than any chart found elsewhere. Owner-safe checks: Check for any smell of gas indoors, and if one is present leave the property and use the emergency number your gas supplier publishes before doing anything else. | Switch the furnace off at its dedicated service switch so the control stops attempting cycles. | Note whether you actually saw or heard burner activity, or whether only the code was present, and record the time. Qualified technician: A gas valve that does not seat, a burner alight outside its commanded sequence, and flame sensing circuit faults are licensed gas engineering work without exception. | Do not operate, reset, or test the furnace to see whether the code returns. The condition being reported is combustion the control did not ask for.
Goodman six flashes: a rollout trip and a wiring fault on one count
Six flashes is a count that Goodman has assigned differently on different integrated controls, including a flame rollout trip on some and a line voltage polarity or grounding condition on others. Because those two readings have completely different risk levels, the diagnostic label inside your own furnace door decides which one applies, not a chart found elsewhere. Applies to: Goodman GMVC-series and related integrated furnace controls documented in the installation and operating instructions Goodman publishes the flash-count table on the wiring and diagnostic label of each furnace and in that model's installation and operating instructions. The count-to-meaning mapping is a property of the control platform, so a table from a different Goodman generation, or from Amana equipment on a related control, can be wrong for your furnace. Owner-safe checks: Read the diagnostic label inside the furnace door through the sight glass or during a permitted access, and record what six flashes is assigned to on that control. | Look and smell for soot, scorching, or combustion odours around the furnace without opening the burner compartment. | List any electrical work, supply changes, or generator use in the period before the code appeared. Qualified technician: A flame rollout trip requires combustion, heat exchanger, and venting assessment by a licensed gas engineer, and the reset button on a rollout device is not an owner control. | Correcting line voltage polarity or a grounding fault at the furnace supply is electrical work for a qualified person, not a matter of swapping conductors on a guess.
Goodman furnace 7 flashes: weak flame sense signal
Seven flashes on a Goodman furnace control means the flame sense current has fallen below the level the board needs to confirm a flame. The burner lights, but the control does not read enough microamps of rectified current, so it closes the gas valve and retries, then locks out after a set number of trials. Applies to: Goodman and Amana gas furnaces with an integrated ignition control that flashes seven for low flame signal This meaning applies to Goodman and Amana furnaces whose control legend lists seven flashes as a weak or low flame signal. Boards differ, so a furnace showing seven flashes for a different fault should be read against the label inside its blower door. Owner-safe checks: Watch a start-up cycle and note that the burner does light before it drops out, and count how many attempts happen before the lockout. | Confirm the furnace door is fully closed and the filter is clean, then leave the panel in place for a technician to open. Qualified technician: Cleaning or replacing the flame sense rod, checking the burner ground, measuring flame current, and adjusting gas pressure all require a qualified heating technician working inside the furnace.
Goodman ComfortNet Eb0, Eb1 and Eb3 in cooling: why an airflow code appears while heating still works
Read them apart. The b3 entry is the only airflow condition of the three. Goodman describes it as the circulator blower motor operating in a power, temperature or speed limiting condition, and lists blocked filters, restrictive ductwork, undersized ductwork and high ambient temperature as the causes. The b0 entry says the motor is not running when it should be, and b1 says the control module has lost communication with the motor. Neither of those is a duct problem, and grouping all three sends the diagnosis to the wrong place. Applies to: Goodman and Amana variable-speed air handlers with an integrated control module reporting motor codes on a seven-segment display and through a ComfortNet thermostat These codes belong to the air handler integrated control module, and the seven-segment display alternates characters, which is why written transcriptions vary between readers. Furnace and outdoor unit codes on the same ComfortNet system come from separate tables. Owner-safe checks: Check the filter and replace or clean it according to the equipment instructions, because blocked filters are on the published cause list. | Confirm that supply registers and return grilles are fully open and unobstructed. | Record whether the code appears in cooling, in heating, or in both, and whether the blower ran at all. | Note how warm the space around the air handler gets, since high ambient temperature is listed as a cause of the limiting condition. Qualified technician: Any work on motor power leads, motor control leads or the integrated control module is inside an energised cabinet and is service work. | Duct static pressure measurement and duct sizing assessment need instruments and belong to a technician.