Goodman Error Code E0 indicates Furnace lockout due to an excessive number of ignition retries (3 total). Start by checking the most common and safe items identified in the troubleshooting section. If the code returns after those checks, professional diagnosis is recommended.
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Furnace lockout due to an excessive number of ignition retries (3 total)
Furnace fails to operate; LED displays E0 and ComfortNet thermostat shows ‘Check Furnace’
Failure to establish flame or loss of flame after establishment due to no gas, pressure switch stuck open, bad igniter/alignment, improper orifices, coated or improperly connected flame sensor, interrupted gas supply or lazy burner flame
Locate and correct gas interruption; check front‑cover pressure switch operation (hose, wiring); replace or realign igniter; clean flame sensor; inspect flue piping for blockage and verify induced‑draft blower performance; turn power off before repair
Gas supply, front‑cover pressure switch, igniter, flame sensor, flue piping, induced‑draft blower
Call an HVAC technician if the error persists after completing the recommended basic troubleshooting steps or if the system repeatedly locks out.
Disconnect power before inspecting the equipment. Never bypass safety devices or operate the system if you suspect unsafe conditions.
Learn more about the furnace components and operating conditions commonly associated with diagnostic error codes: