9-FLASH
Goodman · GMVM970803BN 80,000 BTU 97% AFUE Modulating Gas Furnace with Variable-Speed ECM Blower
The 120VAC power supply wiring has reversed hot and neutral conductors, or the equipment ground is missing or has high impedance — this affects flame sensing (which uses the ground path as a reference) and causes nuisance lockouts; the furnace requires proper polarity and a solid equipment ground; verify with multimeter at the furnace disconnect
Error 9-FLASH on the Goodman GMVM970803BN 80,000 BTU 97% AFUE Modulating Gas Furnace with Variable-Speed ECM Blower means: Reversed Line Voltage Polarity / Ground Fault. The top-ranked community fix is “Use a Multimeter to Verify Line Voltage Polarity and Ground Integrity and Repair Wiring” (medium difficulty, ~45 min, DIY cost: $10-$20). 2 community-ranked fixes available below.
Published February 2026 · 2 fixes · furnace
Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.
While many furnace repairs can be done safely at home, consider hiring a qualified technician if:
Average professional repair cost for this issue: $150-$250.
Incorrect Blower Speed / DIP Switch Configuration
Communication Error — ComfortNet Bus
Blower Motor Fault (ECM)
Outdoor Ambient Sensor Fault
System Lockout — Retry Limit Exceeded
Pressure Switch Stuck Closed
Pressure Switch Did Not Close
High Limit Switch Open
The Goodman GMVM970803BN 80,000 BTU 97% AFUE Modulating Gas Furnace with Variable-Speed ECM Blower has 8 other known error codes:
Error code 9-FLASH also appears on 2 other Goodman models:
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