🔥Furnace

5-FLASH

Goodman · GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace

Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace 5-FLASH Error Fix: Flame Sensed Without Gas Valve Call

Flame is being detected by the flame sensor when the gas valve has not been commanded to open — this is a dangerous condition indicating a possible gas valve leak, stuck-open gas valve, or a false flame signal from a faulty flame sensor or contaminated flame rod; the system will lock out for safety

Medium severity2 fixes available✨ Free fix available

Quick Answer

Error 5-FLASH on the Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace means: Flame Sensed Without Gas Valve Call. The top-ranked community fix is “Test and Replace the Flame Sensor or Gas Valve” (hard difficulty, ~60 min, DIY cost: $10-$25). 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.

When to Call a Professional

While many furnace repairs can be done safely at home, consider hiring a qualified technician if:

The repair involves electrical wiring, gas lines, or refrigerant
You've tried the top-ranked fix and the error persists
You smell gas, see sparking, or notice water leaking
The repair requires specialized tools you don't have
Your appliance is still under manufacturer warranty

Average professional repair cost for this issue: $150-$250.

Other Goodman Models with Error 5-FLASH

GMVC960804CN 96% AFUE 80,000 BTU Two-Stage Gas Furnace

furnace · 2 fixes

GMVM970803BN 80,000 BTU 97% AFUE Modulating Gas Furnace with Variable-Speed ECM Blower

furnace · 2 fixes

Other Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace Error Codes

10-FLASH

Incorrect Blower Speed / DIP Switch Configuration

2 fixes

1-FLASH

System Lockout — Retry Limit Exceeded

2 fixes

2-FLASH

Pressure Switch Stuck Closed

2 fixes

3-FLASH

Pressure Switch Did Not Close

2 fixes

4-FLASH

High Limit Switch Open

2 fixes

6-FLASH

Flame Lost During Operation

2 fixes

7-FLASH

Ignition Lockout — Failed to Ignite

2 fixes

8-FLASH

Igniter Circuit Fault

2 fixes

People Also Ask About Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace Error 5-FLASH

What does error code 5-FLASH mean on a Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace?

Error code 5-FLASH on the Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace means: Flame Sensed Without Gas Valve Call. Flame is being detected by the flame sensor when the gas valve has not been commanded to open — this is a dangerous condition indicating a possible gas valve leak, stuck-open gas valve, or a false flame signal from a faulty flame sensor or contaminated flame rod; the system will lock out for safety

How do I fix error code 5-FLASH on my Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace?

The most successful fix is "Test and Replace the Flame Sensor or Gas Valve" (hard difficulty, ~60 minutes). Estimated DIY cost: $10-$25. HomeMD has 2 community-ranked fixes for this error.

Is error code 5-FLASH on a Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace serious?

This error is rated medium severity. It should be addressed soon, but your appliance may still function in a limited capacity.

Can I fix Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace error 5-FLASH myself?

Yes — the top-ranked community fix ("Test and Replace the Flame Sensor or Gas Valve") is rated hard difficulty and takes about 60 minutes. Tools needed: T20 Torx screwdriver, Multimeter, Gas leak detector.

How much does it cost to repair Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace error 5-FLASH?

DIY cost: $10-$25. Professional repair typically costs $150-$250. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace have?

The Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace has 8 other known error codes, including: 10-FLASH (Incorrect Blower Speed / DIP Switch Configuration), 1-FLASH (System Lockout — Retry Limit Exceeded), 2-FLASH (Pressure Switch Stuck Closed), 3-FLASH (Pressure Switch Did Not Close), 4-FLASH (High Limit Switch Open), and 3 more.

Which other Goodman models have the 5-FLASH error?

Error code 5-FLASH also appears on 2 other Goodman models: GMVC960804CN 96% AFUE 80,000 BTU Two-Stage Gas Furnace, GMVM970803BN 80,000 BTU 97% AFUE Modulating Gas Furnace with Variable-Speed ECM Blower. The fix may vary by model, so check each model's specific page for tailored repair steps.

What other error codes does the Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace have?

The Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace has 8 other known error codes:

10-FLASH — Incorrect Blower Speed / DIP Switch Configuration (2 fixes)
1-FLASH — System Lockout — Retry Limit Exceeded (2 fixes)
2-FLASH — Pressure Switch Stuck Closed (2 fixes)
3-FLASH — Pressure Switch Did Not Close (2 fixes)
4-FLASH — High Limit Switch Open (2 fixes)
6-FLASH — Flame Lost During Operation (2 fixes)
7-FLASH — Ignition Lockout — Failed to Ignite (2 fixes)
8-FLASH — Igniter Circuit Fault (2 fixes)

Which other Goodman models have the 5-FLASH error?

Error code 5-FLASH also appears on 2 other Goodman models:

GMVC960804CN 96% AFUE 80,000 BTU Two-Stage Gas Furnace (furnace) · 2 fixes
GMVM970803BN 80,000 BTU 97% AFUE Modulating Gas Furnace with Variable-Speed ECM Blower (furnace) · 2 fixes

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