Goodman GMSS920803BN Error Code 5 Flashes: Flame Sensed With No Call for Heat
What Does Code 5 Flashes Mean?
Five flashes on the Goodman GMSS920803BN diagnostic LED indicate that the Integrated Control Module is detecting flame when there is no active call for heat. As a safety response, the board runs both the induced-draft blower and the circulation blower continuously while keeping the furnace otherwise shut down.
The flame sensor proves a flame by passing a tiny electrical current through the burner flame to ground. This code means the board is reading that signal at a time when the gas valve is closed and no flame should exist. On this furnace that false reading almost always comes from a short to ground in the flame-sense circuit — a chafed or pinched sensor wire touching the metal chassis, or the sensor rod itself contacting a grounded surface — which mimics the current a real flame would produce.
This condition is the electrical opposite of the 7-flash low-flame-signal warning on the same board. Seven flashes means a genuine flame is producing too little current, while five flashes means the circuit is reporting flame current that is not real. Because both blowers keep running, the furnace is protecting itself rather than heating, and the false signal must be corrected before normal operation resumes.
What You'll Notice
- Both the inducer and the indoor circulation blower run continuously, often blowing unheated air, with no burner flame
- The furnace will not run a normal heat cycle even though the blowers are active
- The LED repeats a five-flash pattern
- There is no visible flame in the combustion chamber despite the running blowers
- The behavior may follow recent service, rodent activity, or vibration that could have chafed a wire
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Short to ground in flame sensor wiring | Most common | ✗ Call a pro → |
| Faulty flame sensor rod touching ground | Common | ✗ Call a pro → |
How This Is Diagnosed
A technician confirms the paradox at the heart of this code: the board is sensing flame current while the gas valve is closed. With power removed for safety, they inspect the flame-sensor wire along its full run for chafing, pinch points, or insulation damage where it could contact the grounded chassis, and they check that the sensor rod is not touching a grounded surface or a cracked porcelain insulator that would let it ground out.
If the wiring and rod position check out, the sensor and the flame-sense input at the control module are evaluated to determine whether the false signal originates in the sensor or the board. The repair is a wiring correction or component replacement in the flame-sense circuit, which is electrical service work, not a homeowner task.
When to Call a Professional
This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:
- The furnace runs both blowers continuously with the LED showing five flashes
- You see no flame in the combustion chamber but the blowers will not stop
- The flame-sensor wire looks chafed, pinched, or is touching the furnace body
- The code appeared after recent service, a rodent problem, or a component was moved
- Cycling power at the breaker does not clear the condition
Frequently Asked Questions
Why do both blowers on my Goodman GMSS920803BN keep running with a 5-flash code?
The board runs both blowers as a safety measure when it senses flame it did not command. It is trying to clear any combustion products and protect the system until the false flame signal — usually a wiring short to ground — is corrected.
Is a 5-flash 'flame sensed' code dangerous?
The code itself is the safety system reacting correctly to an impossible reading, and it keeps the burners off. The underlying wiring short should be diagnosed by a technician rather than ignored, since a compromised flame-sense circuit affects a core safety function.
Can I clear this by cleaning the flame sensor?
No. A 5-flash code is a short to ground in the flame-sense circuit, not a dirty rod producing a weak signal. It requires electrical inspection and repair of the wiring or sensor, which is a job for a qualified technician.
Sources
✓ Verified against manufacturer service manual — March 2026