6 flashesGoodman, Amana · GMSS9 / GCSS9 · Furnace

Goodman, Amana GMSS9 / GCSS9 error code 6 flashes

Rollout limit open or control module fuse blown

Goodman is the platform name, and your unit may not say it

Amana AMSS9 / ACSS9 is the same board with a different badge, so this page covers all of them. The fault, the checks and the parts are identical, which is why there is one page rather than one per brand.

Amana AMSS9 / ACSS9

Stop using it

Quick answer

On Goodman GMSS9 / GCSS9 (2000s), 6 flashes is a fault. It means rollout limit open or control module fuse blown. A first thing to check: Cracked or failed heat exchanger.

Applies to: Goodman GMSS9 / GCSS9; Goodman and Amana GMSS9, GCSS9, AMSS9, ACSS9 flash codes · Furnace · 2000s
Type of code: Fault; Urgency: Stop using it
First safe check: Note where the unit is installed. Rollout faults on units in closets, attics or utility rooms are far more common.

Checked 2026-09-26

What 6 flashes means on this model

Two different faults land on six flashes on this control. If the burner area has been running hot, it is the rollout limit switch opening. If the unit is completely dead, no blower and no display, it is the control module fuse. The distinction is easy to make and it decides the whole repair.

Symptoms you will notice

Furnace will not fire
Code appears shortly after the burner lights
Burner area or cabinet feels unusually hot
Musty or chemical smell near the furnace

Common causes

The code tells you what the control detected, not which part failed. These are the causes we see most often, roughly in order of likelihood:

Cracked or failed heat exchanger
Rollout switch failed closed or out of calibration
Burner assembly misaligned so flame licks past the heat exchanger
Combustion air problem causing incomplete burn
Blocked or disconnected flue

What you can safely check

These are homeowner-level checks. None of them need you to open a live electrical compartment or work on gas.

Note where the unit is installed. Rollout faults on units in closets, attics or utility rooms are far more common.
Look at the vent pipe inside the cabinet for a crack, a gap, or disconnected joint.
Confirm the burner assembly is fully seated and that the gasketing is intact.

Do not do these

×Do not bypass or hold down the rollout switch. It is detecting a genuine fire hazard.
×Do not run the furnace if you smell gas or notice a chemical smell in the cabinet.
×Do not attempt to repair a heat exchanger.

When to call a technician

Stop using the appliance and call today

This one is a safety limit, not a nuisance. The control is shutting the unit down to prevent damage or a hazard, and it will keep doing that until the underlying cause is fixed. Running it anyway risks the expensive failure it was designed to prevent.

This is a fuel-burning appliance, so treat anything involving a burner, gas valve or flue as technician work. If you smell gas at any point, leave the property and call the gas utility from outside rather than continuing to diagnose.
If the appliance has stopped mid-cycle, is making a noise you have not heard before, or smells burnt, stop reading here and call. Those are symptoms of something the fault code does not describe well enough.

Not a homeowner repair. Any rollout fault is a call to a licensed technician.

What it costs to fix

Parts

Heat exchanger assembly $400 to $1,200 depending on model. Rollout switch $20 to $50. Burner assembly $150 to $400.

Labor

Half a day or more, and on a cracked heat exchanger it is usually a replace-the-unit conversation.

DIY or technician