What causes Goodman Gas Furnace A06?

Normal operation: the blower is running and moving roughly 550 to 649 CFM, so the display shows A06 in rotation with the mode. Constant fan (fan-only) or low-stage heat, which Goodman sets as a percentage of the furnace's maximum CFM and which can land near 600 CFM. A cooling Tonnage menu setting that's lower than the outdoor unit's size (Goodman's table puts 1.5 tons at 600 CFM), common after a new install. A dirty or overly restrictive air filter, which Goodman calls the most common cause of poor heating or cooling performance. Closed supply registers or blocked return grilles that restrict airflow.

How do I fix Goodman Gas Furnace A06?

Watch the display for a full cycle. If it alternates between A06 and a mode readout and nothing starts with E, the furnace is reporting airflow, not an error. Note what the system is doing when A06 shows. Fan-only or low heat at around 600 CFM can be perfectly normal. Full cooling on a 3 ton or bigger system usually shows a higher A number. Check the air filter and replace it if it's dirty. Goodman says never to run the furnace without a filter. Open supply registers and make sure return grilles aren't blocked by furniture or rugs. If you're the installer or comfortable with the menus, Goodman's manual lets you change the constant fan percentage, gas heat airflow and cooling Tonnage settings with the board's push buttons or the CoolCloud HVAC phone app. Cooling airflow should usually be about 400 CFM per ton of the outdoor unit. If the display shows a code starting with E, that's a real alarm, so look up that code instead.

When should I call a pro for Goodman Gas Furnace A06?

The house doesn't heat or cool well and A06 shows during full cooling or high heat on a system that should be moving much more air. You don't know the outdoor unit's tonnage or how the furnace was set up, and want the airflow, temperature rise and static pressure checked. The A number jumps around or the blower sounds like it's surging. An E code appears along with the airflow readout.

Code: A06🔥 Goodman Gas Furnace

Goodman Furnace A06 Code: Blower Airflow Readout, Not an Error (Meaning, What to Check)

Reviewed 2026-10-25 · Based on 2 manufacturer & service sources

What the code means

Goodman's variable-speed furnaces with the three-character seven-segment display (the service manual for the *MVS96*U family describes it; independent technician sites list the same readout on the GMVC96, GCVC96, AMVC96 and ACVC96 ComfortBridge furnaces) rotate a Status Menu: the operating mode, blower CFM if the blower is running, humidify or dehumidify mode, ventilator operation, and any active fault. Each item shows for 2 seconds, goes dark for 1 second, then the next one appears. Under Airflow Display, Goodman says the first character shows A, and the second and third show the actual CFM divided by 100, rounded to the nearest 100 CFM: 550 to 649 CFM displays as A06, and 1150 to 1249 CFM displays as A12. Under Alarm Display, Goodman says an active alarm shows in the Status Menu starting with E and a two-digit alarm code, so A-numbers are never alarms. Every fan mode is set as a percentage of the furnace's maximum CFM (1400 on 3 ton, 1760 on 4 ton and 2200 on 5 ton models in that manual), and with a non-communicating air conditioner or heat pump the cooling airflow comes from the Tonnage menu at 400 CFM per ton, with the manual noting most systems want 350 to 450 CFM per ton. A tonnage selection of 1.5 gives 600 CFM, which is exactly what A06 shows. So if you see A06 while the air conditioner on a bigger system is running, the tonnage or airflow setting is worth a look.

Likely causes

Normal operation: the blower is running and moving roughly 550 to 649 CFM, so the display shows A06 in rotation with the mode
Constant fan (fan-only) or low-stage heat, which Goodman sets as a percentage of the furnace's maximum CFM and which can land near 600 CFM
A cooling Tonnage menu setting that's lower than the outdoor unit's size (Goodman's table puts 1.5 tons at 600 CFM), common after a new install
A dirty or overly restrictive air filter, which Goodman calls the most common cause of poor heating or cooling performance
Closed supply registers or blocked return grilles that restrict airflow

Safe DIY checks

⚠ Before you start

Turn off power at the furnace/HVAC service switch and the breaker before opening panels. Shut the gas valve before any work near the burners, and never disconnect or alter the gas line. If you smell gas, leave the house and call your gas utility.

Watch the display for a full cycle. If it alternates between A06 and a mode readout and nothing starts with E, the furnace is reporting airflow, not an error.
Note what the system is doing when A06 shows. Fan-only or low heat at around 600 CFM can be perfectly normal. Full cooling on a 3 ton or bigger system usually shows a higher A number.
Check the air filter and replace it if it's dirty. Goodman says never to run the furnace without a filter.
Open supply registers and make sure return grilles aren't blocked by furniture or rugs.
If you're the installer or comfortable with the menus, Goodman's manual lets you change the constant fan percentage, gas heat airflow and cooling Tonnage settings with the board's push buttons or the CoolCloud HVAC phone app. Cooling airflow should usually be about 400 CFM per ton of the outdoor unit.
If the display shows a code starting with E, that's a real alarm, so look up that code instead.

🛠 When to call a pro

The house doesn't heat or cool well and A06 shows during full cooling or high heat on a system that should be moving much more air.
You don't know the outdoor unit's tonnage or how the furnace was set up, and want the airflow, temperature rise and static pressure checked.
The A number jumps around or the blower sounds like it's surging.
An E code appears along with the airflow readout.

Parts that commonly fix it

Always match the part number to your exact model.

⚙

Furnace air filter

Match the size printed on your current filter. A clogged filter is the first thing to rule out when airflow seems low.

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Sources

Last reviewed 2026-10-25. Always confirm against the manual for your exact model number.