9 flashesGoodman, Amana, Daikin · GMV / GMH / GMS / GMN · Furnace

Goodman, Amana, Daikin GMV / GMH / GMS / GMN error code 9 flashes

High stage pressure switch stuck open

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

Amana AMV / GCH / GDS, Daikin GMV / GMH / GMS / GMN platform are 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.

Needs attention soon

Also written as 9 blinks

Which models this applies to. Applies to GMV8 / GMV9 only. This is the high stage pressure switch code, and the two-stage GMV is the series that reports it, so an eight-flash ceiling elsewhere in this group means you are looking at a different controller.

Quick answer

On Goodman GMV / GMH / GMS / GMN (1990s-2000s), 9 flashes is a fault. It means high stage pressure switch stuck open. A first thing to check: High stage pressure switch or its tube fault.

Applies to: Goodman GMV / GMH / GMS / GMN; Goodman, Amana and Daikin legacy furnace flash codes (GMV, GMH, GMS, GMN series) · Furnace · 1990s-2000s
Type of code: Fault; Urgency: Needs attention soon
First safe check: Set the thermostat to heat and listen for the inducer to start.

Checked 2026-09-26

What 9 flashes means on this model

On a two stage furnace the second stage of gas heat is not proving draft. The control started the inducer for high stage, never got pressure switch confirmation, and shut down. The furnace may still make heat on low stage, which is why this often shows up as weak heat rather than no heat.

Symptoms you will notice

Weak heat, or heat only on the first stage
Furnace runs but never reaches full capacity
Code appears on a call for high stage heat
Longer run time than the same house used to need

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:

High stage pressure switch or its tube fault
Inducer motor not moving enough air on the high stage setting
Blocked or restricted flue
Failing inducer capacitor
Control board high stage relay fault

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.

Set the thermostat to heat and listen for the inducer to start.
Inspect the high stage pressure tube for cracks, kinks and water.
Check the vent pipe outside for obstructions.

Do not do these

×Do not bypass the pressure switch.
×Do not run a furnace that will not reach full capacity as a permanent workaround. Low stage alone will not keep a cold house warm in a hard winter.

When to call a technician

Book a technician, do not keep resetting it

This fault will not clear on its own. Every power cycle gives the control one more failed attempt, and repeated attempts are what turn a cheap part replacement into a seized or contaminated system.

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.

Tube inspection and vent checks are fine. A failed pressure switch or board is technician work.

What it costs to fix

Parts

Pressure switch $30 to $90. Inducer capacitor $15 to $40. Inducer motor $150 to $400.

Labor

One to two hours.

DIY or technician