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Goodman gas furnace 3 red flashes: Pressure switch not closing

Gas furnace, Canada and United States

The inducer is running but the pressure switch does not close, so the burners do not light. The inducer keeps running with no further furnace operation.

This needs a licensed gas technician. There are a few safe checks you can do first, marked below. Anything inside the unit is a job for a professional.

This involves the flue or exhaust. A blocked or leaking flue can let carbon monoxide into the home.

What causes it

GMS8, GMH8, GMSS9, GMH95 and GKS9 boards

  1. The pressure switch hose is blocked, pinched or connected wrongly.

    Book a licensed gas technician

  2. The flue, chimney or (on high-efficiency models) the combustion air pipe is blocked, or the inducer is weak.

    Book a licensed gas technician

  3. On GMSS9, GMH95 and GKS9 condensing furnaces, the condensate drain system is blocked. The drain and trap are serviced by a qualified servicer.

    Book a licensed gas technician

  4. The pressure switch has the wrong setpoint or its contacts are faulty.

    Book a licensed gas technician

  5. Loose or wrongly connected wiring.

    Book a licensed gas technician

  6. On GMS8, GMH8, GDS8 and GDH8 furnaces fitted with a masonry vent kit, the kit's manual reset limit switch has opened, or the masonry chimney or flue is blocked.

    Book a licensed gas technician

GMES80, GMES92 and GMES96 boards

  1. The pressure switch hose is blocked, pinched or connected wrongly.

    Book a licensed gas technician

  2. The flue is blocked or the inducer is weak.

    Book a licensed gas technician

  3. The pressure switch has the wrong setpoint or its contacts are faulty.

    Book a licensed gas technician

  4. Loose or wrongly connected wiring.

    Book a licensed gas technician

GMEC96 three-colour light

  1. A faulty pressure switch.

    Book a licensed gas technician

  2. A problem with the pressure switch tubing, wiring or connections.

    Book a licensed gas technician

  3. The inducer relay on the control board has failed.

    Book a licensed gas technician

  4. The vent or intake pipe is blocked or restricted, for example at the outside termination, or has too many elbows or too much length.

    Check the outside flue or vent terminal is clearYou can do this

    1. Find where the flue or vent pipe ends outside the building. High-efficiency furnaces and some water heaters also have a combustion air intake pipe beside it: check that one too. On some outdoor water heaters the flue outlet is part of the front cover.
    2. Look for anything blocking it, such as leaves, a bird or insect nest, snow, plants, or items stored against the wall.
    3. Cut back plants and move stored items away from it. Do not touch, poke into or hose the flue outlet. If something is inside it, book a service.
      The terminal can be hot. Do not climb onto the roof or use a ladder to reach it; if it is out of reach, book a technician.

    Book a licensed gas technician

How to read this code on your unit

Booking a licensed gas technician

Book a licensed gas technicianlicensed gas technician

  1. Turn the unit off and leave the covers on. Gas components must only be serviced by a licensed technician.
  2. Note the code, how often it appears, and the model and serial numbers from the rating label.
  3. Book a licensed gas technician and give them those details.

Models that show this code

250 models in 12 ranges
RangeModels
GDH8GDH80403AN, GDH80403AX, GDH80603AN, GDH80603AX, GDH80804BN, GDH80804BX, GDH81005CN, GDH81005CX
GDS8GDS80403AN, GDS80403AX, GDS80603AN, GDS80603AX, GDS80804BN, GDS80804BX, GDS81005CN, GDS81005CX
GKS9GKS90453BX, GKS90703BX, GKS90704CX, GKS90904CX, GKS90905DX, GKS91155DX
GMH8 / AMH8GMH80403AN, GMH80403AX, GMH80603AN, GMH80603AX, GMH80604BN, GMH80604BX, GMH80803BN, GMH80803BX, GMH80804BN, GMH80804BX, GMH80805CN, GMH80805CX, GMH81005CN, GMH81005CX, GMH81205DN, GMH81205DX, GMH81405DN, AMH80403AN, AMH80403AX, AMH80603AN, AMH80603AX, AMH80604BN, AMH80604BX, AMH80803BN, AMH80803BX, AMH80804BN, AMH80804BX, AMH80805CN, AMH80805CX, AMH81005CN, AMH81005CX, AMH81205DN, AMH81205DX, AMH81405DX
GMH95 / GCH95 / AMH95GMH950453BX, GMH950703BX, GMH950704CX, GMH950904CX, GMH950905CX, GMH950905DX, GMH951155DX, AMH950453BX, AMH950703BX, AMH950704CX, AMH950904CX, AMH950905CX, AMH950905DX, AMH951155DX, GCH950453BX, GCH950703BX, GCH950704CX, GCH950905DX
GMS8 / AMS8GMS80403AN, GMS80403AX, GMS80603AN, GMS80603AX, GMS80604BN, GMS80604BX, GMS80804BN, GMS80804BX, GMS80805CN, GMS80805CX, GMS81005CN, GMS81005CX, GMS81205DN, GMS81205DX, GMS81405DN, AMS80403AX, AMS80603AX, AMS80604BX, AMS80804BX, AMS80805CX, AMS81005CX, AMS81205DX, AMS81405DN
GMSS92 / GCSS92 / AMSS92GMSS920402BN, GMSS920403AN, GMSS920603BN, GMSS920803BN, GMSS920804CN, GMSS920805CN, GMSS921004CN, GMSS921005CN, GMSS921205DN, AMSS920402BN, AMSS920403AN, AMSS920603BN, AMSS920803BN, AMSS920804CN, AMSS920805CN, AMSS921004CN, AMSS921005CN, AMSS921205DN, GCSS920402BN, GCSS920603BN, GCSS920804CN, GCSS921005CN
GMSS96 / GCSS96 / AMSS96 / ACSS96GMSS960402BN, GMSS960403AN, GMSS960603BN, GMSS960803BN, GMSS960804CN, GMSS960805CN, GMSS961005CN, GMSS961205DN, AMSS960402BN, AMSS960403AN, AMSS960603BN, AMSS960803BN, AMSS960804CN, AMSS960805CN, AMSS961005CN, AMSS961205DN, GCSS960402BN, GCSS960603BN, GCSS960804CN, GCSS961005CN, GCSS961205DN, ACSS960402BN, ACSS960603BN, ACSS960804CN, ACSS961005CN, ACSS961205DN
GMES80 / GCES80 / AMES80 / ACES80GMES800403AN, GMES800403AX, GMES800603AN, GMES800603AX, GMES800603BN, GMES800603BX, GMES800604BN, GMES800604BX, GMES800803BN, GMES800803BX, GMES800804BN, GMES800804BX, GMES800804CN, GMES800804CX, GMES800805CN, GMES800805CX, GMES801005CN, GMES801005CX, GMES801205DN, AMES800403AX, AMES800603AX, AMES800603BN, AMES800604BX, AMES800803BX, AMES800804BX, AMES800804CX, AMES800805CX, AMES801005CX, AMES801205DX, GCES800403AN, GCES800403AX, GCES800603AN, GCES800603AX, GCES800804BN, GCES800804BX, GCES801005CN, GCES801005CX, ACES800403AN, ACES800403AX, ACES800603AN, ACES800603AX, ACES800804BX, ACES801005CX
GMES92GMES920403AN, GMES920603BN, GMES920803BN, GMES920804CN, GMES920805CN, GMES921004CN, GMES921005CN, GMES921205DN
GMES96 / GCES96 / AMES96 / ACES96GMES960403AN, GMES960603BN, GMES960803BN, GMES960804CN, GMES960805CN, GMES961005CN, GMES961205DN, AMES960403AN, AMES960603BN, AMES960803BN, AMES960804CN, AMES960805CN, AMES961005CN, AMES961205DN, GCES960403BN, GCES960603BN, GCES960804CN, GCES961005CN, GCES961205DN, ACES960403BN, ACES960603BN, ACES960804CN, ACES961005CN, ACES961205DN
GMEC96 / GCEC96 / AMEC96 / ACEC96GMEC960302BN, GMEC960303AN, GMEC960402BN, GMEC960403AN, GMEC960603AN, GMEC960603BN, GMEC960803BN, GMEC960804CN, GMEC961004CN, GMEC961005CN, GMEC961205DN, AMEC960302BN, AMEC960303AN, AMEC960402BN, AMEC960403AN, AMEC960603AN, AMEC960603BN, AMEC960803BN, AMEC960804CN, AMEC961004CN, AMEC961005CN, AMEC961205DN, GCEC960403BN, GCEC960603BN, GCEC960803BN, GCEC961005CN, ACEC960403BN, ACEC960603BN, ACEC960803BN, ACEC961005CN

Where this comes from

Checked against the manufacturer's manual on 13 October 2026.

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Other Goodman gas furnace codes

Code Meaning What you can do
E1 Low-stage pressure switch closed at start of heating Call a pro
E2 Low-stage pressure switch not closing Safe checks first, then a pro
E8 High-stage pressure switch closed at start of heating Call a pro
E9 High-stage pressure switch not closing Safe checks first, then a pro
EE1 Pressure switch closed at start of heating Call a pro
EE2 Pressure switch not closing Call a pro
EE8 High-stage pressure switch closed at start of heating Call a pro
EE9 High-stage pressure switch not closing Call a pro
2 red flashes Pressure switch closed when it should be open Call a pro
3 double red flashes High-stage pressure switch stuck open Call a pro
6 red flashes Overheat / flue or venting fault (depends on model) Depends on your model
12 red flashes Flue or venting fault / ignition failure (depends on model) Call a pro

See all flue or venting fault codes on gas furnaces across brands.