Goodman furnace 1 flash: ignition lockout (single-LED boards)

Furnace control display or LED

1 flash

“Furnace lockout due to an excessive number of ignition “retries” (3 total).”

GMES9* / GCES9* / AMES9* / ACES9* / VMES9* / VCES9*, GMES80 / GCES80 / AMES80 / ACES80 / VMES80 / VCES80, GMSS9* / GCSS9* / AMSS9* / ACSS9*, GKS9 / AKSS92, GMS8 / AMS8 / GDS8 / ADSS8, GMH8 / AMH8 / GDH8 / ADSH8, GMH95 / AMH95 / GCH95 / ACSH96, GME95 / AMEH96, GME8 / AMEH8 · IOG-2020J p. 40; IOG-2021H p. 29; IOG-2009Q p. 42; RS6612004R2 p. 49; RS6612006R7 p. 43; RS6612007R4 p. 41; RS6612003R2 p. 54; RS6612005R1 p. 49; RS6621001R2 p. 35
Owner checks, then technician

What it means

On Goodman and Amana furnaces with a single diagnostic LED, one flash between pauses is a lockout: the control tried to light the burners three times without success, and the furnace fails to operate RS6612012R8, p. 44. The GMSS9 table gives two kinds of cause RS6612012R8, p. 44:

The flame was never established: no gas to the burners, the front cover pressure switch stuck open, a bad or misaligned igniter, improper orifices, or a coated, oxidized or improperly connected flame sensor.
The flame was lost after it was established: an interrupted gas supply, lazy burner flames from improper gas pressure or a restriction in the flue or combustion air piping, the front cover pressure switch opening, or improper induced draft blower performance.

The GMES9 table lists the same two groups without the front cover pressure switch and the combustion air piping IOG-2020J, p. 40.

This meaning holds only for the single-LED series listed at the top of this page. On three-color boards one flash means something else, and on GMEC96 and GMEC80 boards one amber flash is normal operation (see the notes below).

Check these first

Count the flashes between pauses and write the number down. The owner’s manual has you read the LED through the blower compartment sight glass HIG-2002A, p. 8; the GMSS9 service manual calls it the observation window in the blower access door RS6612012, p. 31. If your LED flashes red, amber or green, use the notes below instead.
Reset the lockout by one of the three methods in the owner’s manual HIG-2002A, p. 6: wait for the control to reset itself after the one-hour lockout period; interrupt the 115 volt power to the furnace for more than 20 seconds; or interrupt the thermostat signal to the furnace for between 0 and 20 seconds.
If the condition that caused the lockout is still there, the control locks out again. If the furnace locks out often, the manual says a problem exists that must be corrected and to contact a qualified servicer HIG-2002A, p. 6.
If the LED keeps flashing, the troubleshooting section says to shut the furnace down and contact a qualified servicer HIG-2002A, p. 8. The shut-down: thermostat to its lowest setting, then, behind the burner compartment door, the gas valve’s ON/OFF switch to OFF, the external manual gas shut-off valve closed, and the door back on HIG-2002A, p. 6. Before the gas control goes to OFF, the start-up steps and the label also turn off the electrical power to the furnace; the label says to do so if service is to be performed HIG-2002A, pp. 6, 9. Move the gas control by hand only, never with tools HIG-2002A, p. 9. Full steps: shutting the furnace down.

Do not go further than this: “Do not attempt repairs yourself” HIG-2002A, p. 8, and “do not remove any internal compartment covers” HIG-2002A, p. 6.

When to call a licensed technician

The corrective actions in the GMSS9 table are technician work RS6612012R8, p. 44:

Locating and correcting a gas interruption.
Checking the front cover pressure switch: hose, wiring and contact operation.
Replacing or realigning the igniter. The table warns that the igniter is fragile.
Checking the flame sense signal and cleaning the flame sensor if it is coated or oxidized.
Checking the flue piping for blockage, proper length, elbows and termination, and the induced draft blower’s performance.

The same table says to turn power OFF before any repair RS6612012R8, p. 44. Call as well if the lockout comes back after a reset or happens often HIG-2002A, p. 6.

Notes for different models

Board or series	Code	Meaning in the table	Source
Single LED: GMES9, GMES80, GMSS9, GKS9, GMS8, GMH8, GMH95, GME95, GME8	1 flash	Lockout after 3 ignition retries	RS6612016, p. 43; IOG-2009Q, p. 42
GMS8, second table of the 2017 revision	1 flash	Lockout after 3 ignition attempts	RS6612006R7, p. 45
GMEC96, GMEC80	Red 1 flash	“Flame sensed when no flame should be present”	IOG-2011U, p. 54 (GMEC96); RS6621005R1, p. 28 (GMEC80)
GMEC96, GMEC80	Amber 1 flash	“Normal operation with low stage call for heat (W1)”	IOG-2011U, p. 54 (GMEC96); RS6621005R1, p. 28 (GMEC80)
GMEC96, GMEC80	Green 1 flash	“Normal operation with low stage call for cooling (Ylo & G)”	IOG-2011U, p. 54 (GMEC96); RS6621005R1, p. 28 (GMEC80)
MES96U, GMES80*U, 2019 manuals	Red 1 flash	Lockout after 3 ignition attempts	RS6612017, p. 20; RS6621006, p. 16
MES96U, GMES80*U, 2019 manuals	Amber 1 flash	“Low flame sense”	RS6612017, p. 21
MES96U, GMES80*U, 2019 manuals	Green 1 flash	“Call for heating.”	RS6612017, p. 21
Three-character display	EE0	Lockout after 3 ignition retries	IOG-2037D, p. 43

On GMEC96 and GMEC80 boards the ignition lockouts are red 7 and red 8 flashes GMEC96: IOG-2011U, p. 55; GMEC80: RS6621005R1, p. 29. Red 1 flash there is a technician item: the table points to a gas valve stuck open, improper wiring to the gas valve, or a shorted flame rod or wire, and asks for electrical and gas safe conditions before repairs GMEC96: IOG-2011U, p. 54; GMEC80: RS6621005R1, p. 28.

The GMEC96 service manual’s own lockout section says a lockout is characterized by “a one flash diagnostic LED code” RS6612013, p. 44, while its table lists the ignition lockouts as red 7 and red 8 flashes and red 1 flash as “Flame sensed when no flame should be present” RS6612013, pp. 42–43.

Older editions of the owner’s manual (HI-115C, 02/12; HIG-2002, 07/19) had one more check: that the manual gas shut-off valve outside the furnace is ON, and if it is OFF, turning the gas on by following the start-up steps HI-115C, p. 8; HIG-2002, p. 8. The current edition, HIG-2002A (09/19), no longer has this check HIG-2002A, p. 8, and this page does not recommend it. The start-up steps include a five-minute wait to clear out gas and a smell check near the floor; if you smell gas after that wait, the manual says to immediately follow the instructions on its cover HIG-2002A, p. 6.

The GMSS9 service manual gives its own reset times: the thermostat off for more than 5 and less than 20 seconds, or the disconnect off for at least 5 seconds RS6612012, p. 31. The owner’s manual gives more than 20 seconds for the power method HIG-2002A, p. 6. These pages follow the owner’s manual.