Normal operation: gas furnace codes by brand

The light or display is reporting normal operation or a status message, not a fault.

Brand	Code	Meaning	What you can do
Carrier	11	No previous fault stored	You can often fix it
Goodman	IdL	Idle, normal operation	You can often fix it
Goodman	1 amber flash	Low-stage heat call	You can often fix it
Goodman	2 amber flashes	High-stage or single-stage heat call	You can often fix it
Carrier	steady amber light	Normal, the control has power and no fault to show	You can often fix it
Goodman	1 green flash	Low-stage cooling call	You can often fix it
Goodman	2 green flashes	High-stage or single-stage cooling call	You can often fix it
Goodman	green light flashing rapidly	Fan-only call	You can often fix it
Goodman	steady green light	Standby, waiting for a call	You can often fix it
Goodman	steady red light	Normal operation or control board internal fault (depends on model)	Depends on your model
Goodman	On	Normal operation	You can often fix it