Goodman GMEC96 furnace 4 red flashes: Open Limit Switch
Try DIY first, then call a pro
What do 4 red flashes mean on a Goodman GMEC96 furnace? The limit circuit opened because the furnace became too hot or a limit failed. The GMEC96 service manual says repeated limit openings can put the control into a one-hour lockout.
This condition involves the gas or combustion side. If you smell gas or a CO alarm sounds: leave, then call your gas utility. Diagnostic info here is reference — combustion repairs are for licensed technicians. All six emergency signs →
GOOD NEWS: THE FIRST CHECKS ARE FREE AND TAKE MINUTES.
Try these first — in this order
Install a clean filter, open every supply and return grille, and let the furnace cool before one restart.
If four flashes return, stop resetting it. A technician should measure temperature rise and airflow. DIY part cost: $5–25 — a pro visit for this class of fault typically runs $150–350.
What causes it (in order of likelihood)
- Dirty filter, closed registers, or restrictive ductwork DIY-CHECKABLE
- Weak blower, incorrect airflow setting, or failed limit TECH
Parts referenced by this code
Always match parts against your model's parts list — part numbers vary within a series.
Questions about this code
What do 4 red flashes mean on a Goodman GMEC96 furnace?
The limit circuit opened because the furnace became too hot or a limit failed. The GMEC96 service manual says repeated limit openings can put the control into a one-hour lockout.
How do I fix Goodman GMEC96 furnace 4 red flashes?
With the power off, replace an accessible filter with the same size and type and open every grille. If the code returns, stop resetting and call a technician to check airflow.
How much does it cost to fix Goodman GMEC96 furnace 4 red flashes?
A dirty filter or closed registers may cost little to correct. A weak blower, wrong airflow setting, or failed limit is a different repair, so the price depends on diagnosis.
Applies to
GMEC96
Different Goodman generations use different code maps. If your series isn't listed, don't assume this meaning — check your blower-door label.
Verified against Goodman GMEC96 Service Manual, p.53
Last verified 2026-07-06 · page updated 2026-10-03 · how we verify
Related Goodman furnace codes
These codes use the same gmec96 tri-color control — red fault flashes system.