LG Dryer Error Code d90 — 90% Exhaust Restriction
What this means
The d90 error code indicates the LG dryer's Flow Sense system has detected that the exhaust vent is approximately 90% blocked. This is a critical restriction that dramatically increases drying times, wastes energy, and presents a significant fire risk. Immediate vent cleaning is required.
Step-by-step fix
4 stepsStop using the dryer immediately
Do not run the dryer again until the vent is cleaned. A 90% restriction means exhaust heat has almost nowhere to go, which can ignite lint buildup inside the vent duct.
Lint is extremely flammable. Dryer vent fires cause an estimated 2,900 house fires per year in the US.
Clean the lint filter thoroughly
Remove and clean the lint filter. Wash it with warm water and dish soap to remove any invisible film from fabric softener or dryer sheets that reduces airflow through the mesh.
Disconnect and deep-clean the vent duct
Pull the dryer away from the wall. Disconnect the vent duct from the dryer and from the wall opening. Use a long vent cleaning brush kit to thoroughly clean lint from the entire duct run, working from both ends. Use a vacuum to remove loosened debris.
For long or complex duct runs, a rotary vent cleaning kit attached to a drill provides much more effective cleaning.
Clean the exterior vent and test
Clean the exterior vent hood and ensure the damper opens freely. Reconnect everything and run the dryer on Air Dry (no heat) for a few minutes. Go outside and hold your hand near the vent hood — you should feel strong airflow.
If airflow is still weak after cleaning, the duct may have a crushed section hidden inside the wall.
When to call a professional
At 90% blockage, strongly consider hiring a professional vent cleaning service, especially if the duct runs through walls, ceilings, or is longer than 15 feet. They can also inspect for crushed sections inside walls.
Related error codes
Information compiled from manufacturer service manuals, official troubleshooting documentation, and appliance repair industry resources. This guide is for informational purposes only — always consult a qualified technician for complex repairs.
Learn more about our sourcesParts you may need
Dryer Vent Cleaning Brush Kit (12-foot)
Part #Universal · $15–$30
Essential for vent cleaning
4-inch Rigid Metal Vent Duct
Part #Universal · $10–$20
If existing duct is vinyl, foil, or damaged
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