LG Dryer Error Code D90
Duct blockage detected — exhaust duct 90% blocked
The most common cause of the D90 error on a LG dryer is severe lint buildup in exhaust duct (~60% of cases); start with: stop using the dryer immediately.
What Does Error Code D90 Mean on a LG Dryer?
Duct blockage detected — exhaust duct 90% blocked.
The D90 code is generated by LG's Flow Sense system, which uses a duct sensor to gauge restriction in the exhaust path. When the control board calculates roughly 90% blockage, it interprets airflow as dangerously low and cuts or reduces heat to avoid overheating. Unlike D80, which warns of moderate restriction while allowing continued drying, D90 signals a critical condition. It differs from a heating or thermistor fault because the trigger is airflow-based, not element-based.
What Causes Error Code D90?
Here are the most common causes in order of frequency. Start with the most likely cause before moving to the next:
- 1 Severe lint buildup in exhaust duct 60% of cases
- 2 Duct completely kinked or crushed 20% of cases
- 3 Multiple blockages: lint filter + duct + exterior cap 15% of cases
- 4 Duct too long or too many bends causing low flow 5% of cases
How to Fix LG Dryer Error Code D90
- 1
Stop using the dryer immediately
A 90% blockage is a fire risk. Do not continue using the dryer until the duct is cleared.
⚠️ Fire hazard — stop all drying until resolved. - 2
Deep-clean the entire duct system
Clean the lint filter, the full length of the exhaust duct, the connection point at the dryer, and the exterior vent cap. Use a professional-length dryer vent brush.
🔩 Professional dryer vent brush kit ($20–$50) - 3
Check for duct damage
If the duct is made of flexible plastic or foil, it may have crushed inside a wall. Replace with rigid metal duct. Consider hiring a duct cleaning service for in-wall runs.
🔩 Rigid metal duct sections ($15–$40 each) - 4
Test airflow manually
After cleaning, hold your hand at the exterior vent while the dryer runs on Air Only. You should feel strong airflow.
How to Reset Error Code D90
After completely clearing all blockages, run the dryer on Air Only for 20–30 minutes. The D90 code will clear once adequate airflow is confirmed.
Note: If the error returns after resetting, the underlying issue has not been resolved. Work through the fix steps above.
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When to Call a Professional
If duct cleaning doesn't clear the code, the Flow Sense sensor may have failed, or you may need a professional duct cleaning service for complex wall-routed duct runs.
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Frequently Asked Questions
Can I keep using my LG Dryer when error D90 appears? +
What most commonly causes D90 on a LG Dryer? +
D90 keeps coming back after a reset — what should I check next? +
How much does it cost to fix LG Dryer error D90? +
Which LG Dryer models show error D90? +
Sources & References
- • LG Support — Help Library — official manufacturer documentation
- • Our editorial & verification policy
Content verified against manufacturer service documentation. Last verified: June 10, 2026.