FixByModel
d90

LG d90: Exhaust duct about 90% blocked

The dryer detected roughly a 90% blockage in the exhaust ductwork, seriously restricting airflow. This is a safety concern, and LG advises not using the dryer until the vent is cleaned.

DIY fix

By the FixByModel editorial team · Verified 2026-09 · Researched against manufacturer support & repair references (below)

Most likely causes

  1. Heavy lint accumulation in the exhaust duct or vent
  2. Crushed, kinked, or excessively long ductwork with too many bends
  3. Blocked or damaged exterior vent hood
  4. Clogged lint filter
  5. Restricted transition duct behind the dryer
The airflow path — check in this order
1Lint filter
2Blower / lint housing
3Vent hose
4Wall duct
5Exterior vent

Schematic illustration of a typical dryer — not your exact model.

Before you start — unplug the dryer, and on a gas model shut off the gas supply. Let it cool first — the drum, heater and exhaust can be hot. If a step involves the heating element, wiring, or opening the cabinet and you're unsure, stop and call a qualified technician.

Step-by-step fix

1Stop using the dryerDo not keep running the dryer until the exhaust system is cleaned, as severe restriction is a fire hazard.
2Clean the lint filterCheck and clean the lint filter first, then confirm airflow at the outside vent while the dryer runs.
3Clear the full vent runUnplug the dryer and remove lint from the rear duct, the transition hose, and the vent all the way to the exterior.
4Inspect the vent hood and ductMake sure the outside vent hood is undamaged and opens freely, and replace crushed or kinked duct.
5Call a professional if neededIf the blockage persists or the run is long with many bends, have the venting professionally cleaned before further use.

Still showing d90?

If you’ve worked through every step and d90 keeps returning, an internal part likely needs testing and replacement. That’s a job for a qualified appliance technician, who can measure the suspect part against the service-manual spec before replacing it.

Which models this applies to

LG dryers. LG dryers with a duct-blockage flow sensor.

FAQ

What does LG d90 mean?

Exhaust duct about 90% blocked. The dryer detected roughly a 90% blockage in the exhaust ductwork, seriously restricting airflow. This is a safety concern, and LG advises not using the dryer until the vent is cleaned.

What causes LG d90?

The most likely cause is heavy lint accumulation in the exhaust duct or vent. Other causes include Crushed, kinked, or excessively long ductwork with too many bends; Blocked or damaged exterior vent hood; Clogged lint filter; Restricted transition duct behind the dryer.

Can I fix LG d90 myself?

Usually yes. Start by working through the steps above, beginning with: do not keep running the dryer until the exhaust system is cleaned, as severe restriction is a fire hazard.