LG Dryer d90 Error
One step below the top of LG's Flow Sense scale (d75 · d80 · d90 · d95). Two or four bars on the Flow Sense indicator mean the same restriction in bar form.
What to check first
- Read the number: d90 means LG's Flow Sense estimates the exhaust is approximately 90% restricted — LG's immediate-attention level.
- Do not keep restarting against it: LG says the dryer shuts down to prevent overheating.
- Work LG's order: filter, hose behind the dryer, outside outlet, then the in-wall duct.
- Still showing → professional duct cleaning; note the duct length and elbow count.
A d90 code means LG's Flow Sense system estimates the dryer's exhaust is approximately 90% restricted. LG's Flow Sense guidance treats d90 (with d95) as the levels that prompt immediate attention: there is an issue with poor venting exhaust, causing the dryer to shut down to prevent it from overheating and becoming a fire hazard. LG calls these safety alerts, not malfunctions — but at 90% the margin the system was designed with is spent. The checks are the same vent path as d80, in LG's order, with less room to defer them.
Safety first
- Do not keep restarting the dryer to finish loads against a d90. LG's own framing is that the dryer shuts down to prevent overheating and a fire hazard — overriding that protection cycle after cycle is exactly the use the warning exists to stop.
- Work on the duct with the dryer unplugged where you are disconnecting anything, and never run the dryer with the exhaust hose detached indoors.
- Stop condition: stop using the machine and unplug it — and do not run it again until it has been checked — if you smell burning, see smoke, find damaged electrics (a scorched plug, a melted or cut cable), or water is leaking in quantity.
Common causes
Lint buildup in the exhaust system
A d90 warning may result from lint accumulation, a crushed hose, a blocked outlet, or restrictions elsewhere in the exhaust path. LG's first check for the family is lint buildup at the rear exhaust duct.
A crushed or kinked exhaust hose
LG's US list: a crushed or damaged exhaust duct will also cause air blockage. A crushed or damaged section behind the dryer can severely restrict airflow on its own — check it before paying to clean a long run.
Long runs and elbows hiding the blockage
LG warns that long duct runs or runs with multiple elbows create hard-to-trace blockages. At d90 the blockage may be deep in the wall run — which is why LG's sequence ends with a professional duct cleaner and two measurements (length, elbow count) that show whether the run itself is the problem.
Step-by-step checks
- Inside the dryer: clean the lint filterRemove lint from the lint tray between each load. Clean the tray with warm water and a soft brush, then allow it to dry before reinstalling. Reduce the load size to allow air to pass through from back to front. (LG UK's order.)
- Behind the dryer: check the exhaust hoseCheck that the exhaust hose between the dryer and the wall is not crushed, dented, kinked or compressed; verify it is not coiled circle over circle like a spring; confirm there are no holes in the hose and no loose connections. LG gives the same instruction for rigid, semi-rigid and flexible duct.
- Outside the home: check the exhaust outletLocate the exhaust outlet on the outside of your home — it may have flappers, a cage or mesh to block animals and debris. Verify the flappers can open all the way (they can jam with lint): run the Air Dry cycle once and you should see them fully opened. That one brief run is a check, not a restart strategy — it is not an instruction to repeatedly restart a dryer displaying a severe warning; if the dryer shuts itself down, leave it off and work the rest of the path with it unplugged. Remove any visible lint around the exhaust.
- Inside the walls: the hidden duct runIf steps 1–3 did not resolve the code, LG's endpoint is a dryer duct cleaner in your area to clean the vents located in your house. While they are on site, LG asks you to get two figures from them: the length of the ventilation system from the dryer to the outside exhaust, and the number of 90-degree angles within it — those determine whether the run itself needs modifying.
When to call a technician
LG's endpoint for d90 is a professional duct cleaning — at this level its guidance is a recommendation to call one, not a suggestion to wait for the yearly visit. An appliance technician enters only if the duct is proven clean and the code still posts (LG's Flow Sense guidance then raises a defective blower fan — an LG service case).
Quote the exact code — d90 — when you book, so the cleaner knows which Flow Sense warning appeared.
Model differences
| What you have | What changes |
|---|---|
| The dryer stops mid-cycle | Consistent with LG's Flow Sense guidance: poor venting causes the dryer to shut down to prevent overheating. The stop is the protection working, not a second fault. |
| Flow Sense bars instead of a number | Two or four bars lit mean the exhaust system is severely restricted (LG US) — treat bars at this level like d90/d95. |
| A brand-new installation | LG recommends the duct be cleaned when a new dryer is installed — a new, more sensitive dryer on an old duct is a classic d90 — and on new houses, check the wall vent end cap is not closed or blocked. |
One-page checklist — d90
- Code read as d90 (Flow Sense estimate: approximately 90% restricted — treat as immediate attention, per LG)
- Dryer not restarted repeatedly against the code
- Lint filter cleaned (warm water + soft brush, dried fully)
- Hose behind the dryer checked: not crushed, kinked, coiled or holed
- Outside outlet checked: flappers fully open on Air Dry, lint cleared
- Code persists → professional duct cleaning booked; length + elbows noted
- Vent verified clear but d90 remains → contact LG service.
Official LG references
Frequently asked questions
Can I finish the current load with d90 showing?
LG's guidance frames d90 as prompting immediate attention, and its Flow Sense article explains the dryer shuts down to prevent overheating and a fire hazard. The published advice points one way: stop, work the vent checks, and clean the duct — not clear-and-continue.
Is d90 a breakdown?
Usually not an internal dryer malfunction. LG directs users to investigate exhaust restriction first; if the vent is verified clear and d90 persists, contact LG service.
d90 or d95 — does the difference matter?
Only in degree: a Flow Sense estimate of approximately 90% restriction versus approximately 95% — the severe end of the same scale. The checks and the endpoint (professional duct cleaning) are the same; d95 is the reading where nothing should run until the vent is cleared.