On an LG dishwasher, "runs but won't clean" is usually a clogged filter, a spray arm that isn't turning, or a fill/heat problem. LG's direct-drive wash motor is strong, so weak cleaning is far more often a clog or a cold wash than a dead motor — and LG shows a clear code (OE, IE, tE) that tells you which.
The known LG issue: LG's wash motor rarely dies, so on an LG a cleaning problem is almost always a clog (filter or inlet screen) or a cold wash (tE) — check those before assuming anything expensive. The on-screen code narrows it in seconds.
What's actually different about a LG
Clogged filter / inlet screen Easy
The bottom filter clogs with food, and the water-inlet screen scales up so the tub underfills — both leave dishes dirty.
What you can check: Twist out and rinse the tub filter; if fill seems weak, close the supply and clean the inlet screen at the valve. Run hot water at the sink first.
Spray arm not spinning (nE) Moderate
A blocked or jammed spray arm — or the vario/spray motor fault (nE) — means water never reaches the upper rack.
What you can check: Clear the spray-arm jets and confirm free spin. A persistent nE code is a technician check.
Not draining fully (OE) Moderate
An OE drain error means the machine holds dirty water and re-washes in it.
What you can check: Clean the filter, check the drain hose and the disposal/air-gap for a clog.
Water not heating (tE) Pro
LG heats the wash inline; a heater or temp-sensor fault (tE) runs the cycle cold so detergent and grease don't clear.
What you can check: A cold tub at cycle-end or a tE code points to the heater circuit — a tech job.
LG dishwasher fault codes
OE
Drain error — clogged filter, hose, or drain pump
IE
Inlet/fill error — supply valve, kink, or clogged inlet screen
nE
Spray (vario) motor fault
tE
Heater / temperature sensor fault (cold wash)
Try this first: Press Power, then hold the button combination your model uses (often Delay/Start held ~3 seconds), or cut power at the breaker for a minute to clear a control glitch.
Get the exact LG part — shipped to your door
With the $50 Quick Check, send a short video and a photo of your LG dishwasher's model number. A real technician confirms the diagnosis and we ship you the exact part with instructions — the $50 is credited toward it. Or we walk you through the fix free.
A dishwasher that runs a full cycle but leaves food, film, or grit behind is rarely broken — most of the time it's starved of one of the three things it needs to clean: a clear filter, freely spinning spray arms, and hot water. Most of these you can fix yourself in a few minutes. Here's the order a tech checks them.
Safety first: These checks are low-risk, but pull the door open mid-cycle carefully — the water inside is very hot.
Clogged filter Easy
Most modern dishwashers have a removable filter in the bottom that traps food. When it packs with gunk, dirty water just recirculates onto your dishes. This is the single most common cause of poor cleaning.
What you can check: Twist out the cylindrical filter in the floor of the tub, rinse it under the tap, and scrub it with a soft brush. Do this monthly and cleaning improves dramatically.
Blocked spray arms Easy
The spray arms have small jets that can clog with hard-water scale, seeds, and debris. If a jet is blocked or an arm can't spin freely, whole sections of the rack never get sprayed.
What you can check: Pop off the spray arms (usually a twist or clip), poke each jet clear with a toothpick, and make sure they spin freely by hand. Also check that tall items aren't blocking them.
Water isn't hot enough Easy
Dishwashers need about 120°F water to dissolve detergent and cut grease. If the incoming water is cold — a common winter problem — detergent won't activate and dishes come out filmy.
What you can check: Run the kitchen sink hot for a few seconds before starting the dishwasher so hot water reaches it right away, and use the "heated" or "sanitize" option.
Hard-water buildup / no rinse aid Easy
Mineral scale coats the tub, jets, and heating element over time, and skipping rinse aid leaves spots and film. Both look like "not cleaning" even when the machine is mechanically fine.
What you can check: Keep the rinse-aid dispenser filled and run a dishwasher cleaner or a cup of vinegar through an empty hot cycle monthly.
Worn wash pump or chopper Moderate
The wash pump pressurizes the spray arms and a chopper grinds food fine enough to rinse away. When either wears out, spray pressure drops and cleaning suffers even with a clean filter.
What you can check: If the filter, arms, and water temp are all good and dishes are still dirty, this is the tech diagnosis — a pump or chopper repair.
Is it worth repairing?
Almost always repair — the top causes are free or a cheap part, and even a wash-pump job is well under the cost of a new dishwasher plus installation. Replacement only makes sense on a very old unit facing a pump failure plus other issues.
Frequently asked questions
Why is my LG dishwasher not cleaning?
On an LG dishwasher, "runs but won't clean" is usually a clogged filter, a spray arm that isn't turning, or a fill/heat problem. LG's direct-drive wash motor is strong, so weak cleaning is far more often a clog or a cold wash than a dead motor — and LG shows a clear code (OE, IE, tE) that tells you which.
Is there a known issue with LG dishwashers not cleaning?
LG's wash motor rarely dies, so on an LG a cleaning problem is almost always a clog (filter or inlet screen) or a cold wash (tE) — check those before assuming anything expensive. The on-screen code narrows it in seconds.
Why is my dishwasher not cleaning the top rack?
The top rack is usually fed by the middle spray arm — if its jets are clogged or it can't spin, or the top rack's water supply tube is blocked, the top comes out dirty while the bottom is fine. Clear the arms and make sure nothing blocks them.
Why are my dishes gritty or filmy after washing?
Gritty means a clogged filter recirculating food; filmy usually means water that's not hot enough, no rinse aid, or hard-water scale. Clean the filter, pre-run hot water at the sink, and keep rinse aid filled.
How much does it cost to fix a dishwasher that won't clean?
Most of the time it's free (filter/arms/water temp) or a low-cost part. A wash-pump repair is around $130 flat labor plus the part, and your $50 Quick Check credits toward it.