LG Dishwasher AL Error Code — What It Means & How to Fix It

What Does This Error Mean?

The AL error on an LG dishwasher indicates a water level abnormality — water is not at the expected level when it should be. This can mean the dishwasher cannot fill with enough water to wash, or it detected water when it should be empty. Common causes include a blocked filter, a water inlet issue, a drain problem, or a faulty water level sensor. You may notice the dishwasher not washing properly, stopping mid-cycle, or making unusual sounds during the fill phase.

Affected Models

LG LDT5665V
LG LDFN4542S
LG LDP6797ST
LG LDT7808BD
Most LG built-in dishwashers

Common Causes

Clogged dishwasher filter preventing proper water circulation and level sensing
Kinked or blocked water supply hose restricting water flow into the tub
Faulty water inlet valve not opening fully to allow sufficient water entry
Water level sensor (pressure switch) is faulty and reading incorrect levels
Blocked or improperly installed drain hose allowing water to remain in the tub

How to Fix It

Remove and clean the dishwasher filter assembly at the bottom of the tub. Rinse it under running water and scrub with a soft brush. A clogged filter is the most common cause of water level issues.

LG recommends cleaning the filter monthly. Twist counterclockwise to remove the cylindrical filter, then lift out the flat filter beneath it.
Check the water supply hose for kinks or blockages. The hose runs from the hot water valve under the sink to the back of the dishwasher. It should be straight with no sharp bends.

The hot water valve under the sink must also be fully open — turn counterclockwise as far as it goes.
Run a short cycle and listen during the fill phase. You should hear water entering the tub within the first minute or two. No fill sound may indicate a stuck water inlet valve.

A water inlet valve that is partially blocked by mineral deposits is a common failure in hard-water areas.
Check that the drain hose is installed at the correct height. The drain hose must have a high loop under the sink counter or be connected to an air gap. A hose that runs too low can siphon water back, confusing the level sensor.

The high loop prevents back-flow and is a required installation step listed in LG's installation guide.
If all of the above check out, have an appliance technician test the water level pressure switch. A faulty switch will give incorrect readings regardless of actual water level.

Water level pressure switches on LG dishwashers are typically $15 to $40 for the part.

When to Call a Professional

If the filter is clean and the hoses are fine but AL persists, the water level sensor or inlet valve needs professional testing. An appliance technician can test the water inlet valve solenoid and the pressure switch with a multimeter. Do not ignore persistent water level errors — they can lead to poor cleaning results or potential overfill situations.

Frequently Asked Questions

Is AL the same as OE or IE on LG dishwashers?

They are related but not the same. IE means water is not entering the dishwasher at all. OE means water is not draining. AL indicates the water level detected by the sensor does not match what is expected — which can be caused by either a fill issue or a drain issue, as well as a faulty sensor.

How often should I clean my LG dishwasher filter?

LG recommends cleaning the filter at least once a month. If you run the dishwasher daily or wash heavily soiled dishes, clean it every two weeks. A clean filter is the single most important maintenance step for preventing water level and drainage errors.

Will the AL error clear itself?

Not until the underlying issue is resolved. Clearing the error by cycling power without fixing the root cause will result in the error returning as soon as the next cycle starts. Fix the filter, hoses, or sensor issue first.