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LG Dishwasher Error Code HE: What It Means and How to Fix It

LG dishwasher guide · Decoded from manufacturer documentation · Safe homeowner checks only

What is happening inside the machine

An LG dishwasher does not rely on its water heater alone. It takes hot water from your home supply and then boosts it with its own heating element, usually mounted in the sump under the tub, so that the wash reaches the temperature the cycle was designed for. A thermistor, a small temperature sensor fitted to the heater assembly on most models, reports the water temperature back to the control board throughout the cycle. The board compares that reading with the temperature the cycle expects at each stage. When the water fails to warm within the allowed time, or when the reported temperature climbs beyond the programmed safe limit, the board displays HE for Heater Error and stops the cycle. That two sided trigger is why the symptoms matter. Dishes that come out cold, greasy, or with detergent residue point toward the no heat side: the element is not producing heat, or the board is not sending it power. Dishes and water that feel unusually hot, steam that seems excessive, or HE appearing after the machine has been running hot point toward the overheating side: the sensor may be reporting wrongly, or a control relay may be stuck and keeping the heater on. HE is not a drain code and not a fill code. If the tub is full of standing water, start with the LG dishwasher OE guide instead, and if the tub never filled, start with the LG dishwasher IE guide.

Finding the cause

A one time glitch clears after a full power reset

Control boards can latch a false fault after a power flicker or a disturbed cycle. A glitch is the cheapest explanation, so test it first. Switch the dishwasher off, switch off its breaker for at least 5 minutes, then restore power and run a short cycle with no dishes. If HE never returns, the fault was transient and no part is needed. If HE returns at the same stage, usually during heating, the cause is physical and the checks below apply. Do not keep resetting a machine that is overheating: a reset that clears the code without fixing a stuck heater relay only buys one more hot cycle.

Incoming water is too cold for the heater to catch up

The dishwasher heater is a booster, not a replacement for a hot supply. If the water arriving at the machine is cold, the heater may not reach the target temperature in the time the board allows, and HE follows even though every part is healthy. Run the kitchen hot tap closest to the dishwasher for a minute and check the temperature with a thermometer. LG guidance and appliance repair sources commonly put the target at about 120 degrees Fahrenheit. If the tap water is well below that, the water heater setting, a long cold pipe run, or a tempering valve is the real problem. Correct the supply temperature first, then retest with a hot start: run the hot tap until it is hot before starting the dishwasher, so the first fill is already warm.

The thermistor is reporting a wrong temperature

The thermistor translates water temperature into electrical resistance, and the board reads that resistance as a temperature. A thermistor that has drifted, shorted, or gone open circuit tells the board the water is far colder or far hotter than it really is, and HE is the result. With the power off and the machine disconnected, a confident homeowner with a multimeter can measure the thermistor resistance and compare it with the model service values. Repair sources for LG dishwashers commonly cite roughly 11,000 to 14,000 ohms at 77 degrees Fahrenheit for this sensor, but always confirm the value for your exact model before condemning the part. A reading far outside that range, or a reading that jumps around while the sensor is still, points at the thermistor. If you are not comfortable testing with a meter, leave this check to a repair service: guessing at the sensor wastes a part and a visit.

The heating element has failed open or shorted

The element is a resistive heater, and like any heater it can burn out open, so it produces no heat at all, or short in a way that keeps producing heat when it should stop. With the power off, a multimeter resistance check across the element terminals is the decisive test for a confident repairer. Repair sources for LG dishwashers commonly cite roughly 10.8 to 13.2 ohms for a healthy element. An open circuit reading means the element has failed and must be replaced. A reading far below the range, or visible burning, melting, or cracking on the element, means stop and book a repair rather than running the machine again. On many LG models the element and thermistor come as one heater assembly, so replacing the assembly fixes both suspects at once, which is worth knowing before ordering parts separately.

Wiring to the heater is loose, burnt, or corroded

Heat, moisture, and vibration are hard on small connectors. The wiring from the control board to the heater can work loose, corrode at a terminal, or show heat damage where it meets the element. With the power still off and the breaker locked out in your mind, not just switched, look for connectors that are not fully seated, wires that are pinched or bare, and terminals that are discoloured or smell of burning. HE that appears randomly and then vanishes is the classic signature here, because a poor connection remakes and breaks as the machine heats and cools. Do not probe live wiring and do not test for voltage at the heater while the machine is running unless you are trained to do so. If wiring looks burnt or damaged, that is a repair service job, not a reseat and hope job.

The control board relay is stuck or is not sending power

The board is the last suspect, not the first. It earns suspicion only when the supply temperature is correct, the thermistor and element test within range, and the wiring is sound, yet HE persists, or when the water is genuinely overheating with no sensor fault found. A relay stuck closed keeps the heater powered even when the board calls for it to stop, which explains overheating with a healthy sensor. A relay or drive fault that never closes explains no heat with a healthy element. Board diagnosis needs component level testing that no external check can replace, and a board is expensive enough that guessing at it wastes money. If every check above passes and HE persists, stop replacing parts and arrange a professional diagnosis.

Fixing it

1. Reset the control fully, about 10 minutes. Switch the dishwasher off, switch off its breaker for at least 5 minutes, then restore power and run a short cycle with no dishes. Watch whether HE returns at the heating stage.
2. Check the incoming hot water, about 5 minutes. Run the nearest hot tap for a minute and measure the temperature. If it is well below 120 degrees Fahrenheit, correct the supply and retest with a hot start before opening anything.
3. Check the heater wiring with power off, about 15 minutes. With the breaker off, look for loose, corroded, or heat damaged heater connectors. Do not probe live wiring. Reseat only a sound connector.
4. Test the thermistor and element, about 20 minutes, only if you are confident with a meter. With the power off, measure resistance and compare with your model service values. Replace the heater assembly if the element is open or the sensor is far out of range.
5. Retest with a normal load, about 60 minutes. Run a normal cycle and check that dishes come out hot and clean, with no HE return and no unusual steam or heat.

What it costs

Supply temperature first; sensor and element second; board last. Most HE cases end at the free checks or a heater assembly. A control board is the expensive outcome that should never be guessed at.

All prices on this page are estimates based on typical US parts and service pricing. Your model, region and the actual failed part will move the real figure.

Repair or replace note: a heater assembly repair is almost always worth doing, since the fitted cost is a small fraction of a replacement dishwasher. A board repair on an older machine needs a harder look: if the board plus labour passes half the cost of a comparable new dishwasher, or if the pump, racks, and board all need work at once, replacement becomes the sensible choice. Drain behaviour is covered by the OE guide, and fill behaviour by the IE guide. The full list is on the dishwasher hub.

Mistakes that make it worse

• Keeping resetting an overheating machine. Each reset buys one more hot cycle and risks damage to dishes, seals, and the tub. Stop and diagnose instead.
• Replacing the board before testing the element and sensor. A board is the costliest wrong part on this page, and the element and sensor are both cheaper and more likely to fail.
• Ordering a thermistor alone when your model uses a heater assembly. Check the parts diagram first: on many LG models the sensor only comes with the assembly, and a separate sensor may not fit.
• Testing for live voltage at the heater without training. Resistance checks with the power off answer the element and sensor questions safely. Live voltage testing does not add a homeowner decision and adds real shock risk.
• Ignoring a cold water supply. A new heater assembly cannot fix a supply that arrives cold, so the code will return and the new part will look faulty.

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