LG Dishwasher AE: Water in the Base Pan and How to Stop It

AE means the float switch in the base pan rose high enough to trigger the leak detection circuit. Your LG dishwasher found water where there should be none — below the tub, pooling in the stamped-steel base that sits on your kitchen floor. The machine killed power to everything except the drain pump, which runs continuously trying to evacuate the leaked water.

What Happens When AE Triggers

The base pan float is a simple polystyrene disc on a vertical rod. When water lifts it past the switch contact point, the main board receives an open-circuit signal on that input. The board immediately:

1. Cuts power to the wash motor and fill valve
2. Energizes the drain pump continuously
3. Displays AE and locks out all cycle starts

You might hear the drain pump running even though you did not start a cycle — that is the board trying to clear the base pan. If the leak source is still active, the pump cannot keep up and AE stays.

Finding the Actual Leak Source

AE tells you water reached the base pan. It does not tell you where the water came from. The leak source determines whether this is a $0 fix or a $200 repair.

Pull Out the Dishwasher

Kill the breaker. Close the supply valve under the sink. Disconnect the drain hose from the disposal/tailpiece. Disconnect the supply line. Slide the unit forward on a towel to protect your floor.

Inspect From Below

With the kick plate removed and a flashlight, look for the origin point. Water travels — the drip location is not always the leak location. Look for:

Door gasket corners (most common — 40%): The bottom corners of the door seal collect food debris and hard water deposits. The rubber loses elasticity over 5-7 years, and the compression no longer creates a watertight seal at the corners. Water seeps during the wash phase, runs down the inner door panel, and drips into the base pan through the gap between the tub and the door hinge area.

Test: close the door on a dollar bill at different positions along the bottom seal. If the bill slides out freely at a corner, the gasket is not sealing there.

Sump-to-pump connection (25%): The circular rubber gasket between the sump assembly and the wash pump housing degrades from detergent exposure. A hairline crack in this gasket weeps during the pressurized wash phase. Look for mineral trail marks (white streaks) radiating from the pump junction — that is where evaporated leak water left its mineral signature.

Spray arm seal or bearing (15%): The center wash arm hub where it connects to the sump has a rotating seal. If this seal fails, water sprays downward through the hub during operation. The leak pattern is a wide spray of droplets across the base pan, not a single drip point.

Inlet valve connection (10%): The braided supply line connects to the solenoid valve at the left front. If the valve body cracks (common after hard freezes in unheated garages or during moves) or the connection works loose, pressurized supply water enters the base pan. This leak is unique because it happens even when the dishwasher is not running — supply pressure is always present.

Tub seam or weld crack (10%): Late-life failures on stainless tubs are rare but happen at spot-weld points where dissimilar metals meet. You will see a rust-stained drip point on the outer tub surface. This is not cost-effective to repair — tub replacement exceeds machine value.

The $0 Fix: Float Switch Stuck

Before assuming a real leak exists, check whether the float switch itself is the problem. Reach under the base pan (or remove it) and locate the float assembly — a white or gray plastic disc on a guide post, usually front-center of the base pan.

Manually raise and lower the float. It should glide freely. If stuck in the raised position from a previous small leak that dried and left mineral deposits on the guide, AE triggers falsely. Clean the guide rod and float disc with white vinegar, ensure free travel, dry the base pan completely, and test.

Door Gasket Replacement

The gasket (ADX73550623, $25-45) is a continuous rubber channel that friction-fits around the tub opening perimeter. No adhesive, no screws — it presses into a groove.

1. Start at the bottom center. Grip the old gasket lip and pull outward — it peels from the groove
2. Work around both sides simultaneously toward the top. The top section comes last
3. Clean the groove thoroughly — accumulated deposits prevent the new gasket from seating
4. Starting at the top center, press the new gasket lip firmly into the groove
5. Work down both sides, pressing every 2 inches. Ensure the gasket sits evenly without bunching
6. The bottom corners are critical — press firmly and verify the gasket does not ride up at the corner radius

Pump Junction Seal Replacement

The sump-to-pump gasket (ABQ75742504, $15-30) requires removing the pump from the sump:

1. With the unit pulled forward and on its back, access the pump from below
2. Disconnect the pump's electrical connector
3. Twist the pump assembly counterclockwise (bayonet mount) to release
4. The old gasket sits in the pump inlet — pry it out and clean both mating surfaces
5. Seat the new gasket (dry — no sealant needed), reattach pump with clockwise twist until it clicks

Parts and Cost

Why AE Returns After Repair

The single most common reason AE reappears after a repair: the base pan was not completely dried before reassembly. Even a tablespoon of water left in the pan keeps the float raised. After any AE repair, soak up all residual water with towels, then use a hair dryer on the pan surface. Let the machine sit with the kick plate off for 30 minutes before powering on.

The second most common: fixing the wrong leak. A door gasket was replaced because it looked worn, but the actual leak was the pump junction seal. Both were wet from the same pooled water. Always identify the active drip source, not just the component that looks oldest.

When AE Means Replacement

A tub seam leak on a dishwasher over 8 years old is the one AE cause where replacement makes more sense than repair. Tub replacement ($300-500 for the part alone, plus 2-3 hours labor) exceeds 50% of a new machine's cost. Every other AE cause — gaskets, seals, valves, stuck floats — falls well under the repair-vs-replace threshold.

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