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Error code reference

Kenmore Dishwasher Error Code 6-4

Float switch open

Kenmore codesKenmore dishwasher codes

Float switch open — overfill switch stuck in open position and/or dishwasher not level; drain hose check valve not sealing; fill valve triac on control shorted; fill valve mechanically stuck open; too many suds; or open fuse to fill valve.

First step from the service manual

Remove any items stuck under float. Verify float moves freely and you hear the click of the switch contacts. Check levelness. Measure switch resistance.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What 6-4 means on a Kenmore dishwasher

Error code 6-4 on a Kenmore dishwasher indicates the control board has detected the overfill float switch in a continuously open position during a fill cycle. The board monitors the float switch to confirm water has not risen above a safe level. When the switch reads open at a time when it should be closed, the board interprets this as either an actual overfill condition or a fault in the float switch circuit itself. Possible causes include a mechanically stuck-open fill valve, a shorted fill valve triac on the control board, a failed drain hose check valve allowing water to backfill, excessive suds displacing the float, or an open fuse in the fill valve circuit.

For homeowners, the float is a small plastic dome or cylinder on the bottom of the dishwasher tub floor. It rises with water level and triggers a switch underneath the tub when water gets too high, cutting off the fill. If this float is stuck up, jammed by debris, or the switch beneath it has failed, the dishwasher sees an overfill signal and stops operating normally. The machine may also not be level, causing water to pool toward the float side and triggering a false reading. Checking that the float moves freely and that the dishwasher sits level are the first physical checks to make before replacing any parts.

Source: manufacturer service documentation.

Common causes of 6-4

  1. 01

    Float stuck or obstructed

    Wiring / connection

    A food particle, utensil, or debris wedged under the float cap can hold it in the raised position, keeping the switch open even when water levels are normal. Physically lifting and releasing the float should produce an audible click from the switch contacts below.

  2. 02

    Float switch failed open

    Part replacement

    The float switch itself can fail electrically, reading open circuit regardless of float position. Measuring resistance across the switch terminals with a multimeter should show near-zero ohms when the float is down; an open reading with the float down confirms a failed switch.

  3. 03

    Fill valve mechanically stuck open or shorted triac on control board

    Part replacement

    A fill valve that will not close allows water to continuously enter the tub, eventually raising the float and triggering the overfill switch. A shorted fill valve triac on the control board can produce the same symptom by sending unintended power to the fill valve even when the board commands it off.

  4. 04

    Drain hose check valve not sealing

    Part replacement

    If the check valve in the drain hose fails to seal, water from the drain line can siphon back into the tub between cycles, raising the water level enough to lift the float and produce a 6-4 code. Inspecting and replacing the check valve resolves backflow-related overfill conditions.

See the test procedure for each cause

Frequently asked questions about 6-4

What does error code 6-4 mean on a Kenmore dishwasher?
Code 6-4 means the control board detected the overfill float switch in the open position, indicating the dishwasher may have too much water in the tub or there is a fault in the float switch circuit. The board uses this signal to prevent flooding. The root cause could be a stuck float, a failed switch, a fill valve that will not close, a leaking drain check valve, or excessive suds lifting the float prematurely.
How do I fix error code 6-4 on my Kenmore dishwasher?
Start by removing the bottom rack and locating the float, which is a small dome on the tub floor. Clear any debris from around it, lift it manually, and confirm you hear a click when it drops back down. Next, verify the dishwasher is level using a bubble level on the tub floor. If the float moves freely and the unit is level, use a multimeter to measure resistance across the float switch terminals under the tub. A reading of open circuit with the float in the down position means the switch needs replacement. If the switch tests good, inspect the fill valve and drain check valve for failure.
Is it safe to use my Kenmore dishwasher when it shows a 6-4 error?
Running the dishwasher with an active 6-4 code carries a risk of overflow if the underlying cause is a fill valve stuck open or a failed float switch. The safety circuit that is supposed to stop filling is not functioning reliably. Avoid running full cycles until the float, switch, and fill valve have been inspected and confirmed working correctly.
Can too many suds cause a 6-4 code on a Kenmore dishwasher?
Yes. Excessive suds can physically raise the float even when the actual water level is within the normal range, triggering the overfill switch and producing a 6-4 code. This typically happens after using hand dish soap or too much detergent. Run a rinse cycle with no detergent, or place a small amount of cooking oil in the tub to break down the suds, then check whether the code clears.
How much does it cost to repair a Kenmore dishwasher with a 6-4 error code?
If the fix is simply clearing debris from the float or adjusting leveling legs, the repair costs nothing beyond your time. A replacement float switch typically costs between $15 and $40 for the part, and most homeowners with basic tools can replace it in under an hour. A failed fill valve runs $20 to $60 for the part. A shorted fill valve triac requiring control board replacement is the most expensive scenario, with boards ranging from $100 to $250 or more depending on the model. If both the board and valve have failed, professional diagnosis is advisable before ordering parts.

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