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Error code reference

GE Dishwasher Error Code F18

Non-draining sump (turbidity based).

GE codesGE dishwasher codes

Non-draining sump (turbidity based).

First step from the service manual

Check drain pump operation, turbidity sensor harness, replace sensor.

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

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  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
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What F18 means on a GE dishwasher

The F18 error code on a GE dishwasher indicates a non-draining sump condition detected through the turbidity sensor system. Rather than relying solely on a float switch or timer-based drain cycle, GE dishwashers equipped with turbidity-based monitoring use an optical or infrared sensor to measure water clarity and fluid presence in the sump. When the sensor detects standing water in the sump after the drain cycle should have completed, the control board logs F18 and halts operation to prevent potential overflow or pump damage.

The drain pump is the first mechanical suspect in an F18 fault. A failed pump motor, a pump impeller jammed with debris, or a clogged drain hose can all prevent adequate water evacuation from the sump. The turbidity sensor harness is also a frequent culprit: corroded connector pins, a chafed wire, or a loose connection can cause the control board to misread sump conditions even when the drain pump is functioning correctly. The sensor itself can fail due to mineral scale buildup on its optical window or internal component degradation.

Diagnosis should begin by confirming whether the drain pump is actually running during the drain cycle and moving water out of the machine. Inspect the drain hose for kinks, blockages, or an improperly routed high loop. If the pump operates normally and the sump clears, focus attention on the turbidity sensor harness for continuity and the sensor itself for contamination or failure. A sensor that cannot be cleaned of scale deposits will need replacement to resolve the fault reliably.

Source: manufacturer service documentation.

Common causes of F18

  1. 01

    Clogged or obstructed drain pump

    Wiring / connection

    Food debris, broken glass, or a foreign object lodged in the pump impeller can prevent the pump from moving water out of the sump. Remove the lower spray arm and filter assembly to inspect and clear the pump inlet.

  2. 02

    Blocked or kinked drain hose

    Wiring / connection

    A drain hose that is kinked behind the dishwasher, clogged with grease buildup, or lacking a proper high-loop installation will restrict water flow out of the sump. Inspect the full length of the hose from the pump outlet to the sink drain or garbage disposal connection.

  3. 03

    Turbidity sensor harness fault

    Wiring / connection

    Corroded connector pins, a broken wire, or a loose harness connection on the turbidity sensor circuit can cause the control board to register standing water even when the sump has drained properly. Check the harness for continuity and inspect connector terminals for corrosion.

  4. 04

    Failed or contaminated turbidity sensor

    Part replacement

    Mineral scale or film buildup on the sensor's optical window can prevent accurate water clarity readings, triggering a false F18 fault. If cleaning the sensor surface does not resolve the error, the sensor itself has likely failed and requires replacement.

  5. 05

    Failed drain pump motor

    Part replacement

    If the pump impeller is clear but the pump does not run or hums without moving water, the pump motor windings may have failed. A non-functional drain pump will consistently leave water in the sump and trigger F18 on every drain cycle.

See the test procedure for each cause

Frequently asked questions about F18

What does F18 mean on a GE dishwasher?
F18 indicates that the dishwasher's turbidity sensor detected water remaining in the sump after the drain cycle completed. The control board uses this sensor to monitor whether the tub has properly evacuated water. The fault can stem from a blocked drain pump, a clogged drain hose, a faulty sensor harness, or a failed turbidity sensor. The dishwasher stops operation when this code appears to prevent overflow or pump damage.
Can I fix the F18 error myself without calling a technician?
Many F18 faults are caused by drain clogs that a homeowner can address without special tools. Start by cleaning the filter assembly at the bottom of the tub, checking the drain hose for kinks, and clearing any debris from the pump inlet area. If the drain path is clear and the error persists, the turbidity sensor or its wiring harness may need professional inspection or replacement.
Is it safe to keep using my dishwasher when F18 is showing?
It is not recommended to run the dishwasher while F18 is active. The code indicates the machine detected standing water in the sump, which means the drain cycle did not complete as expected. Continuing to run cycles could lead to water overflow onto the floor or prolonged pump operation under stress. Diagnose and resolve the underlying cause before resuming normal use.
How much does it cost to repair an F18 error on a GE dishwasher?
Repair costs vary significantly depending on the cause. Clearing a clogged drain hose or pump impeller yourself costs nothing beyond your time. Replacing a turbidity sensor typically runs between $20 and $60 for the part alone. If a drain pump motor has failed, parts and professional labor combined can range from $150 to $350 depending on the model and your location.
Will resetting the dishwasher clear the F18 error code?
A reset may temporarily clear the F18 code from the display, but the error will return on the next cycle if the underlying problem has not been fixed. Resetting the control board does not repair a clogged drain, a failed pump, or a faulty turbidity sensor. Address the root cause first, then perform a reset to confirm the fault no longer triggers during normal operation.

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