GE Dishwasher Error Code F18

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.

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.

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.

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.

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.