Miele Dishwasher Error Code F18

F18 on a Miele dishwasher indicates that the flow meter stationary state monitor (B3-4) has detected unexpected pulses from the flow meter while the water inlet valve is not activated. This means water is entering the appliance when it should not be, most commonly because the inlet valve is stuck open or failing to close completely. The dishwasher halts operation to prevent overfilling or potential water damage.

It is not advisable to continue running the dishwasher with an F18 fault active. A stuck-open water inlet valve can cause the appliance to overfill, which may lead to water leakage onto your floor or into surrounding cabinetry. The dishwasher's control system stops operation for this reason, and the underlying issue should be diagnosed and resolved before resuming normal use.

Repair costs vary depending on the cause and whether you hire a technician or perform the repair yourself. A replacement water inlet valve for a Miele dishwasher typically ranges from around $40 to $120 for the part alone. If a technician is needed, total repair costs including labor can range from approximately $150 to $350 or more depending on your location and the extent of the diagnosis required.

Some DIYers with appliance repair experience can address this fault by inspecting the water inlet valve for debris or scale buildup, cleaning the inlet screen, and checking the flow meter for obstructions. If the inlet valve solenoid has failed or the diaphragm is worn, the valve will need to be replaced, which requires disconnecting the water supply and working with electrical components. If you are not comfortable working with water supply lines or internal dishwasher components, a qualified technician is recommended.

Resetting the dishwasher may temporarily clear the F18 code, but the fault will return if the root cause has not been corrected. If the water inlet valve is stuck open or the flow meter is generating false signals, the control board will detect the problem again during the next cycle. A reset should only be used after the underlying issue has been identified and repaired.