Bosch Dishwasher Error Code F18

F18 means the dishwasher's flow meter stationary state monitor has detected unexpected water pulses during a period when the water inlet valve should be fully closed. This points to either an inlet valve that is stuck open or a flow meter generating false signals. The control board triggers this fault to prevent uncontrolled water entry into the tub. Prompt diagnosis is recommended to avoid potential overfill issues.

It is not recommended to continue running the dishwasher while F18 is active. The error indicates that water may be entering the machine outside of its normal cycle, which creates a risk of overfill and potential water damage to your floor and cabinetry. Turn off the water supply to the appliance until the fault is diagnosed and repaired.

Repair costs vary depending on which component is at fault. A replacement water inlet valve typically costs between $25 and $75 for the part, while a flow meter replacement generally falls in the $30 to $80 range. If you hire a technician, labor charges will add to these figures, often bringing the total repair cost to somewhere between $100 and $250 depending on your location and the diagnosis required.

Start by turning off the water supply to the dishwasher and inspecting the water inlet valve for debris, mineral buildup, or signs of wear on the diaphragm. If the valve appears compromised, replacing it is the most common fix. If the valve tests as fully operational, the flow meter should be inspected next for damage or erratic signal output. A qualified technician can use a multimeter to check component resistance and wiring continuity to narrow down the exact fault.

A reset may temporarily clear the F18 code, but if the underlying hardware fault is still present, the error will return during the next cycle. Resetting does not repair a stuck inlet valve or a defective flow meter. A reset is only useful for confirming whether the fault is consistent or was caused by a one-time anomaly such as a brief pressure spike in the water supply.