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Error code reference

KitchenAid Washer Error Code F21

Pressure switch failure

KitchenAid codesKitchenAid washer codes

Pressure switch failure - control does not detect water entering or pressure switch does not trip after 10.5 gallons detected by flow sensor.

First step from the service manual

Unplug washer or disconnect power; check to verify that the pressure switch is operational.

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

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What F21 means on a KitchenAid washer

The F21 error code on a KitchenAid washer indicates a pressure switch failure. Specifically, the control board has determined either that water is not entering the tub as expected, or that the pressure switch has failed to trip after the flow sensor detects 10.5 gallons of water intake. The pressure switch is responsible for monitoring the water level inside the drum and communicating that information to the control board. When the control board cannot confirm proper water entry or pressure switch activation within the expected window, it halts the cycle and displays F21.

The pressure switch operates by responding to air pressure changes in a small hose connected to the bottom of the wash tub. As water fills the tub, air pressure increases in this hose and actuates the switch at a preset threshold. If the hose is kinked, cracked, clogged, or disconnected, the switch will never receive the correct pressure signal and will fail to trip. Likewise, if the switch itself has failed internally, it will not send the proper signal to the control board even when water levels are correct.

Diagnosing F21 begins with disconnecting power to the washer before inspecting the pressure switch and its associated wiring harness. The technician should check for continuity through the switch, verify the pressure hose is intact and unobstructed, and confirm that the wiring connections between the switch and control board are secure. A faulty inlet valve that restricts water flow can also contribute to this fault by preventing sufficient water from entering the tub, which means the flow sensor never reaches the 10.5-gallon threshold that would trigger switch evaluation.

Source: manufacturer service documentation.

Common causes of F21

  1. 01

    Faulty pressure switch

    Part replacement

    The pressure switch itself may have failed and is not tripping or sending the correct signal to the control board even when water is present. This can be confirmed by testing the switch for proper continuity and response to air pressure.

  2. 02

    Kinked or damaged pressure hose

    Wiring / connection

    The small hose connecting the tub to the pressure switch may be kinked, cracked, or clogged with residue, preventing accurate pressure readings. Visually inspect the hose along its full length and blow through it to check for blockages.

  3. 03

    Restricted or failed water inlet valve

    Part replacement

    If the inlet valve is not opening fully or is partially blocked by sediment, the washer may not reach the 10.5-gallon flow threshold required to evaluate the pressure switch. Inspect the inlet valve screens and test the valve solenoids for proper operation.

  4. 04

    Loose or corroded wiring connections

    Wiring / connection

    Poor electrical connections between the pressure switch and the control board can interrupt the signal path and trigger F21. Check all connectors at the pressure switch and at the control board for corrosion, looseness, or damage.

  5. 05

    Failed control board

    Part replacement

    In less common cases, the control board itself may be unable to correctly read or process the signal from the pressure switch even when that component is functioning properly. This is typically diagnosed after all other components have been ruled out.

See the test procedure for each cause

Frequently asked questions about F21

What does F21 mean on a KitchenAid washer?
F21 indicates a pressure switch failure on a KitchenAid washer. The control board did not detect water entering the tub, or the pressure switch did not trip after the flow sensor registered 10.5 gallons of water intake. The washer stops the cycle until the issue is resolved. The fault points to the pressure switch, its connected hose, the inlet valve, or the wiring in that circuit.
Can I fix F21 on my KitchenAid washer myself?
Some causes of F21 are DIY-friendly, such as inspecting and clearing a kinked pressure hose or tightening loose wiring connections. Always unplug the washer before performing any inspection or repair. Replacing the pressure switch or inlet valve requires basic mechanical skills and is manageable for experienced DIYers. If the control board is the root cause, professional repair is typically recommended.
Is it safe to keep using my washer when it shows F21?
No, you should not continue running the washer while F21 is active. The error means the machine cannot confirm proper water levels, which could result in the washer running dry or not completing cycles correctly. Continued use without resolving the fault risks further damage to the motor or other components. Disconnect power and diagnose the issue before resuming use.
How much does it cost to repair a KitchenAid washer with error code F21?
Repair costs depend on the root cause. Replacing a pressure switch typically ranges from $30 to $80 for the part, plus labor if a technician is hired. An inlet valve replacement generally runs $40 to $100 for parts. Control board replacement is the most expensive scenario and can range from $150 to $350 or more for parts alone. A professional service call adds labor costs on top of any parts.
Will resetting my KitchenAid washer clear the F21 error code?
Unplugging the washer and restoring power may temporarily clear the F21 code, but the error will return if the underlying issue is not fixed. A reset does not repair a faulty pressure switch, blocked hose, or failing inlet valve. Clearing the code without addressing the root cause means the washer will likely fault again during the next fill cycle. A proper repair is needed for the code to stay clear.

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