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Error code reference

Fisher & Paykel Dishwasher Error Code U2

Tub open fault

Fisher & Paykel codesFisher & Paykel dishwasher codes

Tub open fault - the drawer has been sensed as open during a wash cycle, or the exhaust valve has failed open circuit, or the drawer microswitch has failed.

First step from the service manual

Check if the drawer is open; if yes, shut the drawer; if no, check the microswitch is working in diagnostics.

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

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What U2 means on a Fisher & Paykel dishwasher

The U2 error code on a Fisher & Paykel dishwasher indicates a tub open fault. This means the control system has detected that the drawer is open during an active wash cycle, or one of the two components responsible for confirming drawer closure has failed. The two hardware elements involved are the drawer microswitch and the exhaust valve. The microswitch signals the controller when the drawer is fully latched, while the exhaust valve must remain closed during operation. If either component reports an unexpected open state, the machine halts the cycle and throws the U2 fault.

The most straightforward cause is simply that the drawer was physically opened mid-cycle, either accidentally or intentionally. If the drawer is confirmed closed and the error persists, the fault points to a component failure. The exhaust valve failing in an open-circuit condition means the controller cannot confirm valve integrity, which the system interprets as a potential tub breach. Similarly, a microswitch that has failed electrically or mechanically will not send the correct closed signal, triggering the same fault regardless of the drawer's actual position.

Diagnosing this fault begins with a visual check: confirm the drawer is fully closed and properly latched. If the drawer is shut and the error remains active, the next step is to access the dishwasher's diagnostic mode and test the microswitch directly. This will reveal whether the switch is producing the correct signal when the drawer is closed. A switch that reads open in diagnostics with the drawer fully latched confirms switch failure. If the switch tests correctly, attention should shift to the exhaust valve and its wiring for open-circuit conditions.

Source: manufacturer service documentation.

Common causes of U2

  1. 01

    Drawer left open or not fully latched

    Wiring / connection

    The drawer may have been opened during the cycle or was never fully closed before the cycle started. Push the drawer firmly until it clicks into the latch and restart the cycle.

  2. 02

    Faulty drawer microswitch

    Part replacement

    The microswitch that signals the controller when the drawer is fully closed can fail electrically or mechanically, causing the controller to read an open state even when the drawer is shut. This can be confirmed by testing the switch through the diagnostic mode.

  3. 03

    Exhaust valve open-circuit failure

    Part replacement

    If the exhaust valve develops an open-circuit fault, the controller cannot confirm its closed status and interprets this as a tub integrity issue, triggering the U2 code. Inspect the valve and its wiring connections for breaks or corrosion.

  4. 04

    Damaged or misaligned latch mechanism

    Wiring / connection

    Physical damage or debris in the latch assembly can prevent the drawer from seating fully, which means the microswitch never gets depressed correctly. Inspect the latch for obstructions, wear, or misalignment.

  5. 05

    Wiring fault to microswitch or exhaust valve

    Wiring / connection

    Loose, corroded, or broken wiring between the microswitch or exhaust valve and the control board can cause false open-circuit readings without either component itself being defective. Check harness connectors at both ends for secure seating and visible damage.

See the test procedure for each cause

Frequently asked questions about U2

What does U2 mean on a Fisher & Paykel dishwasher?
The U2 code indicates a tub open fault. The dishwasher's control system has detected that the drawer is open during a wash cycle, or it has received an open-circuit signal from the drawer microswitch or the exhaust valve. The machine halts operation until the fault is resolved to prevent running a cycle with an unsecured tub.
How do I fix the U2 error on my Fisher & Paykel dishwasher?
Start by checking that the drawer is fully closed and latched, then restart the cycle. If the error returns with the drawer confirmed shut, enter diagnostic mode to test the microswitch. If the switch fails the diagnostic test, it will need to be replaced. If the switch tests fine, inspect the exhaust valve and associated wiring for open-circuit conditions.
Will resetting my Fisher & Paykel dishwasher clear the U2 error?
A reset may clear the code temporarily, but if the underlying fault is a failed microswitch or exhaust valve, the error will return as soon as the next cycle begins. A reset is only a lasting fix if the cause was simply an open or unlatched drawer during the previous cycle.
Is it safe to use my dishwasher when it shows a U2 error?
The U2 fault causes the dishwasher to halt the cycle, so the machine will not operate normally while the code is active. Do not attempt to bypass the fault, as the code exists to prevent the machine from running with an unsecured drawer or a compromised exhaust valve. Resolve the underlying fault before running another cycle.
How much does it cost to repair a U2 error on a Fisher & Paykel dishwasher?
If the fix is simply closing the drawer, there is no cost. A replacement drawer microswitch typically costs in the range of $20 to $60 for the part, while an exhaust valve replacement may range from $40 to $100 or more depending on the model. Adding a technician's labor for diagnosis and installation can bring the total repair cost to anywhere from $100 to $250 or higher.

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