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Error code reference

Viking Dishwasher Error Code User Interface - Machine Control Communication Error

Communication failure between the user interface and the machine control board.

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Communication failure between the user interface and the machine control board.

First step from the service manual

Check the harness connection between the UI and the machine control; check the Machine Control; check the UI.

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

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What User Interface - Machine Control Communication Error means on a Viking dishwasher

The User Interface to Machine Control Communication Error on a Viking dishwasher indicates a failure in the data signal exchange between two core electronic components: the user interface (UI) board and the machine control board. These two boards communicate continuously during operation, with the UI board transmitting user inputs such as cycle selections and the machine control board relaying operational status back to the display. When this signal is interrupted or cannot be established, the dishwasher flags the error and halts operation to prevent unsafe or unintended behavior.

The most common physical cause of this error is a wiring harness problem between the two boards. Connectors can loosen over time due to vibration, thermal cycling, or improper reassembly after previous service. Damaged wires, corroded pins, or a harness that has been pinched or abraded can all disrupt the communication signal. Before condemning either board, a thorough inspection of the full harness path is essential.

If the harness and connections check out as intact and properly seated, the fault may lie within the machine control board itself or the user interface board. Either board can fail due to power surges, moisture intrusion, or component fatigue. Diagnosis typically involves verifying the harness integrity first, then evaluating each board individually. Replacing the correct board requires isolating the fault through systematic testing rather than assuming one board is at fault over the other.

Source: manufacturer service documentation.

Common causes of User Interface - Machine Control Communication Error

  1. 01

    Loose or disconnected wiring harness

    Wiring / connection

    The ribbon or wire harness connecting the UI board to the machine control board may have come loose at one or both connectors. Reseating the connectors firmly at each end is the first step in diagnosis.

  2. 02

    Damaged or corroded harness wiring

    Part replacement

    Individual wires in the harness may be broken, pinched, or have corroded terminal pins that prevent a clean electrical signal. Inspect the full length of the harness for visible damage and check pin contacts for oxidation.

  3. 03

    Failed machine control board

    Part replacement

    The machine control board may have failed due to a power surge, moisture exposure, or component wear, preventing it from sending or receiving communication signals. If the harness is intact, the control board should be tested and considered for replacement.

  4. 04

    Failed user interface board

    Part replacement

    The UI board itself may be defective and unable to maintain communication with the machine control board. This is typically diagnosed after the harness and machine control board have been ruled out.

  5. 05

    Intermittent power interruption to a board

    Wiring / connection

    If either board is not receiving stable voltage, communication will fail even if both boards are functional. Check that both boards are receiving consistent power as part of the diagnostic process.

See the test procedure for each cause

Frequently asked questions about User Interface - Machine Control Communication Error

What does User Interface - Machine Control Communication Error mean on a Viking dishwasher?
This error means the user interface board and the machine control board have lost the ability to communicate with each other. Both boards need to exchange data continuously for the dishwasher to operate. The fault can stem from a loose harness connection, damaged wiring, or a failure in one of the two boards. The dishwasher will not run normally until communication is restored.
Can I fix this error myself, or do I need a technician?
A knowledgeable DIYer can start by checking whether the wiring harness connecting the two boards is fully seated and undamaged, which requires accessing the interior panels of the dishwasher. If reseating the connectors does not resolve the error, diagnosing and replacing a control board is more involved and typically benefits from professional service. Working with electronic components also carries a risk of further damage if not handled carefully.
Will resetting the dishwasher clear this error?
A power reset by disconnecting the dishwasher from power for a few minutes may temporarily clear the error if it was caused by a transient glitch. However, if there is an underlying wiring or board fault, the error will return once the dishwasher attempts to operate again. A reset alone is not a repair and should be followed by a proper inspection of the harness and boards.
Is it safe to use my Viking dishwasher when this error is displayed?
The dishwasher is designed to halt operation when this communication error is detected, so it typically will not complete a cycle in this condition. It is not advisable to attempt to force the unit through a cycle when a control communication fault is active, as the machine control board may not be able to properly regulate components like the pump, heating element, or water inlet valve.
How much does it cost to repair a Viking dishwasher communication error?
If the fix is as simple as reseating a loose harness connector, there may be little to no parts cost, though a service call fee typically applies. If a machine control board or user interface board needs replacement, parts and labor combined can range from roughly $200 to $600 or more depending on the specific boards required and local labor rates. Getting a diagnosis before authorizing parts replacement helps avoid replacing the wrong component.

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