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Error code reference

Cove Dishwasher Error Code 900122

MCM

Cove codesCove dishwasher codes

MCM: UIM master memory firmware not compatible.

First step from the service manual

Replace the UIM.

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

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What 900122 means on a Cove dishwasher

Error code 900122 on a Cove dishwasher indicates a firmware incompatibility between the MCM (Master Control Module) and the UIM (User Interface Module). Specifically, the MCM has detected that the firmware version stored in the UIM's master memory does not match or is not compatible with what the MCM expects. These two modules communicate during startup to confirm they are running compatible software versions. When that handshake fails due to a version mismatch, the dishwasher will not operate and surfaces this error.

The UIM is the control board assembly that houses the user-facing interface, including buttons and display elements. It contains its own onboard memory that stores firmware. Incompatibility can arise when a UIM has been replaced with a unit carrying a different firmware version, when a firmware update fails partway through and leaves the UIM in a corrupted or partial state, or when the UIM's onboard memory degrades and can no longer correctly report its firmware version to the MCM.

The primary corrective action is replacement of the UIM. Because this is a firmware-level mismatch detected by the MCM, reprogramming or resetting the existing UIM through power cycling will not resolve the underlying incompatibility. A replacement UIM with firmware that is compatible with the installed MCM is required to restore normal operation.

Source: manufacturer service documentation.

Common causes of 900122

  1. 01

    UIM replaced with incompatible firmware version

    Part replacement

    If a UIM was previously swapped in during a repair, it may carry a firmware version that does not match the installed MCM. This is the most common trigger for a 900122 error, especially after prior service work.

  2. 02

    Failed or interrupted firmware update

    Part replacement

    A firmware update that did not complete successfully can leave the UIM's memory in a corrupted or inconsistent state, causing the MCM to flag it as incompatible on the next startup.

  3. 03

    UIM memory corruption or degradation

    Part replacement

    Over time, the onboard flash memory in the UIM can degrade or become corrupted, causing the firmware version data to be unreadable or incorrect when queried by the MCM.

  4. 04

    MCM replaced without matching UIM update

    Part replacement

    If the MCM was recently replaced with a newer version, it may now expect a different UIM firmware version than the one currently installed, creating a version mismatch between the two modules.

See the test procedure for each cause

Frequently asked questions about 900122

What does 900122 mean on a Cove dishwasher?
Error code 900122 means the Master Control Module (MCM) has detected that the firmware in the User Interface Module (UIM) is not compatible with it. The two boards perform a firmware version check at startup, and this code appears when that check fails. The dishwasher will not run until the incompatibility is resolved. Replacing the UIM is the required corrective step.
Can I fix error code 900122 myself, or do I need a technician?
Resolving this error requires replacing the UIM, which involves working with the dishwasher's internal control electronics. A knowledgeable DIYer comfortable with appliance disassembly can potentially complete this repair, but sourcing a UIM with the correct firmware version compatible with your specific MCM is critical. If you are unsure which UIM version to order, a qualified technician can confirm compatibility before purchasing parts.
Will resetting my Cove dishwasher clear error code 900122?
No, a power reset will not clear this error. The code is generated because the MCM actively detects a firmware mismatch with the UIM each time it starts up. Since resetting does not change the firmware on either module, the error will return immediately after power is restored. Replacement of the UIM is necessary to resolve it.
Is it safe to use my Cove dishwasher while error code 900122 is active?
When this error is present, the dishwasher is unable to operate normally because the MCM and UIM cannot communicate in a compatible state. In practice, the unit will not run a wash cycle, so there is no immediate safety hazard. However, the appliance should not be considered functional and the issue should be addressed before attempting to use it.
How much does it cost to fix error code 900122 on a Cove dishwasher?
The cost depends primarily on the price of the replacement UIM, which for Cove dishwashers typically falls in the range of $150 to $400 depending on the specific model and part availability. If you hire a technician for diagnosis and installation, labor costs will add to the total, generally bringing the full repair into the range of $250 to $600 or more.

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