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Error code reference

Cove Dishwasher Error Code 900107

MCM

Cove codesCove dishwasher codes

MCM: 485 firmware not compatible.

First step from the service manual

Replace the MCM assembly.

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

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What 900107 means on a Cove dishwasher

Error code 900107 on a Cove dishwasher indicates a firmware incompatibility detected on the RS-485 communication bus within the Machine Control Module (MCM). The RS-485 protocol is a serial communication standard used internally to allow the MCM to exchange data with other control components in the dishwasher. When the MCM detects that the firmware version running on the RS-485 interface does not match the expected protocol version, it throws this error and halts normal operation to prevent unpredictable behavior or component damage.

The MCM (Machine Control Module) is the central processing board responsible for coordinating wash cycles, sensor inputs, motor control, and communication between subsystems. The RS-485 firmware mismatch typically occurs when a replacement MCM is installed with a firmware version that is out of sync with the rest of the control system, or when a software update process fails and leaves the module in a partially updated state. It can also occur if the MCM itself has experienced an internal corruption of its firmware.

Because the error points specifically to a firmware compatibility failure rather than a wiring or sensor fault, standard reset procedures are unlikely to resolve the issue. The recommended diagnostic action is direct replacement of the MCM assembly. Attempting to continue operating the dishwasher with this error active is not advisable, as the communication failure between the MCM and dependent components means the control system cannot reliably manage cycle functions.

Source: manufacturer service documentation.

Common causes of 900107

  1. 01

    Incompatible replacement MCM installed

    Part replacement

    If a replacement MCM assembly was recently installed, it may carry a firmware version that is not compatible with the RS-485 protocol version expected by the dishwasher system. Verify that the replacement part is the correct version for the specific unit.

  2. 02

    Failed or interrupted firmware update

    Part replacement

    A firmware update that was interrupted by a power loss or error can leave the MCM in a corrupted or partially updated state, causing the RS-485 compatibility check to fail. There is no field-level recovery for this condition; the MCM must be replaced.

  3. 03

    MCM internal firmware corruption

    Part replacement

    Over time or due to a voltage event, the firmware stored on the MCM can become corrupted, causing the RS-485 interface to report a version mismatch. This presents identically to an incompatible module and requires MCM replacement to resolve.

  4. 04

    Faulty MCM from manufacturing or handling

    Part replacement

    In rare cases, a new MCM unit may have a defect that causes it to report an incorrect firmware version on the RS-485 bus. If a recently installed MCM immediately triggers error 900107, a defective module is a likely explanation.

See the test procedure for each cause

Frequently asked questions about 900107

What does 900107 mean on a Cove dishwasher?
Error code 900107 means the Machine Control Module (MCM) has detected a firmware incompatibility on its RS-485 internal communication interface. The RS-485 firmware version does not match what the system expects, so the dishwasher stops operating to prevent control errors. This is an electronics-level fault that requires MCM assembly replacement to resolve.
Can I fix error 900107 myself on a Cove dishwasher?
This error requires replacing the MCM assembly, which involves working with the dishwasher's main control electronics. While a skilled DIYer comfortable with appliance electronics may be able to perform the swap, sourcing the correct MCM version is critical to avoid reintroducing the same incompatibility. Most homeowners should contact a qualified appliance technician for this repair.
Will resetting my Cove dishwasher clear error 900107?
A power cycle or control reset will not clear error 900107. Because the fault is caused by a firmware incompatibility within the MCM hardware itself, the error will return immediately after any reset. The only resolution is replacing the MCM assembly with a compatible unit.
Is it safe to use my Cove dishwasher while error 900107 is active?
The dishwasher should not be used while this error is active. The RS-485 communication failure means the MCM cannot reliably coordinate with other components in the control system, so normal cycle functions cannot be properly managed. Continued use could lead to unpredictable behavior or additional component issues.
How much does it cost to repair error 900107 on a Cove dishwasher?
Repair costs for error 900107 depend on the price of the MCM assembly and labor rates in your area. MCM assemblies for premium dishwashers like Cove typically range from $150 to $400 or more for the part alone, with professional labor adding an additional $100 to $250 depending on the service provider. Contacting a Cove-authorized service technician is recommended for an accurate estimate.

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