Whirlpool Washer Error Code F42

F42 indicates that the User Interface board sent a cycle selection to the Central Control Unit (CCU) that the CCU does not recognize as supported. This is caused by a software or firmware mismatch between the two control boards, or by corrupted memory on the CCU. The washer halts operation when this conflict is detected and displays F42 to alert the user that the control system needs attention.

A standard power reset is unlikely to permanently clear F42, because the underlying cause is a software mismatch or corrupted memory rather than a temporary glitch. The washer will most likely display F42 again as soon as a cycle is selected. The correct first step is to perform the Service Cycle pairing procedure, not just a power cycle.

Repair costs vary depending on which component needs replacement. A User Interface board typically costs between $75 and $200 for the part, while a CCU can range from $150 to $350 or more. Adding professional labor, total repair costs generally fall between $150 and $500 depending on the parts required and your location. If both boards need replacement, costs will be toward the higher end of that range.

A technician or experienced DIYer can attempt to resolve F42 by performing the washer's Service Cycle, which attempts to pair and synchronize the UI and CCU software. If that does not work, the repair requires physically replacing the User Interface board and potentially the CCU, which involves working with electrical components. If you are comfortable with appliance board replacement and have access to the correct parts, it is a feasible DIY repair, but if the fault persists after a pairing attempt, professional diagnosis is recommended.

The washer will not operate normally when F42 is active, as the error prevents unsupported cycle commands from being executed. This is a protective behavior, not a safety hazard in itself, but you should not attempt to bypass the error or force the machine to run. Continuing to use the washer without resolving the underlying control board issue could lead to additional faults.