Miele Dishwasher Error Code F68

Error code F68 on a Miele dishwasher indicates a fault in the circulation pump control circuit. Specifically, the frequency converter is detecting a speed signal from the electronic control board at a time when no speed command should be present. In other words, the control board is sending a target speed signal to the frequency converter even during a shutoff state, causing the circulation pump to continue operating when it should be idle. This points to a communication or logic failure originating within the electronic control unit rather than a purely mechanical pump fault.

The frequency converter in Miele dishwashers is responsible for regulating the speed of the circulation pump motor by converting incoming power into a variable frequency output. When the control board erroneously transmits a speed signal during a shutoff phase, the frequency converter interprets this as a valid run command and keeps the pump spinning. This abnormal behavior can manifest as the wash pump continuing to run after a cycle ends or during phases when the pump should be off.

Because the fault is traced to the electronic control board generating an incorrect signal, the primary diagnostic step is replacement of the electronic control unit. The control board governs all timed outputs and speed commands to the frequency converter, and an internal failure within its logic circuitry or firmware can produce persistent erroneous signals. Other components such as wiring harnesses and connectors between the board and frequency converter should be inspected for damage or poor contact before committing to a board replacement, but the control board itself is the most likely root cause.