Miele Dishwasher Error Code F3

The F3 error code on a Miele dishwasher indicates an electronics fault related to the program selector switch. Specifically, the control board was unable to recognize the position of the program selector switch during operation or at startup. The selector switch communicates its current position to the main control electronics via a series of electrical signals, and when those signals fall outside the expected parameters or are absent entirely, the control board logs F3 and halts operation to prevent running an unintended or undefined cycle.

The fault can originate at several points in the signal path between the selector switch and the control board. The switch itself may have worn contacts, a broken internal track, or corrosion that prevents a clean electrical signal from being generated. Equally, the wiring harness connecting the switch to the control board may have a damaged wire, a loose connector, or an intermittent open circuit. In some cases the control board itself is the source of the fault, with a failed input circuit unable to correctly read even a fully functional switch.

Because this is classified as an electronics fault rather than a mechanical or sensor fault, diagnosis typically involves checking continuity and resistance through the selector switch contacts at each program position, inspecting the harness for physical damage or loose terminals, and comparing readings against expected values. If the switch and wiring check out, the control board becomes the primary suspect and will likely require replacement.