Miele Dishwasher Error Code F79

F79 indicates a communication fault between the circulation pump frequency converter electronic and the main SLT control board. The dishwasher requires this communication link to regulate pump speed and confirm proper operation during wash cycles. When the link fails or produces invalid signals, the machine stops and displays F79. The fault can involve the wiring harness, supply voltage, the frequency converter, or the circulation pump itself.

Resetting the dishwasher may temporarily clear the error code, but F79 will return if the underlying fault in the wiring, voltage supply, frequency converter, or circulation pump has not been corrected. A reset is useful for confirming whether the fault is intermittent, but it is not a repair. Persistent F79 codes require proper component-level diagnosis.

Repair costs vary depending on which component is at fault. A wiring harness repair or connector fix is generally less expensive, while replacing the frequency converter electronic or the SLT control board will cost more, often ranging from a few hundred dollars up to several hundred dollars including parts and labor. Getting a diagnostic assessment from a Miele-experienced technician will give you a more precise estimate based on your specific machine.

Some basic checks, such as inspecting visible wiring connectors for loose or corroded connections, are within reach for a confident DIYer. However, properly diagnosing this fault requires a multimeter to check supply voltage at the SLT terminals and the ability to evaluate electronic components. Most homeowners will benefit from having a qualified appliance technician perform the diagnosis and any component replacement.

The dishwasher will typically not complete a wash cycle when F79 is active, as the machine halts operation upon detecting the fault. Attempting to force operation with a known communication fault between the control board and the pump could potentially cause further damage to electronic components. It is best to leave the machine off until the fault is diagnosed and repaired.