Miele Dishwasher Error Code F51 — Pressure Switch / Turbidity Sensor Fault
What this means
Error F51 on Miele dishwashers indicates the electronic control board has received conflicting data from the pressure switch and/or turbidity sensor. Some Miele models use a turbidity sensor (light sensor in the sump) to measure water clarity, which helps determine wash duration and water temperature. If this sensor disagrees with the pressure switch or gives impossible readings, F51 is triggered.
Alternate codes: F 51
Step-by-step fix
4 stepsClean the turbidity sensor
Remove the lower spray arm and drain filters. The turbidity sensor is a small optical sensor mounted in the sump area. Clean its lens/window with a soft cloth and warm soapy water to remove grease film, limescale, or food residue.
Even a thin grease film on the turbidity sensor can cause incorrect readings that trigger F51.
Check the pressure switch and hose
Inspect the pressure switch hose for blockages, kinks, or disconnection. Blow gently into the hose to confirm it is clear.
A partially blocked pressure switch hose can cause slow or inaccurate water level readings.
Check wiring connections
Inspect the electrical connections to both the turbidity sensor and pressure switch. Reseat all connectors. Look for corrosion or moisture in the connectors.
Moisture from steam can accumulate in sensor connectors over time, causing intermittent faults.
Test or replace the turbidity sensor
If cleaning does not resolve the issue, the turbidity sensor may have failed. On some Miele models it is a replaceable module. Disconnect and measure resistance/voltage at the connector (consult model-specific service data for expected values).
Turbidity sensor specifications vary between Miele model generations — always use the correct replacement part.
When to call a professional
If both the turbidity sensor and pressure switch test normal but F51 persists, the control board's analog input circuit may be faulty. Professional diagnosis is needed.
Related error codes
Information compiled from manufacturer service manuals, official troubleshooting documentation, and appliance repair industry resources. This guide is for informational purposes only — always consult a qualified technician for complex repairs.
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