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Error code reference

Miele Dishwasher Error Code F51

Heater pressure switch fault

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What the F51 error code actually means

Your Miele dishwasher detected a problem with the electrical circuit that controls the heating element shortly after you started a cycle. The dishwasher checked whether a key switch was receiving power from a relay and got no response, so it stopped and logged this error. This usually means a relay or pressure switch inside the machine has failed and needs to be inspected or replaced.

Diagnostic procedure

The full F51 procedure

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1
First diagnostic step
Check heater relay; replace if contacts are open or solenoid is defective.
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Most common causes of F51

Ranked by how often they cause this code
  1. 1Failed heater relay K1/1 contacts
  2. 2Defective heater relay coil
  3. 3Faulty heater pressure switch
  4. 4Wiring or connection fault

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Questions people ask about F51

What does F51 mean on a Miele dishwasher?
F51 indicates a heater pressure switch fault. One second after a program starts, the control board activates heater relay K1/1 and then checks for a return signal through the heater pressure switch contacts. If that signal is absent, F51 is stored. The fault points to a failure in the relay, the pressure switch, or the wiring between them.
Is it safe to use my Miele dishwasher while F51 is showing?
It is not recommended to continue running the dishwasher with an active F51 fault. The error indicates that the heater circuit is not functioning as expected, which means the machine may not heat water properly and could behave unpredictably. Have the fault diagnosed and repaired before using the appliance again.
How much does it cost to repair a Miele dishwasher F51 error?
Repair costs depend on which component has failed. A heater relay is generally a lower-cost part, while a heater pressure switch or labor for wiring repairs can add to the total. Overall repair costs typically range from around $100 to $350 or more depending on parts needed and local labor rates.
How do I fix the F51 error on my Miele dishwasher?
Start by inspecting heater relay K1/1 for open or damaged contacts and test the relay coil for proper function. If the relay is working correctly, test the heater pressure switch for continuity. Also check all wiring and connectors in the circuit for corrosion or loose terminals. Replace whichever component has failed to resolve the fault.
Will resetting my Miele dishwasher clear the F51 error?
Resetting the dishwasher may temporarily clear the displayed fault code, but F51 will return as soon as another cycle starts if the underlying component failure has not been repaired. The control board will repeat its relay and pressure switch check at program start and store the fault again if the circuit is still open.

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