How Do I Fix the F78 Error on My Miele Dishwasher?

Miele is known for producing premium home appliances that combine sleek design with advanced technology. However, even the most reliable machines can sometimes run into issues. If your Miele dishwasher displays an F78 error, it’s a sign that something is interfering with the circulation pump—an essential component responsible for spraying water during the wash cycle.

While this error can be alarming at first, it doesn’t always mean your appliance is beyond repair. In many cases, the F78 error can be resolved through a series of practical troubleshooting steps. This guide will walk you through the most common causes and effective solutions for clearing the F78 code on your Miele dishwasher.

What Does the F78 Error Code Mean?

The F78 error refers specifically to a circulation pump failure. This pump moves water through the spray arms during the wash cycle. When the dishwasher is unable to start or operate the circulation pump properly, it triggers the F78 warning.

This error can result from several underlying causes:

• Electrical fault in the pump

• Blockage in the circulation system

• Faulty control board or wiring

• Software glitch or startup failure

Identifying the root of the problem is key to applying the right fix.

Safety First: Unplug Before You Begin

Before attempting any diagnostic or repair work:

• Turn off the dishwasher at the power source.

• Unplug it from the wall or shut off the circuit breaker.

• Allow it to cool if it has just completed a cycle.

Water and electricity are a dangerous combination, so always prioritize safety.

Step 1: Perform a Power Reset

Sometimes, the F78 error can be caused by a temporary software issue. A power reset is the simplest and fastest solution to try first.

How to perform a reset:

1. Turn off the dishwasher.

2. Unplug it or switch off the circuit breaker.

3. Wait at least 10–15 minutes.

4. Plug the unit back in and power it on.

Run a short cycle and check if the error reappears. If the code is gone, the issue was likely due to a temporary glitch.

Step 2: Inspect for Blockages in Spray Arms and Filters

A common physical cause of the F78 error is a blockage in the circulation system, which puts strain on the pump.

Steps to inspect and clean:

1. Remove the lower basket and take out the spray arms.

2. Check for clogs or food debris in the spray nozzles. Rinse under running water.

3. Open the dishwasher floor and remove the filter unit.

4. Rinse the filter with warm water and scrub off buildup.

5. Examine the impeller area (beneath the filter) to ensure there’s no obstruction.

These blockages can force the pump to work harder, eventually triggering the error.

Step 3: Check the Drain Pump and Circulation Pump

The drain pump and circulation pump are both critical for the water flow process. While F78 points to the circulation pump, a failing drain pump may also cause confusion in the system.

How to inspect:

1. Tilt the dishwasher backward slightly and remove the base plate (if accessible).

2. Locate the circulation pump, typically near the motor.

3. Visually inspect the wiring and connection plugs.

4. Gently rotate the pump impeller with a screwdriver—it should spin freely.

5. Look for signs of damage, burnt areas, or corrosion.

If the pump is jammed or noisy when running, it may need to be replaced.

⚠️ Note: This step may require partial disassembly. If you’re not confident, consult a technician or refer to your Miele service manual.

Step 4: Examine Wiring and Control Board Connections

In some cases, the F78 code can be triggered by loose or damaged wiring between the control board and circulation pump.

Inspection checklist:

• Look for loose connectors at the control module and motor terminals.

• Check wires for fraying, burn marks, or disconnection.

• If you own a multimeter, test for continuity in the wiring harness.

Electrical inconsistencies can confuse the control board, preventing it from activating the circulation pump properly.

Step 5: Run Diagnostic Mode (If Available)

Some Miele dishwasher models allow users to access a diagnostic test mode, which can provide more detailed insight into what’s wrong.

Accessing diagnostics (varies by model):

1. Press and hold the Start button and turn the dishwasher on.

2. Wait for the LED indicators to flash.

3. Release the Start button.

4. Press Start again to begin the test cycle.

Observe which functions complete and where the machine pauses. This can confirm whether the issue is mechanical or electronic.

Refer to your user manual for exact steps to enter diagnostic mode, as they vary between models.

When to Replace the Circulation Pump

If all else fails and your dishwasher still displays the F78 code after cleaning, resetting, and checking components, the circulation pump itself may be faulty.

Replacement cost for a Miele circulation pump can range between $150–$300 USD, not including labor. If your dishwasher is still under warranty, contact Miele customer support for repair or replacement options.

Comparison: Fix vs. Replace

Tips to Prevent F78 Error in the Future

• Rinse dishes before loading to reduce food buildup.

• Clean the filter and spray arms monthly.

• Avoid overloading the racks, which can block water flow.

• Schedule an annual deep clean of internal parts and seals.

• Run a hot water cycle with dishwasher cleaner every few months.