Miele Dishwasher F78 — What It Means & How to Fix It
F78 points at the circulation (wash) pump — a blocked impeller, a connection gone bad, or the frequency converter that drives it — and mostly ends at the technician.
What this code means
F78 is the circulation pump's fault code. The dishwasher can't build proper wash pressure, and the repair references split the causes into three: something blocking the pump's impeller, a lost connection between the electronics and the pump, or a failed frequency converter (the electronics that run the pump motor). A quick look through the filter opening for an obvious blockage is the only owner-safe step; the pump and converter live under the machine and need real diagnosis.
Documented for G-series dishwashers by The Appliance Guys and Domex, with the same description (blocked pump, interrupted connection, frequency converter fault); modern G 7xxx machines share the code family.
Most likely causes
| Cause | How likely | DIY-fixable? |
|---|---|---|
| Object blocking the wash pump impeller | Occasional | Limited — check via the filter opening |
| Interrupted connection between electronics and pump | Less common | No — technician job |
| Frequency converter or pump motor failed | Less common | No — technician job |
What you can try yourself
- Unplug the dishwasher before doing anything near the sump.
- Remove the filter combination and look into the pump area for debris you can safely lift out by hand.
- If the impeller feels jammed and you can't free it through the opening, stop — the pump is below the tub.
- Check the pump's electrical connector only if you can reach it without disassembly, looking for burnt or loose contacts.
- For anything beyond that, book a technician — pump and converter replacement is bench work.
When to call a technician
- F78 returns after the filter opening is clear.
- A burnt or hot smell from the machine's base.
- The dishwasher makes a grinding noise and throws F78.
Typical professional repair cost: About $250–500 for circulation pump or frequency converter work with a technician.
Frequently asked questions
Is F78 the same as not draining?
No — F78 is about the pump that pushes water around inside the tub, not the pump that empties it. Draining problems are F11 territory.
I found a piece of glass in the pump — will F78 clear now?
If a blockage was the cause, clearing it can restore the pump — run a short cycle and see. If F78 still shows, the motor side is the problem.
Sources checked
Error meanings can vary by model. This guide was checked against the documentation above; use the manual for the model number on your own appliance when it differs.
Related Miele codes
- Miele Dishwasher F01 F01 is the dishwasher telling you its water-temperature sensor is short-circuited — the machine will stop heating so nothing comes out properly cleaned until it's sorted.
- Miele Dishwasher F02 F02 is F01's twin on the same sensor: the water-temperature sensor circuit reads open, so the heater stands down and a cycle can finish cold and unwashed.
- Miele Dishwasher F11 F11 means the wash cabinet isn't draining — usually a mis-seated non-return valve, a blocked drain pump or clogged filters, and Miele USA walks owners through fixing it.
- Miele Dishwasher F12 F12 means the dishwasher isn't taking in enough water, and Miele's own support page gives the three owner checks: faucet on, clean the inlet filter, straighten the hose.
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