Miele dishwasher F12 error code
What F12 means on a Miele dishwasher
Water fill or flow fault.
Meaning checked by NAC's engineers, 9 November 2026.
What our engineers say
On a Miele dishwasher, code F12 means there is a fault with the water filling or the flow of water into the machine. You may notice the dishwasher not filling, a water supply warning on the display, or beeping and flashing lights. Sometimes the machine fills briefly and then stops, or keeps filling and draining without starting a wash.
Engineers sometimes find that the part which measures the water flowing into the machine has failed, become stuck or come loose, so the dishwasher cannot tell that water is arriving. Now and then they also find a leaking water inlet valve that has let water collect in the base of the machine.
An engineer will usually check that the water supply and hoses are clear and the pressure is good, then test the flow measuring part to see whether it responds properly. The usual repair is to fit a new flow measuring part, along with a new inlet valve if that is leaking, and then run a full wash to confirm the machine fills, heats and drains correctly. The replacement part often has to be ordered, so it is commonly fitted at a second visit.
Written by our engineers from NAC's own jobs.
Faults this code turns up with
What our engineers found and fixed for each, from NAC's own repair records.
What we fixed. We'll add what our engineers found, the parts they fitted and what customers typically paid once enough of these repairs are confirmed. How we work out our figures.
Before you check anything yourself
- Switch the dishwasher off and unplug it, or turn it off at the isolator switch, before you touch anything. Our guide to safely isolating an appliance walks you through it.
- An error code tells you where to look, not that it's safe to take the dishwasher apart. Don't remove panels or covers to get at the parts it points to: that's an engineer's job.
- If it involves the mains supply, sealed parts, or you're not confident at any point, stop and book a qualified engineer rather than risk injury or further damage.
Rather leave it to us?
- Fixed-price quote before any work starts
- Same or next-day visits where available
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