Dishwasher
F12
The F12 error code on a Whirlpool dishwasher signals a water supply problem — specifically, the machine isn’t detecting enough water entering during the fill cycle. It’s a common fault and often fixable without a callout, but ignoring it will leave your dishes dirty and could stress the pump.
What does this error mean?
F12 tells you the dishwasher’s control board expected water to reach a certain level within a set time, but it didn’t get there. The machine is essentially saying: ‘I tried to fill, but something blocked or restricted the water coming in.’ This triggers a safety cut-off to prevent the pump running dry and burning out.
Est. repair cost
£0 (DIY reset/filter clean) | £15–£30 (DIY door latch) | £80–£140 (professional inlet valve or sensor repair)
🔍 Likely causes
🛠️ Step-by-step fix
Reset the machine first: turn it off at the mains, wait 60 seconds, then switch back on and start a new cycle. A temporary glitch can trigger F12 and a reset often clears it.
Check the water supply: make sure the tap/stopcock behind or under the unit is fully open. It sounds obvious but it’s the most common overlooked cause.
Inspect the inlet hose: pull the dishwasher forward slightly and check the hose running from the wall to the machine. Straighten any kinks and ensure it isn’t crushed against the wall or cabinet.
Clean the inlet filter screen: turn off the water supply, unscrew the inlet hose from the back of the dishwasher, and remove the small mesh filter inside the connection port. Rinse it under the tap to remove limescale and debris, then refit and test.
Check the door latch: open and firmly close the dishwasher door, listening for a solid click. Inspect the latch mechanism for visible damage or debris. If the door feels loose or the latch is broken, a replacement door latch (around £15–£30) is a straightforward DIY part swap.
Test household water pressure: if the above steps don’t help, run a cold tap in your kitchen at the same time you try to start the machine. Weak flow points to a pressure issue — contact your water supplier or a plumber.
📞 When to call a professional
If cleaning the inlet filter and checking the hose doesn’t resolve F12, the most likely culprit is the inlet solenoid valve or the pressure sensor — both require the machine to be partially disassembled and involve the electrical supply. Call a Whirlpool-approved or Which?-trusted appliance engineer at that point. Tell them: ‘My Whirlpool dishwasher is showing F12, I’ve checked the hose, inlet filter, and water supply, so I suspect the inlet valve or pressure sensor.’
⚖️ Repair or replace?
A professional repair for a faulty inlet valve or pressure sensor typically costs £80–£140 in the UK including parts and labour. If your dishwasher is under 5 years old, repair is almost always worth it. Over 8 years old with multiple previous faults, a replacement mid-range dishwasher (£300–£500) is better value — modern machines are also significantly more energy and water efficient.