Dishwasher
E4
The E4 error code on a Siemens dishwasher indicates a water overflow or overfilling fault — meaning the machine has detected more water in the tub than it should. It’s a moderately serious fault that stops the wash cycle to prevent a flood, but in many cases it’s something you can resolve yourself.
What does this error mean?
The E4 code is triggered when the dishwasher’s pressure sensor or float switch detects that water has risen above the safe maximum level inside the appliance. Siemens dishwashers are programmed to halt immediately when this happens to protect your kitchen floor and cabinets. It can also activate the AquaStop safety system, which shuts off the water inlet to prevent further flooding.
Est. repair cost
£80–£150 professional repair; £20–£60 DIY if replacing inlet valve or float switch yourself
🔍 Likely causes
🛠️ Step-by-step fix
Cancel the programme and switch the dishwasher off at the mains. Leave it for 10–15 minutes, then restart — if it was a temporary sensor glitch, this may clear the error.
Check the base of the machine: pull the dishwasher forward slightly and look underneath for pooled water in the drip tray. If you find water, mop it out with a towel and check for any visible leaks from hoses or the door seal.
Clean the filter assembly at the bottom of the dishwasher tub — remove, rinse under a tap, and replace it. A blocked filter is one of the most common causes of drainage-related overflow faults.
Inspect the drain hose at the back of the machine. It should loop up high (ideally secured to the underside of the worktop) before dropping to the standpipe. A hose sitting too low can siphon water back into the tub. Reposition if needed.
Check you’re using the correct dishwasher tablet or powder — never use standard washing-up liquid. If foam is visible inside the machine, run a short empty cycle with no detergent to flush it out.
If the error persists after all the above, the inlet valve, float switch, or pressure sensor is likely faulty. These parts require the appliance to be partially dismantled — stop here and call a qualified appliance engineer.
📞 When to call a professional
If the E4 code returns after cleaning the filter, clearing the drain hose, and mopping out the drip tray, the fault is most likely a failed water inlet valve, float switch, or pressure sensor — all of which require disassembly to access safely. Call a Siemens-approved or independent appliance engineer and tell them: ‘My Siemens dishwasher is showing an E4 overflow error, I’ve cleared the filter and drain hose, and I found water in the base tray.’ This gives them the full picture before they arrive.
⚖️ Repair or replace?
A professional repair for an E4 fault — typically replacing the inlet valve (£30–£60 for the part) or float switch — will usually cost £80–£150 all-in from a UK appliance engineer. If your Siemens dishwasher is under 7 years old, repair is almost always the right call. If it’s 10 years or older and this isn’t the first fault, a replacement dishwasher (£350–£700 for a comparable Siemens model) is worth serious consideration rather than investing in repairs.