The short answer
E3400 is a water-intake fault: the table records an issue with water flowing into the dishwasher or the filling system, with the water possibly unable to enter at all. Most of the causes are on the supply side, outside the machine, and every one of those is free to check.
Code table
Reference| code | meaning | owner-checkable |
|---|---|---|
| E3400 | There is an issue with water flowing into the dishwasher or the filling system. The water may not be able to enter the dishwasher. | partly |
| E3300 | There is an issue with water flowing into the dishwasher or the filling system. The water may not be able to enter the dishwasher. | see page |
| E6001 | There is a heat pump internal heater fault/error. | see page |
What you observe
- The cycle stalls early with little water in the tub — The fill step is where the control gives up.
- Filling is audibly slow or does not start — No inrush at all points at the tap or the hose.
- The wash arms turn weakly or not at all — Too little water means too little pressure at the arms.
- NEAR MISS — water in the tub that will not drain away — Standing dirty water is a drain fault, which is the opposite problem and a different code.
Likeliest causes first
- A tap partly closed or a kinked fill hose — First: the commonest cause by a wide margin, and visible in a minute behind the machine.
- A blocked inlet screen at the valve — Second: the mesh where the hose meets the machine catches grit and scale and closes gradually.
- The inlet valve or the aqua-stop in the hose — Last: a valve that has failed shut, or a safety device in the hose that has tripped and latched.
Check in this order
- Check the supply tap is fully open — Free, immediate, and it resolves a real share of these codes.
- Pull the machine out and look along the fill hose — A kink behind the appliance is invisible from the front and common after any move.
- Close the tap and inspect the inlet screen — Clogged mesh is owner-serviceable; the valve behind it is not.
Owner-safe steps
- Open the supply tap fully and check it stayed open — A valve knocked during other work is the single commonest cause.
About 5 min
- Straighten the fill hose along its whole run — Check where it meets the tap and where it passes behind the machine.
About 15 min
- STOP HERE — the inlet valve and sensing are inside the machine — Water and live circuits share that space.
Safety first
Safety
Unplug the appliance or switch off its breaker before removing any panel — a capacitor can hold a charge after the power is off. A dishwasher sits on a live circuit and a water supply at once: close the supply valve as well as the breaker, and expect standing water in the base of the tub.
When to call
Call when the tap is open, the hose is clear, the screen is clean and the code still stands. At that point the inlet valve or the safety device in the hose is the remaining suspect, all of which are inside the machine. Say what you have already ruled out — it keeps the visit short and stops you paying for the obvious twice.
Neighbouring codes — E3300 and E6001 sit beside E3400 and name overlapping hardware, so most checks here carry across. Read the two meanings side by side: where they differ in the part named, the order of the checks changes with them.
What this page does not cover
Generalized information: this reads E3400 as the shared Bosch dishwasher table records it, so it covers the model lines using that table and no others. Where a page exists for your family or model line, that one is the more specific answer — start there if your model is named. Not here: wiring colours, connector positions and part numbers, which differ by family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
