The E251 error on your Bosch Dishwasher means the machine has detected a problem with its drainage system — usually that water isn't being pumped out fast enough or at all. This is often caused by a blockage in the filter, drain hose, or non-return valve, and can usually be fixed without calling an engineer.
| Error code | E251 |
|---|---|
| Meaning | Drainage fault — the dishwasher cannot clear water within the expected time frame |
| Severity | Medium — the dishwasher will usually stop mid-cycle and may leave standing water inside |
| Time to fix | 15–40 minutes |
| Tools needed | Towels, a bowl or cup, basic screwdriver (optional) |
What the E251 error means
Bosch dishwashers monitor how quickly water drains out of the tub during and after a wash cycle. If the sensor detects that drainage is taking too long, or isn't happening at all, it throws the E251 code and pauses the programme to protect the pump and motor from damage.
This is one of the more common Bosch dishwasher faults and is rarely due to a major electrical or mechanical failure. In most cases, something physical is blocking the flow of water out of the machine.
Common causes
- Food debris or a broken piece of glass/plastic blocking the filter basket
- A kinked, trapped, or partially blocked drain hose
- A clogged non-return (check) valve where the hose connects to the sink or drain pipe
- A faulty or worn-out drain pump that can no longer move water efficiently
- The sink waste or garbage disposal connection being blocked, forcing water back into the dishwasher
- An airlock in the drain hose caused by incorrect installation height
How to fix the E251 error
- Turn off and unplug the dishwasher — Always disconnect power before checking any internal parts to avoid electric shock.
- Remove and clean the filter — Take out the mesh and coarse filters at the bottom of the tub and rinse away any trapped food, glass fragments, or grease under running water.
- Check the drain hose for kinks or blockages — Pull the dishwasher out slightly and inspect the hose for tight bends, trapped debris, or damage. Straighten or clear as needed.
- Inspect the sink connection — If the hose connects near a sink or waste disposal unit, make sure that pipe isn't blocked, as backed-up water will trigger E251 even if the dishwasher itself is fine.
- Manually bail out standing water — Use a cup or sponge to remove any leftover water from the tub before restarting, so the sensor doesn't immediately re-trigger the fault.
- Run a test cycle — Power the dishwasher back on and run a short rinse cycle to confirm water drains fully and the error doesn't return. If it does, the drain pump may need professional replacement.
FAQ
Can I still use my dishwasher with an E251 error showing?
It's best not to. The machine will likely pause mid-cycle again, and running it repeatedly with a blocked drain can strain the pump motor.
Does E251 mean the drain pump is broken?
Not always. Most cases are caused by simple blockages in the filter or hose. If cleaning these doesn't resolve it, the pump may be faulty and require replacement.
How do I stop E251 from happening again?
Clean the filter basket every one to two weeks, scrape large food scraps off plates before loading, and check the drain hose periodically for kinks or buildup.
