The E440 error on your Bosch Dishwasher means the appliance has detected a problem with water temperature sensing or heating during the wash cycle. This usually stops the cycle partway through and can often be fixed without calling an engineer.
| Error code | E440 |
|---|---|
| Meaning | Fault in the water temperature sensor or heating circuit |
| Severity | Medium — dishwasher may still run but won't heat water properly |
| Time to fix | 15–40 minutes |
| Tools needed | Multimeter (optional), screwdriver |
What the E440 error means
E440 is triggered when the dishwasher's control board doesn't receive the expected signal from the temperature sensor (thermistor) or heating element circuit. This can happen if a wire has loosened, the sensor has failed, or the heating element itself is faulty. Some Bosch models will display this as a flashing light pattern rather than a text code, depending on the panel.
Common causes
- Faulty or dislodged temperature sensor (thermistor)
- Loose or corroded wiring connections at the sensor or heater
- Failed heating element unable to reach target temperature
- Limescale buildup interfering with sensor readings
- Control board fault (less common, but possible after a power surge)
- Blocked water inlet reducing flow needed for accurate heating
How to fix the E440 error
- Power cycle the dishwasher: Turn off at the wall, wait 2 minutes, then restart. This clears temporary sensor glitches.
- Check for limescale: Run a descaling rinse cycle, especially if you're in a hard water area, since mineral buildup can throw off temperature readings.
- Inspect wiring connections: With the machine unplugged, remove the lower kick panel and check that connectors to the heating element and sensor are firmly seated.
- Test the sensor with a multimeter: Check resistance against Bosch's spec sheet for your model; replace the sensor if readings are outside range.
- Inspect the heating element: Look for visible damage or continuity failure; a faulty element usually needs professional replacement.
- Call an engineer if the fault persists: If steps above don't clear E440, the control board may need diagnostic testing.
FAQ
Can I still use my dishwasher with an E440 error showing?
You can try, but dishes may not be washed at the correct temperature, so it's best to fix the fault first.
Is E440 dangerous or a fire risk?
Not typically, but a failing heating element should be checked promptly to avoid further damage to the appliance.
Do I need a professional to fix this?
Basic checks like power cycling and descaling are safe to do yourself. Sensor or heating element replacement is best left to a qualified engineer.
If you're dealing with faults across other Bosch appliances at home, guides like Bosch Drill Won'T Start: Causes and How to Fix It or Bosch Drill Overheating During Use: Causes and How to Fix It follow the same troubleshooting logic — check power, connections, then internal components. Similarly, if a Bosch drill has been giving you trouble alongside kitchen appliances, see Bosch Drill Chuck Won'T Tighten: Causes and How to Fix It and Bosch Drill Battery Not Connecting: Causes and How to Fix It for related fixes.
