What E04 means on your Bosch dishwasher
Error code E04 indicates that the flow sensor (water turbine) in your Bosch dishwasher is not detecting adequate water movement through the wash system. This sensor monitors water circulation during the wash and rinse cycles. When it fails to register pulses, the control board interprets this as insufficient water flow and halts the cycle to prevent the circulation pump from running dry.
Symptoms
- Dishwasher fills with water but stops shortly after the wash cycle begins
- The circulation pump may run but dishes remain dirty
- Intermittent E04 errors that come and go between cycles
- Unusual humming or quieter-than-normal pump operation
Common causes
- Blocked or dirty flow sensor — food debris, glass fragments, or mineral buildup can obstruct the turbine impeller
- Failed flow sensor — the hall-effect sensor or turbine mechanism wears out over time
- Clogged spray arms — restricted spray arm nozzles reduce water return flow past the sensor
- Circulation pump issue — a weak or failing pump may not generate enough flow to trigger the sensor
Troubleshooting steps you can try
- Clean the filters — remove and thoroughly clean the mesh filter, micro-filter, and coarse filter at the bottom of the tub. A clogged filter restricts water flow throughout the system.
- Inspect the spray arms — remove both spray arms and clear any debris from the nozzle holes using a toothpick. Check that the arms spin freely.
- Check for debris in the sump — look inside the sump area (below the filter assembly) for glass shards, food particles, or foreign objects.
- Power cycle — turn off the dishwasher at the breaker for 5 minutes, then restart with a clean load.
When to call a technician
If cleaning the filters and spray arms doesn’t resolve E04, the flow sensor itself likely needs replacement. The sensor is mounted in the sump assembly and requires partial disassembly of the base to access. A technician can also test the circulation pump’s flow rate to rule out pump degradation. Running the dishwasher repeatedly with E04 active can stress the circulation pump. Codes may vary by model generation and series.
Need help? Schedule Bosch Dishwasher repair with a certified technician, or contact our team for a free diagnosis consultation.
