What Bosch ER05 error means on your washer
The Bosch ER05 error code indicates a fault with the water temperature sensor (NTC thermistor). This sensor monitors the water temperature throughout the wash cycle, allowing the control board to heat the water to the correct temperature for the selected program. ER06 indicates the same type of fault and the two codes are often grouped together. When the NTC sensor fails, the washer cannot safely control water temperature.
Symptoms
- The washer stops mid-cycle and displays ER:05 or ER:06
- Water temperature is inconsistent — clothes washed in cold when hot was selected, or vice versa
- The heater may not activate at all (the board won’t heat without reliable temperature feedback)
Common causes
- Failed NTC sensor — the thermistor has degraded and reads outside the expected resistance range
- Loose wire connection — the sensor plug on the heater assembly or main board has come loose from vibration
- Damaged wire harness — the sensor wires can be pinched or damaged during installation or maintenance
Troubleshooting steps you can try
- Power reset — unplug the washer for 5 minutes. A temporary sensor glitch can clear with a reset.
- Check wire connections — if you can access the rear panel, inspect the NTC sensor connector on the heater assembly for secure seating. Consult Bosch washer support for your model’s service manual.
When to call a technician
The NTC sensor is typically mounted on or near the heater element in the sump area. A technician will measure the sensor resistance — at room temperature it should read approximately 5–10 kΩ depending on the model. Schedule Bosch washer service for ER05/ER06 diagnosis. Our Bosch washer repair technicians carry NTC sensors for common models. See all Bosch washer error codes.
