What Bosch E20 error means on your dishwasher
Error code E20 signals a fault in the heating circuit. The control board has determined that the water is not reaching the target temperature within the expected time. On newer Bosch models with heat pump drying, E20 can also indicate a heat pump motor or compressor fault. E20 is closely related to E19 (heat exchanger) and E21 (heat pump) — all three codes relate to the thermal management system. If you encounter the bosch e20 error, professional Bosch dishwasher repair may be needed.
Symptoms
- Wash cycles run significantly longer than normal as the dishwasher waits for heating
- Dishes come out cold and with food residue
- Drying performance drops — dishes are wet after the cycle ends
- The display shows E20 during the wash or dry phase
Common causes
- Failed heating element — the flow-through heater that raises water temperature during the wash phase has an open circuit
- Heat pump compressor failure — on models with CrystalDry or heat pump drying, the compressor motor has seized or lost refrigerant
- NTC sensor drift — the temperature sensor reads incorrectly, preventing the control board from activating the heater at the right time
- Limescale buildup on heater — heavy calcium deposits insulate the heating element, drastically reducing its efficiency
See all Bosch dishwasher error codes for related fault codes and diagnostic steps.
Troubleshooting steps you can try
- Run a hot water flush — before starting the dishwasher, run the kitchen hot tap until the water is hot. This gives the heater a head start and can prevent timeout-based E20 triggers.
- Descale the dishwasher — run an empty cycle with a commercial dishwasher descaler or 2 cups of white vinegar on the hottest setting. Limescale on the heater is a leading cause of slow heating.
- Reset — turn off the breaker for 5 minutes. Temporary sensor glitches can trigger E20 once.
- Check Bosch support — visit Bosch’s official dishwasher support page for model-specific troubleshooting guides and tech notes.
When to call a technician
If E20 recurs after descaling and resetting, the heating element or heat pump requires professional diagnosis. A technician will measure the heater resistance (typically 20–30 ohms for a working flow-through heater) and check the heat pump refrigerant circuit if applicable. Heater replacement is a common repair; heat pump replacement is more involved and costly. Codes may vary by model generation and series. Schedule a certified Bosch technician for fast, reliable diagnosis and repair.
