Match the symptom, then work through the safe checks.
1. What best matches what you observe?
2. Complete only the checks that are safe for you.
Show stop conditions
- Burning electrical smell
- Motor or wiring becomes hot
- Breaker trips or movement is seized
Likely causes
- The heat pump's internal heater circuit has developed a fault
- The heat-pump assembly is not operating within the expected electrical range
- A wiring or connection problem is affecting the heat-pump heater circuit
- The control continues to detect the heater fault after a reset
Quick checks, in order
Reset power for 30 seconds
Switch the dishwasher off at the breaker for about 30 seconds, then restore power and retry once.
Note whether E20 returns
If the code reappears, stop repeated resets. Bosch identifies E20 as an internal heat-pump heater fault rather than a user-cleanable filter condition.
Do not open the heat-pump assembly
The heater and pump are internal electrical components. Do not remove panels or test energized parts unless qualified.
Arrange Bosch service if persistent
A recurring E20 needs model-specific electrical diagnosis of the heat-pump heater circuit and related wiring/control components.
Does E20 clear after the single Bosch power reset?
Monitor the next cycle. If the code returns, treat it as an intermittent heat-pump heater fault and arrange service.
The internal heater circuit remains the primary Bosch-defined fault area. Avoid repeated cycling and arrange model-specific diagnosis.
Stop using the appliance, disconnect power if safe, and arrange professional service before further operation.
Stop and get qualified help when
- Burning electrical smell
- Motor or wiring becomes hot
- Breaker trips or movement is seized
Official support and model manuals
Use the full model number from the rating label. The manufacturer manual is the deciding reference when codes differ by region or product family.
Frequently asked questions
What does Bosch dishwasher E20 mean?
Bosch identifies E20 as a heat-pump internal heater fault/error on supported dishwasher models.
Is Bosch E20 the same as E21?
No. Bosch lists E20 as an internal heat-pump heater fault, while E21 means the heat pump is blocked. Both may require service if a power reset does not clear the code.