Bosch Dishwasher error code E20
Heat pump internal heater fault
Quick answer
On Bosch Dishwasher (2000s onward), E20 is a fault. It means heat pump internal heater fault. A first thing to check: Heating element failed open or shorted.
- Applies to
- Bosch Dishwasher
- Bosch dishwasher codes · Dishwasher · 2000s onward
- Type of code
- Fault
- Urgency: Needs attention soon
- First safe check
- Unplug the machine and look for visible scale on the element through the sump.
What E20 means on this model
The heater inside the heat pump chamber is not operating. Bosch describes a breaker reset for thirty seconds as the first step, and a code that returns after that is a genuine heater fault rather than a control that lost its state.
Symptoms you will notice
- Code appears partway through the wash
- Dishes come out with food that needs a second run
- Water is cold when the machine reports a heater fault
- Cycle takes much longer than normal
Common causes
The code tells you what the control detected, not which part failed. These are the causes we see most often, roughly in order of likelihood:
- Heating element failed open or shorted
- Circulation pump that moves water past the element not running
- Thermistor in the water path reading incorrectly
- Relays or triacs on the main board failing to energise the heater
- Heater energising when it should not, which is what the over-temperature part of the fault means
- Hard water scale on the element cutting its heat output
What you can safely check
These are homeowner-level checks. None of them need you to open a live electrical compartment or work on gas.
- Unplug the machine and look for visible scale on the element through the sump.
- Confirm the machine is on its own circuit, since a shared circuit starves a heater.
- Check that the water filter and the spray arm are not so blocked that water is barely moving past the heater.
Do not do these
- ×Do not test an element for continuity with the machine plugged in.
- ×Do not bridge the heater circuit to force heat. The thermistor is the only thing limiting the temperature.
When to call a technician
Book a technician, do not keep resetting it
This fault will not clear on its own. Every power cycle gives the control one more failed attempt, and repeated attempts are what turn a cheap part replacement into a seized or contaminated system.
- If the appliance has stopped mid-cycle, is making a noise you have not heard before, or smells burnt, stop reading here and call. Those are symptoms of something the fault code does not describe well enough.
A thermistor or a board relay is a moderate repair. Element and pump replacement on a built-in model is a technician job.
What it costs to fix
Parts
Heating element $60 to $160. Circulation pump $70 to $180. Thermistor $20 to $60. Board relay $30 to $90.
Labor
One and a half to three hours depending on how much of the sump comes apart.
DIY or technician
A thermistor or a board relay is a moderate repair. Element and pump replacement on a built-in model is a technician job.
Typical US part and labor ranges, 2026. They vary by region, model and contractor, so treat them as a planning figure, not a quote.
Scope of this code
- Code table
- Bosch dishwasher codes
- Models in scope
- Bosch Dishwasher, 2005 onward
- Checked
- Confirm on your own unit
- Find the model number on the data plate, then check this code in the service manual for that model. Manufacturers revise code tables between model years, and a revised board can renumber a fault.