Bosch identifies E20 as an internal heater fault in the dishwasher heat pump.
What E20 means
Bosch identifies E20 as an internal heater fault in the dishwasher heat pump.
What you may notice
- The display or status light shows E20
- The dishwasher stops during a cycle
- A component-specific code appears
- A reset may clear it briefly
Most likely causes
- 01A pump or heater circuit is not responding
- 02A solenoid or relay has failed
- 03A connector or harness is damaged
- 04A control module detected an internal fault
- 05The affected component needs model-specific testing
Safe checks, in order
Start with the simplest non-invasive check. Stop as soon as the error clears; repeated resets can hide a condition without correcting it.
Record the code
Photograph the display or count the full flashing pattern.
Cancel safely
Allow any drain routine to finish and check for visible water.
Reset once
Switch the dishwasher circuit off for 30 seconds, then restore power.
Stop if it returns
Do not remove the dishwasher or access internal components.
Know where to stop
Dishwashers combine water, heat, and line voltage. Internal component checks belong to a qualified technician.
When to call a technician or support
Contact the manufacturer or an appliance technician when the component code returns after one reset.
When you call, have the exact product model, the complete code or light pattern, and when it appeared.
Where this information came from
We use the manufacturer's current published guidance as the starting point, then organize it into a safer, beginner-friendly sequence.
Bosch Owner Support — dishwasher error codes Source last checked August 18, 2026. Manufacturer instructions and model manuals take priority over this independent summary.