When a Bosch dishwasher shows E21, the control has detected heat pump is blocked. The code narrows the diagnostic path but does not identify every cause by itself.
When a Bosch dishwasher shows E21, the control has detected heat pump is blocked. The code narrows the diagnostic path but does not identify every cause by itself.
Model compatibility: Bosch reuses codes across series and model years, so E21 may mean something different on another appliance or generation. Confirm this against your model’s documentation and record your full model number before acting.
Plain language
What this code means
The verified Bosch meaning for E21 is heat pump is blocked. Treat that wording as the technical anchor for this page. The displayed code narrows the system that needs attention, but the complete E-Nr and observed behavior are still important before a repair decision is made.
Signs
Symptoms you may notice
washing action may weaken or stop
heating performance can change
the cycle may interrupt
the warning may return after restart
Why it happens
Possible causes
restriction in the heat-pump/circulation path
heat-pump mechanical fault
related sensing or control condition
Important safety warning. Stop operation for leaking, overheating, electrical odor, or repeated breaker trips.
Seeing this code on your Bosch appliance?
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Request an appointment with your appliance model and symptom. We confirm a visit window, diagnose on site, then give a clear estimate. Approved work only proceeds after you agree.
Yes. You get an upfront estimate after diagnosis. No parts are ordered or installed until you approve the work.
Yes. We diagnose and repair Bosch refrigerators, dishwashers, washers, dryers, ovens, cooktops, and coffee machines common in LA and Orange County homes.
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