What E:21 Means
E:21 says the heat pump is turning against an obstruction, or not turning at all because something is jammed in it. Bosch's action for this row is a single line, remove the debris or obstruction from the heat pump, which tells you this is a mechanical blockage rather than an electrical failure. Glass fragments, fruit stones and small bones are the usual finds.
Common Causes of E:21
- Hard debris drawn into the pump past the filter
- Glass fragment lodged against the impeller
- Filter left out or fitted incorrectly, letting debris through
🔧 One Safe Check You Can Try
Twist out the lower filter assembly and rinse it, then look into the sump beneath it with a torch for anything obviously hard and out of place. Do not reach into the pump opening itself, which is where broken glass ends up.
⚠ Why You Shouldn't Go Further Than That
- The most common obstruction in a dishwasher pump is broken glass, and clearing it by feel is how people end up with tendon injuries.
- The pump is a live-voltage motor, so it has to be fully isolated before anything goes near the impeller.
- Debris pushed further in rather than lifted out turns a blockage into a seized motor, which is a much larger bill.
- Bosch reaches the heat pump from below with the machine drawn out, and tilting a built-in dishwasher to get underneath it puts weight on the hoses at the back.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.