Dishwasher displays E21 and may stop during wash; circulation pump may hum but not run properly.

Safety first: Disconnect power and close the water tap. Allow the machine to cool.

• Clean sump and filters: Remove all filters and inspect the sump for broken glass, bones, or other debris that could reach the pump.
• Access circulation pump: Lay the dishwasher on its back and remove the base cover. Locate the circulation pump attached to the sump.
• Inspect impeller: Remove the pump from the sump (release clamps or twist lock). Check the impeller for foreign objects and limescale. Clean thoroughly.
• Check bearings: Rotate the impeller by hand. It should spin smoothly. Grinding or stiffness indicates worn bearings and the pump should be replaced.
• Inspect wiring: Ensure the pump connector is secure and wires are not damaged.
• Reassemble and test: Refit the pump and base, restore power and water, and run a test cycle to confirm that E21 is cleared.