Dishwasher stops with F4, often after attempting to drain; water may remain in the bottom.

Safety first: Disconnect power and close the water tap before servicing.

• Clean filters and sump: Remove and clean all filters. Check the sump area for food, labels, or glass obstructing the pump inlet.
• Access drain pump: Tilt the dishwasher carefully and remove the bottom panel (if present). Locate the drain pump on the sump. Remove the pump (usually held by a bayonet fitting or screws) and check for debris in the impeller housing.
• Check pressure system: On many Bauknecht models, a small pressure chamber and hose connect the sump to a pressure switch. Remove the thin hose and blow through it to clear grease or sludge. Clean the chamber with hot water.
• Inspect drain hose run: Ensure the hose has a smooth upward loop and no sags where debris can collect. Flush with hot water.
• Re-test: Reassemble, restore power, and run a drain or short cycle. If F4 persists and the pump runs freely, the pressure switch or control board may need replacement.