Dishwasher stops and displays F4; water remains in the bottom of the tub and does not drain.

Safety: Turn off power and close the water supply. Be prepared for water spillage when opening the sump or hoses.

• Clean internal filters: Remove the lower rack and filter assembly. Clean the coarse and fine filters thoroughly. Check for glass, bones, or food debris in the sump area.
• Inspect the drain pump impeller: With filters removed, locate the drain pump access (often a small cover in the sump). Remove the cover and check the impeller for obstructions such as glass shards, seeds, or labels. Rotate the impeller gently to ensure it moves freely.
• Check the drain hose: Follow the drain hose from the dishwasher to the sink drain or garbage disposer. Ensure it is not kinked or crushed. Disconnect it at the sink end and flush with water to confirm it is clear.
• Verify disposer knockout: If the dishwasher was recently installed to a new garbage disposer, confirm the disposer’s dishwasher knockout plug has been removed.
• Test a short cycle: Reassemble, restore power, and run a short program. If F4 returns and the pump hums but does not move water, the Asko drain pump motor is likely faulty and should be replaced.