Dishwasher stops and displays A04; may occur shortly after starting a cycle, often related to water level issues.

Safety first: Unplug the appliance and close the water tap.

• Check for overfilling: Open the door mid-cycle (if safe) and see if the water level is above the filter area. Excessive water suggests an overfill condition.
• Inspect and clean pressure system: Access the pressure switch (usually mounted on the side wall or base) and its thin rubber hose leading to the sump or side chamber. Remove the hose and blow through it to ensure it is clear. Clean any sludge or grease from the pressure chamber connection at the sump.
• Check the pressure switch contacts: Gently blow into the switch port; you should hear clicks as the diaphragm operates. Use a multimeter to verify that the contacts change state when pressure is applied.
• Inspect inlet valve: If the tub continues to fill even when the machine is off, the water inlet valve may be stuck open and must be replaced immediately to prevent flooding.
• Reset and test: After cleaning and reassembly, restore power and water, then run a short cycle to confirm that the error is cleared.

If A04 recurs, the pressure switch or control board may require professional diagnosis and replacement.