Dishwasher shows U12 and beeps when trying to start

• Close door firmly: Ensure the door is fully closed until it clicks, then press Start again.
• Check for obstructions: Make sure racks and utensils are not preventing full closure.
• Inspect latch: If U12 recurs, inspect the latch and strike for wear or misalignment and adjust or replace as needed.

Persistent U12 with a fully closed door indicates a door switch or latch fault.