Dishwasher shows E18; unit may drain immediately after filling or not retain water.

Safety first: Disconnect power before working behind the dishwasher.

• Verify drain hose routing: Ensure the drain hose rises to the required height (usually underside of countertop) before connecting to the sink drain or disposer. Install a high loop or air gap as specified by Summit.
• Check for backflow: Inspect the sink drain and disposer for clogs that could cause water to flow back into the dishwasher.
• Inspect check valve: Access the sump from inside the tub and locate the drain check valve. Ensure it moves freely and is not stuck open. Replace if worn or damaged.
• Test operation: After correcting hose routing and components, run a cycle and confirm the tub maintains proper water level without immediate draining.