Washer-dryer combo intermittently stops, beeps, and shows F11; may not respond to buttons.

Safety first: Unplug the appliance before accessing any control boards.

Step-by-step checks:

• 1. Access controls: Remove the top panel and, if necessary, the console panel to expose the main control board (CCU) and user interface (UI) board.
• 2. Reseat connectors: Identify the communication harness between the CCU and UI (refer to the tech sheet if available). Unplug and firmly reconnect each connector several times to wipe oxidation from the pins.
• 3. Inspect harness: Look for pinched, broken, or discolored wires. Replace the harness if any damage is found.
• 4. Check for moisture: Ensure there is no condensation or detergent residue on the boards. Dry gently with a hair dryer on cool if needed.
• 5. Board evaluation: If F11 persists, one of the boards is likely failing. Visual signs like burnt components or corrosion indicate replacement is needed. Start with the more commonly failed board per your model's service literature.