Robot vacuum stops and displays E5, often when approaching stairs or dark carpets.

Safety first: Turn the robot OFF and keep it away from stair edges while testing.

• Step 1 – Clean cliff sensors: Turn the robot upside down. Locate the downward-facing cliff sensors (usually 3–6 small windows along the front underside). Clean each window with a soft, dry cloth or cotton swab. Remove any dust buildup.
• Step 2 – Test on light floor: Place the robot on a flat, light-colored surface away from edges. Turn it ON and start a cleaning cycle. If E5 disappears, the issue was likely dirt or surface contrast.
• Step 3 – Avoid reflective/dark surfaces: Very dark or glossy floors can confuse cliff sensors. Test on a different area to confirm. If the robot only errors on certain surfaces, consider using virtual barriers or boundary strips.
• Step 4 – Inspect wiring: If E5 appears immediately on any surface, remove the bottom cover and check the cliff sensor board connections to the mainboard. Reseat the connectors.
• Step 5 – Replace sensor module: If one or more sensors are physically damaged or still report errors after cleaning and reseating, replace the Medion cliff sensor module or individual IR sensor board.