Robot vacuum reports a cliff sensor error or E06 and refuses to move, even on flat floors away from stairs.

Safety first: Turn off the robot and keep it away from actual stairs while testing.

• 1. Locate cliff sensors: On LG robot vacuums, cliff sensors are usually on the underside near the front edge, behind small clear or dark plastic windows.
• 2. Clean sensor windows: Use a soft, dry microfiber cloth to wipe each sensor window. For stubborn grime, lightly dampen the cloth with water or isopropyl alcohol and dry thoroughly.
• 3. Check for physical damage: Inspect the sensor windows for cracks, deep scratches, or missing pieces. If damaged, the sensor assembly or bottom cover may need replacement.
• 4. Test on light and dark surfaces: Place the robot on a light-colored hard floor and start cleaning. If the error persists, try a darker floor. Some sensors can be overly sensitive to certain surfaces; cleaning usually helps.
• 5. Advanced check: If cleaning does not help, remove the bottom cover and verify that the cliff sensor harness is firmly connected to the main PCB. If the harness is secure and the error remains, the cliff sensor board is likely faulty and should be replaced.