Robot mower shows E8 and stops near obstacles, sometimes after bumping into them

Safety: Switch OFF main power and place the mower on a bench or clean surface.

• Check bumper movement: Gently press the front bumper. It should move freely and spring back. If it sticks, inspect for trapped grass or dirt.
• Clean bumper area: Remove debris from the gap between bumper and chassis using a soft brush.
• Inspect springs and guides: Look for broken or dislodged bumper springs or guide pins. Re-seat or replace as needed.
• Sensor wiring: If accessible, check the bumper sensor switch or strip wiring harness for loose connectors.
• Reset and test: Power ON, clear E8, and gently push the bumper by hand to confirm it triggers and releases correctly.

If the bumper appears mechanically sound but E8 persists, the bumper sensor assembly may be defective and should be replaced.