Robot mower shows E18 and stops when entering narrow passages or complex garden areas.

Safety first: Turn OFF the mower before cleaning or adjusting sensors.

• Clean sensor faces: Wipe the ultrasonic sensor openings on the front of the mower with a soft, damp cloth to remove dirt and grass.
• Check for damage: Inspect the sensor housings for cracks or signs of water ingress.
• Verify alignment: Ensure the sensor bracket is not bent and that sensors point straight ahead as designed.
• Inspect wiring: Open the housing and check the ultrasonic sensor harness and connector at the main board.

If E18 persists after cleaning and inspection, the ultrasonic sensor module may need replacement. In rare cases, the main board input circuitry is at fault.