Robot mower shows E18 and stops; often related to rain sensor or weather protection.

Safety first: Turn OFF main power before cleaning the sensor area.

• Check weather conditions: If it is raining or the mower is wet from sprinklers, allow it to dry completely before restarting. The rain sensor is designed to stop mowing in wet conditions.
• Clean sensor: Locate the Rain Sensor Pad (often on the top housing). Wipe it gently with a dry cloth to remove dirt or algae.
• Inspect wiring: Open the housing and trace the rain sensor cable to the Main Control Board. Ensure the connector is secure and there are no signs of corrosion.
• Test in dry conditions: After drying and cleaning, restart the mower. If E18 appears immediately in dry weather, the sensor may be shorted and should be replaced.