Robot mower displays E11 and stops; often occurs when operating in very hot or very cold conditions.

Safety first: Turn OFF the mower and allow it to cool or warm to ambient room temperature before further troubleshooting.

• Check environment: Do not operate or charge the mower in direct midday sun or below the minimum temperature specified by LawnMaster. Move the charging station to a shaded, dry area.
• Allow cooling: If the mower feels hot, let it rest in a cool, ventilated place for at least 1 hour, then try again.
• Inspect battery placement: Ensure the battery pack is correctly seated in its compartment and that any thermal pads or insulation are in place as designed.
• Check sensor wiring: The battery temperature sensor is often integrated into the pack or connected via a small harness. Inspect for loose or damaged wires.

If E11 appears even at moderate temperatures, the temperature sensor inside the battery pack or on the main board may be defective. Replace the battery pack first; if the fault persists, the main control board may require replacement.