Robot lawnmower displays E4 and refuses to start; often occurs when placed outside the boundary wire.

Safety first: Turn the mower off and unplug the charging station from mains before touching any wiring.

• Check charging station LEDs: Most Hyundai bases have an indicator LED for loop status. If it is off or flashing, the loop is open or faulty.
• Inspect boundary wire connections: At the charging station, open the terminal cover and ensure both boundary wire ends are firmly clamped and not corroded. Trim and re-strip the wire ends if necessary.
• Walk the perimeter: Follow the boundary wire around the lawn looking for cuts, chew marks, or places where garden tools may have damaged it. Repair breaks using Hyundai-compatible waterproof wire connectors.
• Check for long splices: Too many or poor-quality splices can weaken the signal. Replace suspect joints with proper gel-filled connectors.
• Test base output: If the boundary wire is intact but E4 persists, the loop transmitter module in the Hyundai charging station may be defective and require replacement.