Robot lawnmower shows E5 and stops; often after hitting an obstacle or when nose is lifted.

Safety first: If the mower has overturned, switch off the main power immediately and set it upright on level ground.

• Relocate guide/boundary: Avoid deep holes, steep edges, or retaining walls where the Hyundai mower can tip. Adjust the boundary wire to keep it away from hazards.
• Check tilt sensor mounting: With power OFF and battery disconnected, remove the top cover. Locate the tilt sensor module (often a small board or sealed sensor fixed to the chassis). Ensure it is firmly screwed down and not loose.
• Inspect wiring: Confirm the tilt sensor connector is fully seated on the main control board and that no wires are pinched.
• Reset and test: Reassemble, place the mower on flat ground, and restart. If E5 appears immediately on level ground, the tilt sensor is likely defective and should be replaced.