Robot lawnmower shows E12 and stops; often after hitting a hard obstacle or curb.

Safety first: Switch OFF the mower and remove power from the charging station.

• Inspect front wheel: Check the front caster or support wheel for free rotation. Remove grass, mud, or stones that may prevent it from turning or swiveling.
• Check mounting arm: Ensure the front wheel arm is not bent upward, causing the mower to think it is lifted. Gently straighten or replace if damaged.
• Clean sensor area: If the model uses a sensor near the front wheel, clean around it with a brush and compressed air. Make sure any mechanical lever can move freely.
• Test on level ground: Place the mower on a flat surface and restart. If E12 reappears immediately, the front wheel sensor or its wiring may be defective.
• Replace sensor if needed: Replace the front wheel sensor assembly or bracket if physical damage is evident or the error cannot be cleared.