Robot mower stops and displays E03 shortly after leaving the charging station or when encountering uneven ground.

Safety first: Turn OFF the main power and remove the battery connector before opening the housing.

• Check operating conditions: Ensure the mower is used on slopes within LawnMaster's specified gradient (typically 20–35%). Remove from steep banks or holes where it may tip.
• Inspect for physical tilt: Make sure the mower is sitting level on all wheels. Check for stuck wheels or objects under the chassis causing it to lean.
• Clean the underside: Built-up grass can interfere with tilt sensing. Carefully tip the mower on its side (blades away from you, power OFF) and clean the deck and wheel wells.
• Locate the tilt sensor: Inside the upper housing, find the small tilt sensor module (often a small PCB or sealed sensor fixed to the chassis). Ensure its screws are tight and the module is not loose.
• Check wiring: Follow the tilt sensor harness to the main control board. Confirm the connector is secure and wires are not damaged.

If E03 appears even on level ground and the wiring is intact, the tilt sensor module may need replacement. In rare cases, the main control board tilt input is defective and requires professional service.