Robot mower stops and displays E3; often occurs when turning or on uneven ground.

Safety first: Turn OFF the main power before moving the mower.

• Check slope: Verify that the mower is used within the maximum slope specified in the Hecht manual (often around 20–35%). Avoid steep banks and edges.
• Inspect wheels and chassis: Look for ruts, holes, or obstacles that cause the mower to lean excessively. Level the ground or block off problematic areas with boundary wire.
• Reset on level ground: Place the mower on a flat, firm surface. Turn power OFF for 30 seconds, then ON. Start a manual mow cycle and observe if E3 reappears.
• Check for internal looseness: Gently shake the mower (power OFF). If you hear a loose module rattling, the tilt sensor bracket may have come loose and needs re‑securing.
• If E3 persists on level ground: The Tilt Sensor Module or main PCB input may be faulty. A service technician should open the housing, verify sensor mounting, and replace the tilt sensor if necessary.