Robot mower displays E13 and stops; often after hitting a hard obstacle or curb.

Safety first: Turn OFF the mower and disconnect the battery before inspecting the chassis.

• Inspect for visible damage: Check the front and sides of the mower for cracks, bent plastic, or misaligned panels.
• Check impact sensor strip: Some LawnMaster models use a flexible sensor strip around the perimeter. Ensure it is not torn, folded, or permanently compressed.
• Verify mounting points: Tighten any loose chassis screws or brackets that may cause false impact readings.
• Inspect wiring: Follow the impact sensor cable to the main control board and ensure connectors are secure.

Clear the error and test in an open area away from obstacles. If E13 reoccurs without impact, the impact sensor assembly may need replacement. Severe frame damage should be assessed by a service center.