Display shows “Error 5 – Collision sensor problem” and mower stops shortly after starting.

Safety first: Press STOP, switch OFF the mower, and remove the key (if present) before inspecting the bumper.

• Check bumper movement: Gently press the front bumper in and release. It should move freely and spring back without sticking.
• Remove debris: Clear any grass, twigs, or dirt trapped between the bumper and chassis that could prevent proper movement.
• Inspect springs and mounts: Look underneath the front cover for broken or dislodged bumper springs or plastic guides. Re-seat or replace as needed.
• Check collision switch: If accessible, inspect the collision microswitch or sensor module for damage or water ingress. Ensure its connector is firmly seated on the main PCB.
• Restart test: After cleaning and reassembly, place the mower on the lawn and start a short test run, gently pushing the bumper to confirm it triggers and releases correctly.

If Error 5 continues and the bumper is mechanically free, the collision sensor or main board may be defective and require replacement.