Robot mower displays E6 and refuses to start; often after a collision or when the front bumper is stuck.

Safety first: Turn OFF main power before manipulating the bumper or opening covers.

• Check bumper movement: Gently press and release the front bumper. It should move freely and return to its original position. If it feels stuck, inspect for trapped grass, twigs, or stones and remove them.
• Clean bumper gap: Use a brush or compressed air to clean the gap between the bumper and chassis. Avoid high‑pressure water.
• Inspect springs and guides: If accessible, check that the bumper return springs are intact and correctly seated. Replace damaged Bumper Spring Kit if necessary.
• Check bumper switch: Open the top cover (with power OFF) and locate the Bumper Switch Assembly or sensor strip. Ensure the connector is firmly plugged into the main board and wires are not broken.
• Test operation: Power ON, clear the error, and gently press the bumper while the mower is in test mode (if available). If E6 persists or the mower does not detect bumper presses, replace the bumper switch assembly.