Robot mower shows E11 and stops when encountering obstacles; bumper feels unresponsive.

Safety first: Turn OFF the mower and wear gloves when handling it. Keep it on a stable surface.

• Check bumper movement: Gently press the front bumper at several points. It should move freely and return under spring tension. Free any trapped grass or debris.
• Inspect for damage: Look for cracks, warping, or impact damage that may prevent the bumper from moving or actuating the internal switches.
• Clean sensor area: If the mower uses a sensor strip, wipe it clean with a dry cloth to ensure proper operation.
• Internal check: If accessible, open the front housing and verify that the bumper switch or sensor board is firmly mounted and that the connector is secure.
• Replacement: If the bumper does not click or the sensor tests open‑circuit, replace the bumper switch assembly or bumper sensor board with a Cedrus‑approved part.