Robomow shows E3 and refuses to start mowing, often after being moved or bumped.

Safety first: Turn the main power switch OFF before lifting or tilting the mower. Never work near the blades while powered.

• Place mower on level ground: Set the mower on a flat, firm surface within the working area. Ensure all wheels are on the ground and not on a slope or obstacle.
• Power cycle: Turn the main switch OFF for 30 seconds, then ON. Clear the error and attempt a manual start without lifting the mower.
• Check for stuck tilt mechanism: Gently press down on each corner of the mower to ensure the chassis moves freely and returns. Debris wedged between the chassis and wheels can falsely trigger tilt; remove any stones, branches, or packed grass.
• Inspect lift sensor (if accessible): On many Robomow models, a lift sensor is integrated near the front handle or chassis. Check that the handle is fully seated and not partially lifted. If there is a visible micro‑switch, ensure it is not bent or broken.
• Check wiring: If comfortable opening the top cover (per manual), inspect the tilt/lift sensor connector on the main board. Reseat the connector.
• Persistent E3: A defective tilt/lift sensor or main board input is likely. Because this is a critical safety device, replacement should be done by a qualified technician.