Robot mower shows E09 and stops; may occur when reversing or turning.

Safety first: Switch OFF the mower and remove the battery or key. Support the mower securely before working near the wheels.

• Clean wheel hubs: Inspect the inner side of each drive wheel for encoder magnets or discs. Remove grass, mud, or metal filings that may interfere with the sensor.
• Check sensor gap: Ensure the hall sensor or optical sensor is correctly aligned and at the specified distance from the encoder disc or magnets.
• Inspect wiring: Follow the cable from the wheel motor to the main board. Look for pinched, cut, or loose wires, especially near pivot points.
• Swap test (if possible): On some Cedrus models, left and right wheel motor connectors can be swapped temporarily to see if the error moves sides, helping identify a bad motor vs. a bad board. Only do this if documented in the service manual.
• Persistent E09: If cleaning and reseating connectors do not help, replace the affected wheel motor assembly with integrated encoder or have the main board tested by a service center.