Robot mower shows E08 and stops; often associated with erratic movement or inability to drive straight.

Safety first: Turn OFF the mower and disconnect the battery before removing wheels or covers.

• Remove drive wheels: Take off the wheel caps and retaining nuts, then pull the wheels off to access the encoder discs or magnets on the motor shafts.
• Clean encoder components: Use a soft brush and dry cloth to remove grass, mud, and metal filings from the encoder disc or magnet and the sensor area.
• Check alignment: Ensure the encoder disc is not cracked or wobbling and that the magnet (if used) is firmly attached to the shaft.
• Inspect sensors: Verify that the hall sensors or optical sensors are securely mounted and positioned close enough to the disc/magnet as per LawnMaster specifications.
• Check wiring: Follow the encoder sensor wires back to the main control board, ensuring no cuts, pinches, or loose connectors.

After cleaning and reassembly, clear the error and test drive the mower. If E08 persists on one side, replace that wheel encoder sensor assembly. If both sides fail, the main control board's encoder input circuitry may be defective.