Robot mower shows E7 and stops; one or more wheels may not be turning.

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

Steps:

• 1. Inspect wheels: Check both rear drive wheels and front caster(s) for stones, twine, or compacted grass. Remove any obstructions.
• 2. Check wheel rotation: Turn each wheel by hand. They should rotate with some gearbox resistance but without grinding or locking. A locked wheel indicates gearbox or motor failure.
• 3. Clean wheel housings: Remove wheel covers (if fitted) and clear mud and grass from around the axle and gearbox output.
• 4. Examine wheel hubs: Ensure the wheel is firmly attached to the drive shaft. Tighten or replace the hub if stripped.
• 5. Electrical test: With the mower open and battery disconnected, unplug the suspect drive motor from the main PCB. Measure motor resistance and compare with the other side. A large difference suggests a faulty motor.
• 6. Replace drive motor/gearbox: If the motor is burnt, noisy, or seized, replace the complete drive motor and gearbox unit for that side.

If E7 persists on both sides with good motors, the motor driver circuitry on the main PCB may be defective and should be checked by a technician.