Robot vacuum reports a side brush error or E04; side brush does not spin or spins intermittently.

Safety first: Turn off the robot and remove it from the dock before servicing the side brush.

• 1. Remove side brush: Flip the robot over. Use a small screwdriver to remove the screw holding the side brush (if present), then pull the brush straight off the shaft.
• 2. Clean hub and shaft: Remove hair and debris from around the shaft and under the brush hub. Use tweezers for tight areas.
• 3. Inspect brush hub: Check the plastic hub for cracks or rounding where it mates with the motor shaft. If it spins freely without gripping the shaft, replace the side brush.
• 4. Test motor rotation: With the brush removed, gently spin the motor shaft with your fingers. It should turn smoothly with slight resistance. If it is seized or very rough, the motor is likely defective.
• 5. Reinstall and test: Refit the side brush securely and start a cleaning cycle. Observe whether the brush spins consistently.
• If the error persists with a new brush and clean hub, the side brush motor or its driver circuit on the main PCB may need replacement by a technician.