Robot vacuum's side brush spins intermittently or not at all, but no specific error code is shown.

Safety first: Turn off the robot.

• Check brush attachment: Ensure the side brush is firmly screwed onto the motor shaft.
• Clean hub: Remove the brush and clear any hair or debris from the hub and shaft.
• Test rotation: With the robot on and cleaning, gently touch the side brush hub (without the brush) to see if the shaft spins consistently. If it stops easily, the motor may be weak.
• Replace module: If intermittent operation continues, replace the side brush motor module.

Warning: Keep fingers clear of the spinning shaft during testing.