Robot vacuum reports C1 and will not start cleaning; often announces a side brush error.

Safety first: Turn the robot OFF and remove it from the charging dock. If possible, remove the battery or ensure the power switch is OFF before working underneath.

• Inspect the side brush: Flip the robot over. Gently pull off the side brush (usually secured with a screw or push-fit). Remove hair, string, and debris from the bristles and the hub.
• Clean the side brush shaft: Check the shaft where the brush mounts. Use tweezers to pull out wrapped hair. Wipe with a dry cloth.
• Check for free rotation: With the brush removed, spin the motor shaft gently with your fingers. It should turn smoothly without grinding or sticking.
• Reinstall and test: Refit the side brush firmly. Power the robot back on and start a cleaning cycle to see if the error clears.
• If error persists: Remove the bottom cover (small Phillips screws) to access the side brush motor module. Inspect the wiring harness and connector to the main board. If the motor is burnt, seized, or the plastic gearbox is melted, replace the side brush motor module with a compatible Dreame part.