Robot vacuum stops and shows E3; may say 'Side brush error' or 'Side brush blocked' in the Philips app.

Safety first: Turn the robot OFF and flip it over on a soft surface to avoid scratching the top cover.

• Remove the side brush: Pull the side brush straight off its shaft (some models use a small screw; remove it first).
• Clean the hub: Remove hair and fibers wrapped around the base of the side brush and the motor shaft. Use tweezers if necessary.
• Inspect for damage: Check if the side brush arms are bent or deformed. Replace the side brush if the plastic is warped or cracked.
• Check motor rotation: Gently rotate the exposed side brush shaft with your fingers. It should turn smoothly with slight resistance from the gearbox. If it is seized or very rough, the motor/gearbox may be damaged.
• Reinstall and test: Refit or replace the side brush, secure any screw, and start a cleaning cycle. Observe whether the side brush spins normally.
• Persistent E3: If the error returns immediately, the side brush motor or its driver on the main PCB may be defective. Replacement of the side brush motor module is recommended; if that does not resolve it, the main board may need service.