Robot reports F3 and stops; may indicate a problem with the brush bar or floor tool.

Safety first: Switch the robot OFF and turn it upside down on a soft surface. Never work on the brush bar while the robot is powered.

• Remove the brush bar: Release the end cap or locking tabs on the cleaner head and pull out the brush bar.
• Clear tangles: Use scissors to carefully cut away hair, thread, and fibers from the bristles and end caps. Avoid cutting the bristles themselves.
• Check end bearings: Spin each end of the brush bar with your fingers. It should rotate freely. If it feels gritty, seized, or melted, the brush bar should be replaced.
• Inspect the cleaner head cavity: Look for coins, toys, or debris lodged near the brush bar motor drive. Remove anything obstructing rotation.
• Reassemble and test: Refit the brush bar and end cap securely. Start a short clean on a hard floor and watch the brush bar. If F3 reappears, the brush bar motor or wiring may be faulty.

Persistent F3 after cleaning usually indicates the cleaner head assembly or brush bar motor needs replacement.