Vacuum leaves lines of debris behind and does not pick up well from carpets.

Safety first: Turn off the vacuum and remove the battery.

• Inspect brush roll: Remove the brush and check bristle length. If bristles are worn down or uneven, replace the brush roll.
• Clean nozzle: Remove debris from the nozzle opening and side channels.
• Check brush speed: Reinstall the brush and run the vacuum. Observe whether the brush spins strongly. If it slows easily when contacting carpet, the brush motor may be weak.