F9 is displayed; the vacuum may show abnormal runtime estimates or shut off unexpectedly despite showing a charge.

Safety: Use only in a dry environment and monitor for overheating.

• Recalibrate battery (if supported): Fully charge the battery, then run the vacuum continuously in normal mode until it shuts off. Fully recharge without interruption. Repeat once more.
• Observe runtime: If runtime remains very short, the battery cells are likely worn out.
• Replace battery: Install a new original Dreame battery pack if calibration does not improve performance.

If a new battery still triggers F9, the main PCB’s battery sensing circuit may be faulty and needs professional repair.