Vacuum shows E09 and the LED battery indicator flashes abnormally; unit may shut down randomly even with apparent charge.

Safety: Do not open the battery casing. Handle the pack carefully and avoid dropping it.

• 1. Reseat battery: Remove the battery and reinstall it firmly until it clicks. Poor contact can cause communication errors.
• 2. Clean contacts: Gently clean all battery and vacuum contacts with a dry cloth. Ensure no moisture or corrosion is present.
• 3. Check for swelling or damage: Inspect the battery pack for bulging, cracks, or signs of overheating. If present, discontinue use immediately and replace the pack.
• 4. Firmware check (if applicable): Some advanced Siemens models may require firmware updates for compatibility with newer battery packs. Consult Siemens support or the user manual.
• 5. Replace battery pack: If E09 persists with a fully charged pack and clean contacts, the BMS inside the battery is likely defective. Replace with a genuine Siemens battery.

Do not attempt to reset or bypass the BMS; it is a critical safety component.