Vacuum runs but then shuts off with E9 when using high-power mode

Safety first: Remove the battery pack before inspection.

• Reduce load: Remove hose and accessories and run the vacuum in low-power mode. If it runs without error, gradually increase power and reattach accessories to identify when the fault occurs.
• Check for blockages: Ensure hose, tubes, and nozzles are clear. A partially blocked nozzle can cause high current draw.
• Use a high-capacity battery: For high-power operation, use a higher-capacity Hilti battery (e.g., B 22‑85 instead of B 22‑55) to ensure adequate current supply.
• Monitor for burning smell or heat: If the housing becomes very hot or you smell burning, stop use immediately. This indicates motor or PCB damage.
• Service required: Persistent E9, especially with clear airflow and correct battery, indicates a failing motor or power stage on the PCB. Have these components tested and replaced professionally.