Vacuum shuts down after a few seconds of operation; error E3 or triple-blink LED pattern

Safety first: Remove the battery pack and allow the tool to cool for at least 20 minutes before inspection.

• Clean cooling vents: Inspect all air intake and exhaust vents on the vacuum housing. Use a soft brush and compressed air to remove dust buildup. Do not insert metal objects into vents.
• Inspect and replace filters: Remove the main filter and any pre-filters. If they are heavily loaded with fine dust, replace them with Hilti-approved filters. Operating with clogged filters causes overheating.
• Check for heavy-duty misuse: If the vacuum is being used continuously in fine dust (e.g., concrete grinding), use pulse-cleaning (if equipped) more frequently and allow rest periods.
• Test after cooling: Reinstall a clean filter, insert a fully charged battery, and run the vacuum with no hose attached. If it runs longer without error, the issue was airflow-related.
• If E3 returns quickly: The motor’s thermal sensor or the motor windings may be damaged. Continued use can cause permanent failure; have the motor assembly and sensor checked and replaced by a Hilti service technician.