Vacuum does not respond to the trigger or power button; E5 appears on the display when the battery is inserted.

Safety first: Remove the battery pack from the vacuum. Do not attempt to cool or heat the battery rapidly (no freezers, ovens, or direct sunlight).

• Normalize temperature: Place the battery in a dry, shaded room at normal room temperature (20–25°C / 68–77°F) for at least 1–2 hours.
• Check for damage: Inspect the battery casing for cracks, swelling, or leakage. If any damage is present, discontinue use and recycle the battery safely.
• Retry operation: Reinsert the battery and power on the vacuum. If E5 clears, the issue was temporary temperature protection.
• Test with another battery: If available, try a second compatible Hitachi battery. If the second battery works normally, the original pack’s temperature sensor is likely faulty.

If E5 persists with multiple batteries, the vacuum’s battery temperature sensing circuit on the main PCB may be defective and requires professional diagnosis.