The vacuum will not start and shows E4; this sometimes occurs after battery removal or a drop.

Safety first: Remove the battery and disconnect the charger. Do not short-circuit the battery terminals.

• Reseat battery: Remove the battery pack fully and reinstall it firmly until it clicks into place. Ensure there is no play in the connection.
• Inspect contacts: Check the metal power and data contacts on the battery and inside the handle/battery bay for bent pins, corrosion, or contamination. Clean them gently with a dry cloth or cotton swab and isopropyl alcohol.
• Check battery type: Confirm you are using the correct original Logik battery model specified for your cordless vacuum. Third-party or mismatched packs can trigger E4.
• Test with another battery: If possible, test with a known-good, compatible Logik battery. If the error disappears, your original pack’s BMS is faulty, and the pack should be replaced.
• Inspect handle connector: If E4 persists with multiple batteries, the battery connector or control PCB in the handle may be damaged and require replacement by a technician.