Vacuum does not respond to trigger or power button; display (if equipped) shows E4 or four red flashes; unit previously exposed to liquid or very humid environment.

Safety first: Immediately stop using the vacuum if it has come into contact with water or other liquids. Remove the battery pack and do not attempt to charge it. Risk of electric shock or fire exists if used while wet.

• Dry the exterior: Wipe all external surfaces with a dry cloth. Do not use heat guns or hair dryers on high heat, as this can warp plastic and damage electronics.
• Air-dry the unit: With the battery removed, place the vacuum in a warm, dry, well-ventilated area for at least 24–48 hours. Position it so that any internal moisture can drain away from the handle and electronics.
• Inspect contacts: After drying, check the battery terminals and charging contacts for corrosion (white or green deposits). Light corrosion can be gently removed with a pencil eraser or a cotton swab with isopropyl alcohol. Severe corrosion indicates the need for part replacement.
• Do not open sealed electronics unless qualified: If the error persists after thorough drying, the main control PCB or switch assembly may be damaged. These components should be replaced rather than repaired at home.
• Replace damaged parts: If you see visible corrosion on the control board or wiring harness, discontinue use and have the unit serviced. Replace the battery pack if it was directly exposed to liquid.