F4
TCL Low Voltage / Power Supply Instability

Vacuum shows F4 and the LED work light or display flickers; unit may shut off randomly.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Aged battery with high internal resistance, Loose battery terminals, Corroded battery contacts on vacuum body, Faulty DC-DC converter on main PCB

How to Fix / Troubleshooting

Safety first: Remove the battery and disconnect the charger before inspecting contacts.

  • 1. Inspect battery contacts: Look at the metal terminals on the battery and inside the battery bay. Clean gently with a dry cloth.
  • 2. Reseat battery: Insert the battery firmly until it clicks. Check for any wobble or looseness.
  • 3. Test with full charge: Fully charge the battery, then run the vacuum. If F4 appears quickly, the battery may be failing.
  • 4. Try another battery (if available): If your TCL model supports removable batteries and you have a spare, test with the second pack.

Next step: If F4 persists with a known‑good battery, the internal power regulation circuitry on the main PCB is likely defective and should be replaced by a service technician.

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Repair Difficulty

Medium 3/5

Required Part

Main Lithium-Ion Battery Pack
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