F18
Liebherr CAN / Data Bus Communication Fault

Freezer shows F18; may indicate internal communication error between multiple control boards (e.g., UI and main PCB).

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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

Loose data cable between boards, Damaged communication harness, Faulty control PCB transceiver

How to Fix / Troubleshooting

Safety first: Unplug the freezer before accessing electronics.

Steps:

  • Locate all boards: Identify the main control board (usually top or rear) and any secondary boards (UI, power module).
  • Check harnesses: Reseat all multi-wire connectors between boards. Look for bent pins or corrosion.
  • Inspect for damage: Examine cables for pinch points, especially around hinges and tight passages.

Remedy: Replace any damaged harness. If F18 remains with good wiring, one of the control boards is likely defective and should be replaced as a matched part for the model.

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Repair Difficulty

Professional Required 5/5

Required Part

Main Wiring Harness between Control Boards
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