Freezer shows F1; temperature display may flash; unit may run continuously or shut down intermittently.

Safety first: Unplug the freezer before accessing internal panels or wiring.

Diagnostic steps:

• Locate the freezer sensor: In Liebherr freezers, the NTC sensor is usually behind an interior wall cover or in a small plastic housing on the rear or side wall of the freezer compartment.
• Visual inspection: Check for damage to the sensor housing, ice build-up around it, or signs of moisture ingress. Gently remove any heavy ice with a plastic scraper; do not use sharp tools.
• Check connections: Trace the sensor cable to where it exits the liner and towards the top or rear electronics compartment. Ensure the plug is firmly seated on the control board and not corroded.
• Resistance check (for advanced DIYers): With the sensor unplugged and the freezer at room temperature, measure resistance with a multimeter. A typical Liebherr NTC will read in the 4–20 kΩ range at room temperature. An open circuit or 0 Ω indicates a failed sensor.

Remedy: If the sensor is open/shorted or physically damaged, replace the freezer compartment NTC sensor with a Liebherr-compatible part. Route the new sensor cable along the original path and ensure all grommets are sealed to prevent moisture ingress.