Liebherr Error Codes
& Diagnostics

AL02 Freezers The AL02 display message on a Liebherr freezer indicates that cabinet temperature has exceeded the alarm threshold (typically around 10°F / -12°C). The alarm sounds and the AL02 label appears to alert the user that the freezer is no longer holding food at a safe storage temperature. High View details → dF Freezers The dF display message on a Liebherr NoFrost freezer indicates that the defrost cycle has failed to complete normally. The defrost heater is no longer melting frost from the evaporator coil, so ice slowly builds up over days until airflow is blocked and cooling weakens. Medium View details → F12 Freezers The F12 code on a Liebherr standalone freezer indicates that the SuperFrost function is not operating correctly, or that cabinet temperature has overshot during a SuperFrost cycle. SuperFrost rapidly drops freezer temperature to flash-freeze newly-loaded items; F12 means the function cannot complete its cycle as designed. Medium View details → F3 Freezers The F3 code on a Liebherr freezer indicates a fault in the freezer compartment air sensor — the NTC thermistor that measures the actual freezer cabinet temperature. Without a valid reading the control board cannot regulate the freezer cooling cycle correctly, and cabinet temperature drifts away from the set point. High View details → F4 Freezers The F4 code on a Liebherr freezer indicates a fault in the freezer-side evaporator sensor — the NTC thermistor mounted directly on the evaporator coil. Without a valid evaporator reading, the control board cannot run the NoFrost defrost cycle correctly, and frost slowly accumulates on the coil to the point where airflow is restricted. Medium View details → F5 Freezers The F5 code on a Liebherr standalone freezer indicates an electronic control board fault — the main microprocessor has detected an internal error or has stopped responding to its own self-checks. Cooling becomes unpredictable: some F5 modes leave the compressor running on a safe default profile, others stop cooling entirely. High View details → F6 Freezers The F6 code on a Liebherr standalone freezer indicates a communication failure between control components — typically between the main control board and the compressor inverter, or wiring damage in the compressor power circuit. The compressor cannot be commanded reliably and cooling stops or runs intermittently. High View details → F7 Freezers The F7 code on a Liebherr standalone freezer indicates a fault in the ambient (room) air sensor. The board uses ambient temperature to optimize compressor speed compensation for the surrounding environment; without it, the unit runs in a default profile that is less efficient and may struggle in extreme garage or basement temperatures. Low View details → F8 Freezers The F8 code on a Liebherr standalone freezer indicates that the compressor is not starting normally, is running continuously without reaching its target, or is producing abnormal cooling pressure. F8 reflects a problem with the cooling system itself rather than its measurement components. High View details → F9 Freezers The F9 code on a Liebherr standalone freezer indicates that the control board has detected an out-of-range supply voltage condition. The unit may shut down to protect itself, or it may continue running in a degraded mode until the supply stabilizes. Garage and basement installations are particularly prone to F9 because of shared circuits with high-load equipment. High View details →