LG Freezer Error Code UU/UU

The UU/UU error code on an LG freezer indicates a simultaneous over-cooling and weak-cooling condition occurring in both the upper and lower compartments at the same time. This dual-zone failure points to a problem within the refrigerant flow system rather than an isolated section malfunction. When the freezer cannot properly regulate temperature in either zone simultaneously, the control board registers this as a critical cooling imbalance and triggers the UU/UU alert. In many cases, the overload protector (OLP) will also activate as a safety response to the abnormal operating conditions.

The root cause typically involves the switch valve and its associated components. The switch valve controls refrigerant distribution between the upper and lower cooling circuits. If the valve fails to actuate properly, refrigerant flow becomes erratic or blocked, causing simultaneous cooling problems in both zones. A clog in the capillary tube, often caused by contamination or a welding defect at the tube joint, can restrict refrigerant flow to the point where the system cannot achieve proper heat exchange in either compartment. Technicians should check the switch valve terminal connections for loose or corroded contacts before proceeding to more invasive diagnostics.

Diagnosis begins with verifying the switch valve terminal location and confirming that electrical signals are reaching the valve correctly. From there, inspection of the capillary tube for welding clogs is essential, as these restrictions are a known failure point. If the capillary tube is clear, the switch valve itself should be tested for proper mechanical and electrical operation. An OLP activation accompanying the UU/UU code suggests the compressor or a related component may have experienced thermal stress due to the prolonged cooling malfunction, and that condition should be evaluated before restarting the system.