E2 error code displayed and the lower zone temperature is inaccurate or not cooling correctly.

Safety: Unplug the cooler before removing interior or rear panels. Use insulated tools.

• Identify lower-zone sensor: In dual-zone Aobosi wine coolers, the lower-zone sensor is usually mounted on the rear wall or near the evaporator cover of the lower compartment.
• Visual inspection: Remove any shelves and the lower back panel (if present). Look for a small probe or sensor clipped to the evaporator fins or mounted behind a plastic cover. Check for corrosion, ice buildup, or physical damage.
• Defrost if iced over: If the sensor is encased in ice, leave the unit unplugged with the door open for several hours until all ice melts. Do not chip ice with sharp tools.
• Check wiring: Trace the sensor cable to where it exits the cabinet and connects to the main PCB. Ensure the connector is fully seated and the wires are not pinched or broken.
• Measure resistance: Disconnect the sensor from the board and measure its resistance at room temperature. Compare to the expected NTC curve. Replace the sensor if readings are out of specification.
• Install replacement: Fit a new lower-zone NTC sensor, ensuring good contact with the evaporator or mounting surface. Secure the wire away from the fan and moving parts.
• Final check: Reassemble, restore power, and verify that the E2 code clears and the lower zone reaches and maintains the set temperature.