Display shows E12 and the upper zone of a dual-zone wine cooler does not maintain set temperature.

Warning: Unplug the wine cooler before removing any internal panels or trims.

On dual-zone De Dietrich wine coolers, E12 typically refers to a fault in the upper compartment temperature sensor.

• Locate the upper zone sensor: Look for a small probe or plastic cover on the rear or side wall of the upper compartment.
• Inspect the sensor and cable: Check for visible damage, moisture ingress, or loose mounting.
• Measure resistance: Disconnect the sensor and measure its resistance at room temperature. Compare to the lower zone sensor if accessible; they should be similar. An open or very low reading indicates failure.
• Check board connection: Trace the cable to the main PCB and ensure the connector is fully seated.
• Replace sensor: If faulty, install a new upper zone NTC sensor, routing the cable along the original path and sealing any grommets to prevent condensation.
• Test operation: Restore power, clear the error by cycling power, and verify that the upper zone reaches and holds the set temperature.