Display shows E2 and the unit may overcool or not cool; temperature reading is erratic or fixed.

Safety first: Disconnect the appliance from mains before removing rear or internal panels.

Steps to address E2:

• Defrost the unit: If there is heavy ice on the back wall, switch off the cooler and leave the door open for several hours or use a fan to speed up defrosting. Do not use sharp tools to remove ice.
• Access the evaporator area: Remove internal rear panel inside the wine compartment (usually held by screws). Behind it you will find the evaporator coil, fan, and sensor.
• Inspect the evaporator NTC: Look for a small probe clipped or taped to the evaporator tubing. Ensure it is firmly attached and not dangling or broken.
• Check wiring: Follow the sensor wires to the harness. Look for chafing, cuts, or brittle insulation caused by ice. Reseat the connector.
• Test the sensor: With the unit unplugged, disconnect the sensor and measure resistance with a multimeter. Compare to the cabinet sensor if identical type; a reading of OL or 0 Ω indicates failure.
• Replace the evaporator sensor: If faulty, install a new evaporator temperature sensor (NTC) compatible with Siemens wine coolers. Clip or tape it securely to the same coil location to ensure proper temperature feedback.
• Reassemble and test: Refit the rear panel, restore power, and monitor if E2 clears and cooling stabilizes.

If E2 persists with a known-good sensor and wiring, the main control board may require replacement by a professional.