Freezer displays E1 and temperature is higher than setpoint; food feels soft or partially thawed.

Safety first: Unplug the Zanussi freezer from the mains before removing any panels. Do not work on live circuits.

• Power reset: Disconnect power for 5–10 minutes, then reconnect. If E1 clears temporarily and returns, continue with checks.
• Locate the freezer NTC: On most Zanussi upright freezers, the freezer temperature sensor is clipped to the evaporator or mounted behind the inner liner (often behind a small cover at the rear of the freezer compartment).
• Inspect wiring and connectors: Remove the rear internal panel (if accessible) and visually check the sensor wiring for cuts, pinches, or corrosion. Ensure the plug is firmly seated on the sensor and on the main control board (usually behind the external rear panel or in the top control housing).
• Test the sensor: With a multimeter set to resistance (ohms), measure the NTC at freezer temperature (around -18°C if possible). Compare to Zanussi service values (typically 4–15 kΩ depending on temperature). An open circuit (infinite resistance) or 0 Ω indicates a failed sensor.
• Replace if faulty: If readings are out of spec, replace the freezer temperature sensor (NTC). Route the new sensor along the original path and secure it away from moving parts or sharp edges.
• Check the control board: If the sensor and wiring are good but E1 persists, the main control PCB may have a defective sensor input. Inspect for burnt components or corrosion; replacement of the PCB is usually required.

If you are not comfortable testing live circuits or accessing the control board, contact a qualified Zanussi technician.