Freezer displays E1 and temperature rises above set point, compressor runs intermittently or not at all.

Safety first: Unplug the freezer from the mains before removing panels or handling wiring. Use insulated tools and avoid working on live circuits.

• 1. Power reset: Disconnect power for 5–10 minutes, then reconnect. If E1 clears temporarily and returns, continue with checks.
• 2. Locate the freezer NTC sensor: On most SMEG freezers, the cabinet temperature sensor is clipped behind an interior liner cover or in a small plastic housing on the rear wall of the freezer compartment. Remove the cover carefully.
• 3. Inspect wiring and connector: Check the sensor leads for cuts, pinches, or signs of moisture ingress. Ensure the connector at the sensor and at the main PCB (usually behind the rear lower service panel or top control housing) is fully seated and corrosion-free.
• 4. Test the sensor: With the appliance unplugged, disconnect the NTC and measure resistance with a multimeter. At around -18°C, many SMEG NTCs read in the 20–40 kΩ range (check your model’s service data if available). A reading of 0 Ω (short) or OL (open) indicates a bad sensor.
• 5. Replace if faulty: If resistance is out of spec or unstable when gently warmed between your fingers, replace the NTC sensor with the correct SMEG part. Route the new sensor wiring along the original path and secure it away from moving parts or sharp edges.
• 6. Reassemble and test: Refit covers, restore power, and monitor the display. Confirm that E1 does not reappear and that the freezer reaches and maintains the set temperature.

When to call a technician: If the sensor tests good but E1 persists, the main control board may have a failed sensor input circuit and should be diagnosed and replaced by a qualified technician.