Refrigerator display shows E1 and interior temperature is too warm.

Safety first: Unplug the refrigerator from the mains before removing panels or handling wiring. Do not work on live circuits.

Step-by-step checks:

• Power cycle: Disconnect power for 5 minutes, then reconnect. If E1 returns after a few minutes, continue.
• Locate the fridge NTC sensor: On most Neff bottom-freezer models, the fresh food sensor is behind a small plastic cover on the rear interior wall or near the air outlet from the freezer.
• Inspect the sensor and wiring: Remove the cover, visually check the sensor body and wires for damage, cuts, or corrosion at the connector.
• Test the sensor (if you have a multimeter): Disconnect the sensor and measure resistance at room temperature. Typical NTC values are around 5–10 kΩ at 25°C (consult the exact spec for your model). If the reading is open (infinite) or shorted (near 0 Ω), the sensor is faulty.
• Check harness continuity: With the fridge unplugged, check continuity from the sensor connector to the main control board connector. Repair or replace damaged wiring.
• Replace the sensor: If the sensor is out of spec, install a genuine Neff fridge compartment NTC sensor, secure it in the original position, and refit the cover.
• Control board check: If a known-good sensor and wiring are present but E1 persists, the main control board temperature input may be defective. This typically requires board replacement and is best done by a qualified technician.