Refrigerator compartment not cooling properly, temperature too high, alarm may sound and E01 appears on display.

Safety first: Disconnect the Gaggenau refrigerator from mains power by unplugging it or switching off the circuit breaker before removing panels or handling wiring.

Step-by-step checks:

• 1. Power reset: Turn the unit off at the breaker or unplug for 5 minutes, then restore power. If E01 returns after a few minutes of operation, continue with diagnostics.
• 2. Verify cooling and airflow: Ensure the refrigerator compartment vents are not blocked by food items and that the interior fan is running when the door is closed (press the door switch to test). Poor airflow can cause high temperature but will not usually clear E01 if the sensor is faulty.
• 3. Access the refrigerator NTC sensor: The refrigerator temperature sensor is typically located behind a small plastic cover on the rear interior wall or in the air duct. Remove shelves as needed, then gently pry off the cover.
• 4. Inspect wiring and connector: Check the sensor wiring harness for damage, pinched sections, or corrosion at the connector. Reseat the connector firmly into the harness. If any wire is broken, the harness must be repaired or replaced.
• 5. Test the sensor (if you have a multimeter): With power still disconnected, unplug the sensor from the harness and measure its resistance. At around 25°C (77°F), most Gaggenau NTC sensors read roughly 4–6 kΩ (exact value varies by model). An open circuit (infinite resistance) or a dead short (near 0 Ω) indicates a failed sensor.
• 6. Replace the sensor if defective: If readings are out of range or E01 persists, replace the refrigerator compartment NTC sensor with the correct Gaggenau/Bosch-compatible part for your model. Route the new sensor wiring exactly as the original to avoid pinching.
• 7. Consider control board: If a known-good sensor and wiring are present but E01 still appears, the main control module (often located in the top or rear electronics compartment) may have a failed input circuit and should be diagnosed and replaced by a qualified technician.

When to call a professional: If you are not comfortable testing resistance or accessing internal wiring, or if replacing the sensor does not clear the error, contact an authorized Gaggenau service technician.