Freezer shows E2 and struggles to maintain temperature; compressor may run continuously.

Safety: Disconnect the freezer from mains before opening any control covers.

• 1. Confirm the error: Note if E2 appears immediately at power-on or only after some minutes of operation. Persistent immediate E2 often indicates a sensor or wiring issue.
• 2. Locate the ambient/cabinet sensor: On many Siemens freezers, this sensor is behind the control panel fascia or in the upper cabinet area behind a small grille. Remove the control panel cover carefully.
• 3. Inspect wiring and connector: Look for a small two-wire NTC sensor plugged into the main PCB. Check for corrosion, moisture, or loose fit. Unplug and replug the connector several times.
• 4. Visual check of sensor: Ensure the sensor capsule is intact and not broken or exposed. If it is loose from its mounting point, re-secure it so it can sense cabinet temperature correctly.
• 5. Resistance test (optional): With the freezer unplugged, measure resistance of the sensor at room temperature (around 20–25°C). Compare to Siemens specifications if available; a completely open or shorted reading indicates failure.
• 6. Replace sensor if defective: Install a Siemens-compatible ambient NTC sensor, matching connector type. Route the cable away from sharp metal edges and moving hinges.
• 7. Reassemble and test: Refit the control panel, restore power, and allow several minutes for the control to recognize the new sensor. E2 should clear automatically.

Note: If the sensor and wiring are good, the main control board may be faulty and should be evaluated by a qualified technician.