E15 error; freezer may not cool correctly and may show inconsistent temperature readings.

Safety first: Disconnect power before accessing sensors or the control board.

Identify all sensors:

• Cabinet NTC (interior liner), evaporator NTC, ambient NTC, and sometimes a separate defrost NTC.
• Use the wiring diagram to locate each sensor and its connector on the main PCB.

Systematic testing:

• Disconnect each sensor one at a time and measure resistance at a known temperature (e.g., room temperature).
• Compare readings between similar NTC types; large deviations suggest a faulty sensor.
• Inspect each sensor's mounting to ensure proper contact with the surface it is meant to measure.

Corrective actions:

• Reattach sensors: If a sensor has come loose from the evaporator or liner, reattach using the original clip or thermal tape.
• Replace out-of-range sensors: Install Blomberg-compatible NTC sensors for any that show open, short, or clearly incorrect resistance.
• Repair harness: Fix any intermittent or damaged wires and connectors.
• If all sensors and wiring are verified good but E15 persists, the main PCB's sensor reading circuitry may be defective and require replacement.

Test: Restore power and monitor temperature readings and operation over 24 hours to confirm stability and absence of E15.