Oven shows E15; internal temperature reading is obviously wrong (e.g., shows very high or very low when cold).

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

• Verify with thermometer: Use an oven-safe thermometer to compare actual cavity temperature with the displayed temperature during a short bake cycle.
• Inspect sensor mounting: Ensure the sensor probe is firmly mounted and not loose or pulled away from the cavity wall.
• Test sensor resistance: Remove the sensor and measure resistance at room temperature and at a known elevated temperature (e.g., in warm water, if removable). Compare to Blomberg specifications.
• Check harness: Inspect the wiring from the sensor to the PCB for damage or corrosion at connectors.
• Replace components: Replace an out-of-spec temperature sensor. If the sensor and wiring are correct but readings remain inaccurate, the main control board may require replacement or recalibration by a technician.