Safety first: Turn off power at the mains before removing the oven from the cabinet.

Access the sensor wiring: Pull the oven slightly out of the cabinet. Remove the rear cover to expose the sensor harness where it passes through the cavity.
Check connector seating: Locate the sensor plug on the main control board and ensure it is fully inserted and locked.
Inspect cable for damage: Look for pinched, melted, or cut insulation where the cable passes through metal panels. Repair with high-temperature wire and proper connectors if damaged.
Measure resistance at the board: With the sensor connected, measure resistance at the board connector pins. If the reading is open or near 0 Ω, disconnect the sensor and test directly at the sensor. This helps determine if the fault is in the sensor or the harness.
Replace faulty sensor: If the sensor is defective, remove the mounting screw inside the cavity, pull out the sensor, and install a new Grundig-compatible NTC probe.

Warning: Do not bypass the sensor; it is a critical safety component preventing overheating.

Oven display shows error shortly after start, fan runs but no heat

Possible Causes