Microwave stops shortly after starting and displays E1 on the control panel.

Safety warning: Unplug the microwave before opening the cabinet. Avoid contact with the high-voltage section (transformer, capacitor, magnetron) unless you are trained and have discharged the capacitor.

• Step 1 – Power reset: Disconnect power for 5–10 minutes, then reconnect and test. Sometimes E1 can be triggered by a transient fault.
• Step 2 – Locate the temperature sensor: On Bomann microwaves with grill or convection, the cavity temperature sensor (NTC) is usually mounted on the top or rear of the cooking cavity, often behind a small metal cover or near the grill element.
• Step 3 – Inspect wiring: With the unit unplugged, remove the outer cabinet. Trace the two-wire harness from the sensor to the control PCB. Check for loose connectors, corrosion, or damaged insulation. Reseat the connector firmly.
• Step 4 – Test the sensor: Disconnect the sensor from the harness. Use a multimeter set to resistance (kΩ). At room temperature, an NTC sensor typically reads between 5–100 kΩ (exact value depends on model). If it reads open (OL) or near 0 Ω, the sensor is defective and must be replaced.
• Step 5 – Replace if needed: Remove the mounting screw or clip holding the sensor, fit the new sensor, and reconnect the harness. Ensure it has good thermal contact with the cavity wall.
• Step 6 – Control board check: If a known-good sensor still results in E1, the control PCB’s sensor circuit may be faulty. This repair is best handled by an authorized Bomann service center.