Microwave beeps and shows E3; cooking does not start.

Safety: Unplug the microwave before removing any covers. Avoid the high-voltage section.

• Step 1 – Clean the cavity and sensor area: Many Bomann models with auto-cook functions use a humidity sensor behind a small grill or window in the top or side of the cavity. Clean the interior thoroughly with a mild detergent and soft cloth, especially around the sensor opening. Dry completely.
• Step 2 – Power reset: After cleaning, leave the door open to dry, then unplug the unit for 5 minutes. Plug back in and test an auto-cook program.
• Step 3 – Access the sensor: If E3 remains, unplug the unit and remove the outer cabinet. Locate the humidity sensor module (often a small PCB near the top of the cavity with a two- or three-wire harness).
• Step 4 – Inspect and reseat connectors: Check the harness from the sensor to the main control board. Reseat connectors and look for corrosion or moisture damage.
• Step 5 – Replace sensor if faulty: If the sensor shows visible damage or if the error persists after cleaning and reseating, replace the humidity sensor module with a Bomann-compatible part.
• Step 6 – Control board diagnosis: If a new sensor does not clear E3, the control PCB may be defective. This typically requires professional replacement and calibration.