Microwave shows E05 and stops heating; fan may continue briefly before shutting off.

Safety first: Unplug the microwave before opening the cabinet. Avoid contact with high-voltage components.

Steps:

• 1. Allow cooling: If the microwave has been used heavily, let it cool for 30 minutes, then try again. Sometimes an overheated sensor can temporarily misread.
• 2. Power reset: Unplug for 5 minutes, then reconnect and test. If E05 returns immediately, the sensor circuit is likely faulty.
• 3. Locate the cavity sensor: Remove the outer cabinet. The cavity temperature sensor (thermistor) is usually clipped to the top or side of the oven cavity or waveguide, with two small wires leading to the control board.
• 4. Inspect connections: Check that the thermistor plug is firmly seated on the control board and that the wires are not pinched or burned.
• 5. Test the thermistor: With the unit unplugged, disconnect the thermistor and measure its resistance at room temperature. Compare to MasterChef specifications (commonly 100kΩ or similar at 25°C). Replace if open, shorted, or far out of range.

Note: If the thermistor tests good and wiring is intact, the control board sensor circuit may be defective and require replacement.