Microwave displays E3 and may stop during sensor cooking or not allow sensor modes.

Safety first: Unplug the microwave before accessing internal sensors.

• Clean interior: Thoroughly clean the cavity, especially around any sensor covers or ports. Grease and residue can affect sensor readings.
• Dry the cavity: Leave the door open for several hours to ensure no condensation remains on sensors.
• Inspect sensor wiring: Access the control area and check the harnesses for the cavity thermistor and humidity sensor. Reseat connectors and look for damage.
• Test sensors: Using the service manual, measure sensor resistances at room temperature. Replace any sensor that is out of specification.
• Replace control board if needed: If sensors and wiring are good but E3 persists, the control board's sensor input circuit may be faulty and require replacement.