Indoor unit stops, E2 displayed, fan may run briefly then stop

Safety first: Isolate power at the breaker before opening the indoor unit.

Steps:

• Access the thermistor: Remove the front panel and air filters. The room temperature thermistor is usually clipped near the indoor coil inlet or in the return air path, connected by two small wires to the PCB.
• Check connection: Ensure the thermistor plug is firmly seated on the indoor PCB. Reseat the connector.
• Inspect the sensor: Look for broken wires, damaged insulation, or a sensor that has fallen out of its clip. Reclip it securely in the airflow path.
• Resistance check: With power OFF, disconnect the thermistor and measure its resistance with a multimeter. Compare to Mitsubishi Electric’s temperature–resistance chart (e.g., around 10–20 kΩ at room temperature depending on model). Infinite or near-zero resistance indicates a bad sensor.
• Replace thermistor: If readings are out of spec, replace the room temperature thermistor with the correct Mitsubishi Electric part number for your model.
• PCB check: If a known-good thermistor still triggers E2, the indoor PCB sensor circuit may be defective and require replacement.