P1

Intake Air Sensor Abnormal

Mitsubishi Electric · R410A Systems

What does P1 mean?

The intake air sensor (room temperature sensor) on the indoor unit is abnormal, indicating an open circuit, short circuit, or incorrect resistance. This impacts the system's ability to accurately sense room temperature and control operation.

Repair Steps

  1. 1

    Measure the resistance of the intake air sensor at its leads — compare to a resistance-temperature chart if available.

  2. 2

    Inspect the sensor's wiring and connector on the indoor unit PCB for damage, corrosion, or secure seating.

  3. 3

    Verify the sensor is not physically damaged or dislodged from its intended position.

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Verified technical data. Last updated: March 2026
Source: Mitsubishi Electric R410A Systems