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HA

HA - Malfunction of outdoor air thermistor

Daikin · Air Conditioning

What does HA mean?

The temperature sensor measuring the outdoor air temperature is malfunctioning.

Common Causes

  • Faulty outdoor air thermistor
  • Damaged wiring
  • Sensor obstruction

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Ensure the outdoor air thermistor is clean and unobstructed.

  2. 2

    Power cycle the unit by turning off the breaker for 60 seconds.

  3. 3

    A service technician should inspect and replace the sensor if needed.

Browse all codes in this manual (79)
Verified technical data. Last updated: April 2026

Related Faults

A0A0 - External protection activeA1A1 - Indoor PCB failureA2A2 - Malfunction of freezing protection
Source: Daikin Air Conditioning
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