Outside Air Temperature Sensor (ThoA) Defective / Poor Connection

What does E38 mean?

The outside air temperature sensor (ThoA) is defective (open circuit resistance) or has a poor connection on the outdoor unit PCB. This compromises the system's ability to accurately sense ambient conditions and adjust operation.

• Outside air temperature sensor (ThoA, e.g., P16) is defective.
• Poor electrical connection to the ThoA sensor.
• Sensor reading is incorrect or intermittent.
• Wiring to the sensor is compromised.
• Extreme ambient temperatures affecting sensor performance.

Click steps to track your progress.

1. 1

   Measure the resistance of the outside air temperature sensor (ThoA) and compare to the specified temperature-resistance chart.

2. 2

   Inspect the ThoA sensor connector on the outdoor unit PCB for secure connection and check for wire damage.