Compressor Discharge Temperature Sensor (THOD) Defective

What does E39 mean?

The compressor discharge temperature sensor (THOD) is defective (resistance is open circuit) or has a poor connection to the outdoor unit PCB. This prevents accurate monitoring and protection of compressor discharge temperature, risking compressor damage.

1. 1

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

2. 2

   Inspect the THOD sensor's connector on the outdoor unit PCB — verify it is securely seated and free from corrosion.

3. 3

   Check for damage to the sensor wiring between the sensor and the PCB using a multimeter for continuity.