Error Code: EC 52 – ODU Coil Temperature Sensor (T3) Error

Error Code: EC 52 – Outdoor Coil Temperature Sensor (T3) Error
Applies to LETO and AURA Series

What this means:
The outdoor unit’s coil temperature sensor (T3) is either shorted, disconnected, or reporting abnormal values. This sensor helps control the outdoor unit’s operation, and the system will shut down if the readings are out of range.

Try this first (easy fix):

1. Turn off power to your mini split completely.

2. Wait 2 full minutes.

3. Turn the power back on and check if the error is still showing.

• If the error is gone — your system is working again.

• If the error remains — continue with the steps below.

Next steps (for technicians):

• Check the wiring connection between the temperature sensor and the outdoor PCB.

• Make sure it’s properly connected and not damaged.

• Measure the sensor’s resistance:

  • If the reading is out of range, replace the sensor.

  • If the sensor is good, but the issue continues, the outdoor PCB may be faulty.

What you might need:

• Outdoor coil temperature sensor (T3)

• Outdoor PCB

• Connection wires (if loose or corroded)

Helpful tip:
Some models use a combination sensor where T3, T4, and TP are the same component. Always confirm the sensor type for your unit before replacing it. When the voltage is below 0.06V or above 4.94V, the system triggers this error code.

Click here to view the detailed guide. TS05-ODU