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E38

E38 - Outside air temperature sensor (ThoA) defective or poor connection

MHI · R410A Systems

What does E38 mean?

This error means the outside air temperature sensor (ThoA) is defective (open circuit resistance) or has a poor connection to the outdoor unit PCB.

Common Causes

  • Faulty ThoA sensor.
  • Loose or corroded connection of the ThoA sensor on the outdoor unit PCB.
  • Damaged wiring to the ThoA sensor.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Turn off the main power to the outdoor unit at the circuit breaker.

  2. 2

    Have a qualified technician inspect the ThoA sensor and its wiring connections on the outdoor unit PCB.

  3. 3

    Ensure all connections are secure and free from corrosion.

  4. 4

    The technician will test the sensor's resistance and replace it if it's faulty.

Browse all codes in this manual (58)
Verified technical data. Last updated: April 2026

Related Faults

E0E0 - Transmitting/receiving signal error in indoor unitE12E12 - Address setting conflict or auto address failureE14E14 - 3 flashes - Master/slave system wiring or SW settings error
Source: MHI R410A Systems
Open Manual (Page 4)Search more codes in this manual