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T173

T173 — Loss of communication with the Energy Management Module

Carrier · Energy Recovery Ventilators

What does T173 mean?

Communication has been lost with the Energy Management Module. The unit will not take any action related to it.

Common Causes

  • MBB (Main Board) software failure
  • Communication wiring issue

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the communication wiring between the unit and the Energy Management Module.

  2. 2

    Restart the MBB or unit.

  3. 3

    If the problem persists, reload the software or replace the MBB.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

1 Fault CodeFault Code 1 — OVERCURRENT10 Fault CodeFault Code 10 — PANEL LOSS11 Fault Code11 Fault Code — ID RUN FAIL
Source: Carrier Energy Recovery Ventilators
Open Manual (Page 47)Search more codes in this manual