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A169

A169 - Expansion Valve Control Board Comm Failure

Carrier · Air Conditioning

What does A169 mean?

Communication has failed with the Expansion Valve Control Board. The Humidi-MiZer control is disabled.

Common Causes

  • Incorrect wiring
  • Loss of power to the control board
  • Faulty control board

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Ensure the Humidi-MiZer control board has power.

  2. 2

    Inspect all wiring connections to the control board.

  3. 3

    A technician needs to diagnose the communication issue and test the board.

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

Related Faults

A051A051 - Compressor 1 Stuck On FailureA052A052 - Compressor 2 Stuck On FailureA055A055 - Compressor 1 Stuck On Failure (Circuit B)
Source: Carrier Air Conditioning
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