F4

49C Connector Open

Mitsubishi Electric · R410A Systems

What does F4 mean?

The 49C connector on the outdoor unit's PCB is detected as open or disconnected. This indicates a break in a circuit, likely related to a current transformer or a thermal protector within the outdoor unit.

Repair Steps

  1. 1

    Inspect the 49C connector on the outdoor unit PCB — verify it is securely seated and free from corrosion.

  2. 2

    Check the continuity of the wiring connected to the 49C connector using a multimeter.

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Verified technical data. Last updated: March 2026
Source: Mitsubishi Electric R410A Systems