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F4

F4 - 49C connector open

Mitsubishi Heavy Industries · R410A Systems

What does F4 mean?

An open or disconnected 49C connector has been detected in the outdoor unit. This suggests a problem with a specific electrical connection.

Common Causes

  • Loose or disconnected 49C connector.
  • Damaged wiring.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Turn off the main power supply to the air conditioning system.

  2. 2

    Wait for at least 30 seconds before turning the power back on.

  3. 3

    If the error reappears, it indicates an internal wiring problem that requires professional attention.

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

Related Faults

E0E0 - Transmitting/receiving signal errorE12E12 - Auto address setting error or unit addressed at factory settingE14E14 (Flashes 3 times) - Master/slave system control wiring error
Source: Mitsubishi Heavy Industries R410A Systems
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