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ED

ED - Serial communication fault between Ecodan main and inverter boards

Mitsubishi Electric · Air Conditioning

What does ED mean?

This fault indicates a serial communication error between the Ecodan's main board and its inverter board, often due to loose cable connections.

Common Causes

  • Loose CN2 or CN5 cable
  • Faulty communication between boards
  • Damaged cable

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the connection of the CN2 cable.

  2. 2

    Ensure the CN5 cable is securely connected.

  3. 3

    Inspect the cables for any signs of damage.

  4. 4

    Restart the Ecodan unit after checking connections.

Browse all codes in this manual (177)
Verified technical data. Last updated: April 2026

Related Faults

0.5-second ON / 0.5-second OFF blinkUpper lamp blinks 0.5-second ON/OFF - Miswiring or serial signal error0.5s blink with beepLeft OPERATION INDICATOR lamp blinks every 0.5 seconds with a beep — Indoor or outdoor unit abnormality00Normal operation - No error codes
Source: Mitsubishi Electric Air Conditioning
Open Manual (Page 35)Search more codes in this manual