E6
Mitsubishi Electric Outdoor Unit Communication or Power Supply Error

Indoor unit shows E6, outdoor unit does not start, no cooling or heating

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

No power to outdoor unit, Blown outdoor unit fuse, Faulty outdoor control PCB, Loose inter-unit wiring at outdoor terminals

How to Fix / Troubleshooting

Safety first: Turn off all power at the main disconnect before opening the outdoor unit.

Steps:

  • Check outdoor power: Verify the outdoor unit’s breaker or disconnect is ON and not tripped. Reset if necessary.
  • Inspect fuses: Many Mitsubishi Electric outdoor units have internal fuses on the PCB or terminal block. Check and replace blown fuses with the same rating after identifying the cause.
  • Verify wiring: Confirm that the interconnecting cable from the indoor unit is firmly connected to the outdoor terminal block and that there are no loose or burnt terminals.
  • PCB inspection: Look for burnt components, swollen capacitors, or damaged tracks on the outdoor PCB. If present, the board must be replaced.
  • Technician diagnostics: If power and wiring are correct but E6 persists, a technician should check DC bus voltage, inverter module status, and communication signals.
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Repair Difficulty

Hard 4/5

Required Part

Outdoor Control PCB
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