e6
Moderate
Mitsubishi Electric · Mini-Splits & Ductless Systems
Indoor/Outdoor Communication Error
Quick Answer
Error code E6 on your Mitsubishi Electric Mini-Splits & Ductless Systems means: Indoor/Outdoor Communication Error. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Communication wire between indoor and outdoor units damaged or disconnected
  2. Loose terminal connections at the indoor or outdoor unit
  3. Indoor or outdoor PCB communication circuit failure
  4. Incorrect wiring sequence at the terminal blocks
How to Fix It
1
Check all wiring connections at the indoor and outdoor unit terminal blocks and tighten as needed
2
Verify the communication wire has continuity between the units using a multimeter
3
Confirm the wiring matches the wiring diagram exactly (polarity matters on communication wires)
4
Inspect the cable for physical damage along its entire run
5
If wiring checks out, a licensed HVAC technician should test the communication circuits on both PCBs
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Interconnecting wire cable
Indoor PCB
Outdoor PCB
Terminal connectors
Related Error Codes
Video Guides
Loading video guides…
Search more on YouTube →