6801
Moderate
Mitsubishi Electric · Mini-Splits & Ductless Systems
Communication Error (Wired Controller)
Quick Answer
Error code 6801 on your Mitsubishi Electric Mini-Splits & Ductless Systems means: Communication Error (Wired Controller). This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
Likely Causes
How to Fix It
1
Check the controller cable connections at both the controller and the indoor unit terminal block
2
Test the controller cable for continuity on all conductors
3
Verify the cable length does not exceed the maximum specification (typically 500 meters for Mitsubishi controllers)
4
Try connecting a known-good controller to isolate whether the controller or PCB is at fault
5
If wiring checks out and a replacement controller does not resolve the issue, the indoor PCB may need replacement
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
Controller cable
Wired controller (PAR or MAC series)
Indoor PCB
Related Error Codes