Mitsubishi Electric E6 Error Code: Indoor/outdoor unit communication error
Updated October 2026 · Sourced from Mitsubishi Electric documentation
🧭 Check a few things first
The indoor unit reports a communication error with the outdoor unit. The manual lists E6 and E7 together under 3 flashes.
Is it safe to keep running? Check the steps below first. If E6 returns, the wiring between the indoor and outdoor units or a control board needs a technician.
E6 at a glance
| Code / how it shows | Meaning | Applies to |
|---|---|---|
| E6 Also: E7 Wireless remote: the OPERATION INDICATOR lamp flashes 3 times in a self-check; wired remote shows the code | Indoor/outdoor unit communication error | PLA-RP35/50/60/71/100/125/140BA ceiling cassette indoor units (Mr. Slim, OCH416 service manual) |
Check this first
Only steps a homeowner can do safely. Do not open electrical panels or the burner area.
- Turn the unit off, switch the breaker off for a minute, then back on.
- Check that the outdoor unit has power and its disconnect switch is on.
🛑 Stop and call a licensed pro if
- If E6 returns, the wiring between the indoor and outdoor units or a control board needs a technician.
- Any code pointing to refrigerant, the compressor, high pressure or the outdoor unit board. Refrigerant work legally needs a certified technician.
- Burning smell, sparks, or a breaker that trips again after a reset.
- Water leaking from the indoor unit that does not stop after the drain is clear.
Safe first steps for any Mitsubishi Electric code
- Write down the exact code and how it shows (remote display or number of lamp blinks). Similar codes mean different things on different series.
- Turn the system off at the remote, switch off the breaker or disconnect for the unit, wait a few minutes, then turn it back on.
- Clean or replace the indoor unit air filters, and make sure nothing blocks the indoor or outdoor unit.
- Check that the condensate drain line is not blocked or kinked where you can see it.
- Replace the remote controller batteries if the display is dim or the unit does not respond.
Source: Mitsubishi Electric PLA-RP BA Service Manual OCH416 Rev. D, p.22. Codes are series-specific, so your unit's own manual is the final word. Reviewed October 2026.
Shaun Cain · Certified HVAC & Refrigeration Technician · Ask an HVAC technician
Related Mitsubishi Electric codes
P1 : Intake (room) sensor errorP2 : Pipe (liquid) sensor errorP9 : Pipe (condenser/evaporator) sensor errorP4 : Float switch connector openP5 : Drain pump error (water leakage abnormality)PA : Forced compressor stopP6 : Freezing or overheating protection operationEE : Communication error between indoor and outdoor unitsP8 : Pipe temperature errorE4 : Remote controller signal receiving errorFb : Indoor unit control system errorPL : Refrigerant circuit abnormal