Mitsubishi Electric Mini-Split Code EF
Warning
Non-defined check code. The controller received a check code it does not recognize.
Manual wording: “Non defined check code - This code is displayed when non-defined check code is received.”
Documented for: A-Control indoor and outdoor units
Likely causes, most common first
- Noise has entered the remote controller transmission wire
- Noise has entered the indoor/outdoor unit connecting wire
- Outdoor unit is not an inverter model
What you can safely check yourself
- Turn the system off at the breaker, wait one minute, and turn it back on once
When to call a technician
If EF repeats, the manual calls for replacing the indoor or outdoor controller board, or confirming the outdoor unit is a compatible inverter model. Call a technician.
A Mitsubishi Electric mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- Service Manual No. OCH750 Revised Edition-E - PUZ-HA Outdoor Units (May 2024) (Mitsubishi Electric, PUZ-HA24NHA1, PUZ-HA30NKA, PUZ-HA36NKA, PUZ-HA42NKA1 heat-pump outdoor units) · checked 2026-08-25