Mitsubishi Electric Mini-Split Code EB
Soft lockout
Miswiring of the indoor/outdoor unit connecting wire - converse (reversed) wiring or disconnection. The outdoor board could not set the indoor unit number within 4 minutes of power-on.
Manual wording: “Miswiring of indoor/outdoor unit connecting wire (converse wiring or disconnection)”
Documented for: A-Control outdoor units (PUZ, MUZ, MXZ)
Likely causes, most common first
- Contact failure or miswiring of the indoor/outdoor unit connecting wire
- Connecting wire diameter or length is outside the specified capacity
- Defective transmitting/receiving circuit on the outdoor or indoor controller board
- Two or more outdoor units set to refrigerant address 0 in a group control system
- Noise on the power supply or connecting wire
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
Reversed or disconnected connecting wires between indoor and outdoor units must be corrected by 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