Mitsubishi Electric Mini-Split Code UP
Soft lockout
Compressor overcurrent interruption. Overcurrent on the DC bus or compressor was detected after the compressor had been running for 30 seconds or more.
Manual wording: “Compressor overcurrent interruption - Abnormal if overcurrent DC bus or compressor is detected after compressor starts operating for 30 seconds.”
Documented for: A-Control outdoor units (PUZ, MUZ, MXZ)
Likely causes, most common first
- Stop valve is closed
- Decrease of power supply voltage
- Looseness, disconnection or reversed connection of the compressor wiring
- Defective fan on the indoor or outdoor units
- Short cycle on the indoor or outdoor units
- Defective indoor or outdoor coil
- Defective compressor
- Defective outdoor power circuit board
- DIP switch setting difference on the outdoor controller board
What you can safely check yourself
- Remove and clean or replace the indoor air filters
- Check that the outdoor unit is clear of snow, ice, leaves and stored items
- Clear anything blocking the indoor unit inlet or outlet
- Turn the system off at the breaker, wait one minute, and turn it back on once
When to call a technician
If airflow is clear and UP returns, the compressor, its wiring, the stop valve or the power supply is at fault. 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