Mitsubishi Electric Mini-Split: 6 Flashes
Code 6 blinks: Outdoor thermistor error
Soft lockoutShown as: Upper OPERATION INDICATOR lamp blinks 6 times, then 2.5 seconds off, repeating
Outdoor thermistor error. One of the outdoor unit temperature sensors reads short circuit or open circuit while the compressor is running.
Manual wording: “Outdoor thermistors - The outdoor thermistors short or open circuit during the compressor operation.”
Documented for: MSZ-GL and MSY-GL indoor units paired with MUZ-GL or MUY-GL outdoor units
Likely causes, most common first
- Defective outdoor thermistor (discharge, defrost, ambient, fin or heat-exchanger sensor)
- Thermistor connector loose on the outdoor control board
- Broken thermistor lead 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
Identifying which outdoor sensor failed requires opening the outdoor unit and reading its board LEDs. 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.
Sources
- Indoor Unit Service Manual No. OBH732 Revised Edition-D - MSZ-GL/MSY-GL Series (Mitsubishi Electric, MSZ-GL06NA/GL09NA/GL12NA/GL15NA/GL18NA/GL24NA and MSY-GL09NA/GL12NA/GL15NA/GL18NA/GL24NA wall-mounted indoor units) · checked 2026-08-25
- Outdoor Unit Service Manual No. OBH733 Revised Edition-J - MUZ-GL/MUY-GL Series (Mitsubishi Electric, MUZ-GL09NA through MUZ-GL24NA, MUZ-GL09NAH through MUZ-GL24NAH, MUY-GL09NA through MUY-GL24NA single-zone outdoor units) · checked 2026-08-25