Fujitsu Mini-Split Code 6A
Hard lockoutShown as: OPERATION lamp blinks 6 times, TIMER lamp blinks 10 times, ECONOMY lamp blinking continuously
Display PCB communication error. The display board has received no communication from the I/O board for more than 10 seconds.
Manual wording: “Display P.C.B. Error - Communication not received from I/O PCB for more than 10 seconds.”
Documented for: RLF multi-zone indoor units
Likely causes, most common first
- Loose or erroneous molex plug connection between the display board and the I/O board
- Failed display PCB
What you can safely check yourself
- Turn the power off at the breaker for about 5 minutes and back on to see whether the code clears
When to call a technician
The display board harness is inside the unit. A technician has to reseat or replace it.
A Fujitsu mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- 410A Mini-Split Troubleshooting Guide (Part # 6-26-FG2020 Rev. 5/2019) (Fujitsu General America, Inc., All R410A Halcyon mini-splits: RGLX, RL2/RLS3/RLS3H/RLS3Y/RLB/RLXB/RLXEH wall mounted, RLF/RLF1 multi-zone indoor units, RLXFZ multi-zone outdoor units, RML/RMLQ, RULX/RSLX universal-mount, RCLX cassettes) · checked 2026-08-25