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Fujitsu Air Conditioner 99 Error Code
Reversing (4-way) valve error. Here is what it means and how to clear it, easiest fix first.
After switching between heating and cooling, the indoor coil temperature didn't move the way the board expected compared with room temperature, which suggests the reversing valve isn't changing over. A faulty valve or valve coil, a sensor or the outdoor board can be the cause.
Lamp pattern: on models that show faults with the indicator lamps, Fujitsu's tables for many current wall-mounted (RL/RLS/RLX, LZAH), compact ducted (RGLX) and RLF multi-zone units show this code as the Operation lamp flashing 9 times and the Timer lamp flashing 9 times, with the Economy lamp marked "continuous". Other Fujitsu units, such as universal-mount and ceiling-suspended models, use different lamps. A wired controller shows the code as a number. Shown as 99.1 on some ceiling cassette models. Fujitsu's older code set (for example older 9CQ/9RLQ/12CQ wall units, RMLQ-series multi-zone heads and some RCLX ceiling cassettes) uses different numbers for many faults, so always check the manual for your model.
How to fix Fujitsu 99
Reset the power at the breaker
Switch the system off with the remote, then turn off its circuit breaker in your home's main panel. Wait about 5 minutes, switch the breaker back on and restart the unit. If the code returns within a few minutes, write it down for the technician.
Record the details for the technician
Write down the exact code, the model numbers from the labels on the indoor and outdoor units, and what the system was doing when the code appeared. Leave the unit switched off if the code keeps returning, so a fault doesn't cause further damage.
When to call a technician
Reversing valve faults need an HVAC technician, and replacing the valve means opening the refrigerant circuit.
Parts that commonly cause 99
- 4-way reversing valve
- valve coil
- outdoor main board
Order parts by your exact model number so they fit.
Other Fujitsu air conditioner codes
- 11Indoor and outdoor units can't communicate
- 12Wired remote controller communication error
- 18External or Wi-Fi adapter communication error
- 32Indoor unit control board error
- 35MANUAL AUTO button stuck
- 41Room temperature sensor error
- 42Indoor coil temperature sensor error
- 51Indoor fan motor error
- 53Drain pump error
- 62Outdoor unit main board error
- 63Inverter error
- 65IPM (power module) protection
- 71-74Outdoor unit temperature sensor error
- 94Compressor overcurrent (trip detection)
- 95Compressor motor control error
- 97Outdoor fan motor error
- A1Discharge temperature too high
- A3Compressor temperature too high
- A5Low pressure error
Frequently asked questions
What does 99 mean on a Fujitsu air conditioner?
After switching between heating and cooling, the indoor coil temperature didn't move the way the board expected compared with room temperature, which suggests the reversing valve isn't changing over. A faulty valve or valve coil, a sensor or the outdoor board can be the cause.
Can I fix Fujitsu 99 myself?
Only the basic checks. You can safely try the steps above, but 99 usually points to a part or fault that needs a technician.
What if 99 keeps coming back?
A code that returns after a reset and the checks above usually means a part is wearing out. Note when 99 appears (which cycle, how often) and have your model number ready; it helps a technician bring the right part on the first visit.
Last reviewed 2026-10-19. Codes and steps can vary by model; check your owner's manual.