HVAC Code Lookup

Fujitsu fault codes

47 documented codes for Fujitsu mini-splits, each cited to the manufacturer's own manual. Find your code in the table, then jump to what it means, the likely causes, what you can safely check, and when to call a technician.

Fujitsu General builds the Halcyon (now AIRSTAGE) mini-split line sold in the US and Canada under both the Fujitsu and General names. Every R410A/R32 mini-split generation from the RL2/RLS2/RLS3/RLB/RLXB/RLF/RGLX era through the current LMAS/LZAS/LPAS/LUAS1 series uses the SAME two-number fault system: the OPERATION lamp blinks the first digit and the TIMER lamp blinks the second digit (while the ECONOMY lamp blinks fast/continuously), and the same number appears as a two-character code (11, 12, 41, A1, J2) on a wired remote controller. Older units (RLS, RLXS, CQ, RQ, R2, RL, RML, RMLQ, CLX, RLX, RLXQ, CL, RLQ) use a DIFFERENT blink-to-fault mapping for the same faults; those alternate patterns are recorded in each code's notes field.. Sold as Fujitsu General Halcyon and AIRSTAGE in North America.

Looking it up by flash count?

If you counted LED flashes rather than reading a code number, these are the codes that start with that many flashes:

  • 1 flashes: 11 (Serial communication error), 12 (Wired remote controller communication error), 15 (On multi-zone), 18 (External communication error)
  • 2 flashes: 21 (Number of wires and pipes error on a multi-zone system), 22 (Indoor unit capacity error on a multi-zone system), 23 (Combination error), 24 (Number of indoor units error or number of branch boxes error), 26 (Address setting error in the wired remote controller system), 29 (Connection unit number error)
  • 3 flashes: 32 (Indoor unit model information error / EEPROM access abnormal), 33 (Indoor unit motor electricity consumption detection error), 35 (Manual auto switch error), 39 (Indoor fan motor power supply error), 3A (Indoor unit communication circuit)
  • 4 flashes: 41 (Indoor room thermistor error), 42 (Indoor heat exchanger), 44 (Human sensor error)
  • 5 flashes: 51 (Indoor unit fan motor error), 53 (Drain pump error), 57 (Damper error), 58 (Intake grille error)
  • 6 flashes: 62 (Outdoor unit main PCB error), 63 (Inverter error), 64 (PFC circuit error or active filter error, depending on model), 65 (IPM), 6A (Display PCB communication error)
  • 7 flashes: 71 (Discharge thermistor error), 72 (Compressor thermistor error), 73 (Heat exchanger), 74 (Outdoor thermistor error), 75 (Suction gas thermistor error), 76 (2-way or 3-way valve thermistor error), 77 (Heat sink thermistor error)
  • 8 flashes: 82 (Sub-cool heat exchanger gas inlet or gas outlet thermistor error), 83 (Liquid pipe thermistor error), 84 (Current sensor error), 86 (High pressure switch error, or on 42k and 48k units a pressure sensor error)
  • 9 flashes: 94 (Over current error), 95 (Compressor motor control error), 97 (Outdoor unit fan motor error), 98 (Outdoor unit fan motor 2 error, on twin-fan condensers), 99 (4-way)
  • 10 flashes: A1 (Discharge temperature error), A3 (Compressor temperature error), A5 (Low pressure error)
  • 13 flashes: J2 (Branch box error)

Mini-Split codes

CodeMeaningSeverity
11OPERATION lamp blinks 1 time, TIMER lamp blinks 1 time, ECONOMY lamp blinking continuously/fastSerial communication errorSoft lockout
12OPERATION lamp blinks 1 time, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuouslyWired remote controller communication errorSoft lockout
15OPERATION lamp blinks 1 time, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuouslyOn multi-zoneWarning
18OPERATION lamp blinks 1 time, TIMER lamp blinks 8 times, ECONOMY lamp blinking continuouslyExternal communication errorSoft lockout
21OPERATION lamp blinks 2 times, TIMER lamp blinks 1 time, ECONOMY lamp blinking continuouslyNumber of wires and pipes error on a multi-zone systemSoft lockout
22OPERATION lamp blinks 2 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuouslyIndoor unit capacity error on a multi-zone systemSoft lockout
23OPERATION lamp blinks 2 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuouslyCombination errorHard lockout
24OPERATION lamp blinks 2 times, TIMER lamp blinks 4 times, ECONOMY lamp blinking continuouslyNumber of indoor units error or number of branch boxes errorSoft lockout
26OPERATION lamp blinks 2 times, TIMER lamp blinks 6 times, ECONOMY lamp blinking continuouslyAddress setting error in the wired remote controller systemSoft lockout
29OPERATION lamp blinks 2 times, TIMER lamp blinks 9 times, ECONOMY lamp blinking continuouslyConnection unit number errorSoft lockout
32OPERATION lamp blinks 3 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuouslyIndoor unit model information error / EEPROM access abnormalHard lockout
33OPERATION lamp blinks 3 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuouslyIndoor unit motor electricity consumption detection errorSoft lockout
35OPERATION lamp blinks 3 times, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuouslyManual auto switch errorWarning
39OPERATION lamp blinks 3 times, TIMER lamp blinks 9 times, ECONOMY lamp blinking continuouslyIndoor fan motor power supply errorSoft lockout
3AOPERATION lamp blinks 3 times, TIMER lamp blinks 10 times, ECONOMY lamp blinking continuouslyIndoor unit communication circuitSoft lockout
41OPERATION lamp blinks 4 times, TIMER lamp blinks 1 time, ECONOMY lamp blinking continuouslyIndoor room thermistor errorSoft lockout
42OPERATION lamp blinks 4 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuouslyIndoor heat exchangerSoft lockout
44OPERATION lamp blinks 4 times, TIMER lamp blinks 4 times, ECONOMY lamp blinking continuouslyHuman sensor errorWarning
51OPERATION lamp blinks 5 times, TIMER lamp blinks 1 time, ECONOMY lamp blinking continuouslyIndoor unit fan motor errorSoft lockout
53OPERATION lamp blinks 5 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuouslyDrain pump errorWarning
57OPERATION lamp blinks 5 times, TIMER lamp blinks 7 times, ECONOMY lamp blinking continuouslyDamper errorWarning
58OPERATION lamp blinks 5 times, TIMER lamp blinks 8 times, ECONOMY lamp blinking continuouslyIntake grille errorWarning
62OPERATION lamp blinks 6 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuouslyOutdoor unit main PCB errorHard lockout
63OPERATION lamp blinks 6 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuouslyInverter errorHard lockout
64OPERATION lamp blinks 6 times, TIMER lamp blinks 4 times, ECONOMY lamp blinking continuouslyPFC circuit error or active filter error, depending on modelHard lockout
65OPERATION lamp blinks 6 times, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuouslyIPMHard lockout
6AOPERATION lamp blinks 6 times, TIMER lamp blinks 10 times, ECONOMY lamp blinking continuouslyDisplay PCB communication errorHard lockout
71OPERATION lamp blinks 7 times, TIMER lamp blinks 1 time, ECONOMY lamp blinking continuouslyDischarge thermistor errorSoft lockout
72OPERATION lamp blinks 7 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuouslyCompressor thermistor errorSoft lockout
73OPERATION lamp blinks 7 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuouslyHeat exchangerSoft lockout
74OPERATION lamp blinks 7 times, TIMER lamp blinks 4 times, ECONOMY lamp blinking continuouslyOutdoor thermistor errorSoft lockout
75OPERATION lamp blinks 7 times, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuouslySuction gas thermistor errorSoft lockout
76OPERATION lamp blinks 7 times, TIMER lamp blinks 6 times, ECONOMY lamp blinking continuously2-way or 3-way valve thermistor errorSoft lockout
77OPERATION lamp blinks 7 times, TIMER lamp blinks 7 times, ECONOMY lamp blinking continuouslyHeat sink thermistor errorSoft lockout
82OPERATION lamp blinks 8 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuouslySub-cool heat exchanger gas inlet or gas outlet thermistor errorSoft lockout
83OPERATION lamp blinks 8 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuouslyLiquid pipe thermistor errorSoft lockout
84OPERATION lamp blinks 8 times, TIMER lamp blinks 4 times, ECONOMY lamp blinking continuouslyCurrent sensor errorSoft lockout
86OPERATION lamp blinks 8 times, TIMER lamp blinks 6 times, ECONOMY lamp blinking continuouslyHigh pressure switch error, or on 42k and 48k units a pressure sensor errorSoft lockout
94OPERATION lamp blinks 9 times, TIMER lamp blinks 4 times, ECONOMY lamp blinking continuouslyOver current errorSoft lockout
95OPERATION lamp blinks 9 times, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuouslyCompressor motor control errorHard lockout
97OPERATION lamp blinks 9 times, TIMER lamp blinks 7 times, ECONOMY lamp blinking continuouslyOutdoor unit fan motor errorSoft lockout
98OPERATION lamp blinks 9 times, TIMER lamp blinks 8 times, ECONOMY lamp blinking continuouslyOutdoor unit fan motor 2 error, on twin-fan condensersHard lockout
99OPERATION lamp blinks 9 times, TIMER lamp blinks 9 times, ECONOMY lamp blinking continuously4-waySoft lockout
A1OPERATION lamp blinks 10 times, TIMER lamp blinks 1 time, ECONOMY lamp blinking continuouslyDischarge temperature errorSoft lockout
A3OPERATION lamp blinks 10 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuouslyCompressor temperature errorSoft lockout
A5OPERATION lamp blinks 10 times, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuouslyLow pressure errorSoft lockout
J2OPERATION lamp blinks 13 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuouslyBranch box errorSoft lockout

Fujitsu mini-split code 11: Serial communication error

Soft lockoutShown as: OPERATION lamp blinks 1 time, TIMER lamp blinks 1 time, ECONOMY lamp blinking continuously/fast

Serial communication error. At start up the indoor unit (evaporator) and outdoor unit (condenser) are not talking to each other over the communication wire, so the system will not run.

Manual wording: “Communication Error - At Start up, evaporator and condenser are not communicating.”

Documented for: RL2, RLS2, RLS3, RLS3H, RLS3Y, RLB, RLXB, RLXEH, RLF, RLF1, RGLX, RLE, LUAS1, LMAS, LZBS, LZAS, LPAS series

Likely causes, most common first

  1. Bad or loose interconnecting wiring between the panel, condenser and evaporator (wire nuts and splices are not recommended by Fujitsu)
  2. Incorrect voltage at the panel, condenser or evaporator
  3. Open, shorted, or mis-landed communication conductor
  4. Failed indoor or outdoor control PCB

What you can safely check yourself

  • Check that the breaker and the outdoor disconnect switch are both on
  • Turn the system off at the breaker for about 5 minutes, then back on, and see whether the code returns

When to call a technician

Everything past a power reset on this code is line-voltage and communication-wire work at the disconnect, condenser and indoor unit. Have a licensed technician check the wiring and voltages.

Sources

Fujitsu mini-split code 12: Wired remote controller communication error

Soft lockoutShown as: OPERATION lamp blinks 1 time, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuously

Wired remote controller communication error. The indoor unit has not received a signal from the wired wall controller for more than 1 minute during normal operation.

Manual wording: “Wired Remote Controller Communication Error - When the indoor unit cannot receive the signal from the Wired Remote Control for more than 1 minute during normal operation.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB wall mounted, RLF/RLF1 multi-zone indoor units

Likely causes, most common first

  1. Loose or disconnected terminal between the wired remote controller and the indoor unit
  2. Broken or damaged remote controller cable
  3. Failed wired remote controller
  4. Failed indoor controller 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 remote controller cable lands on the indoor unit's control board terminals. Checking or reseating it means opening the electrical cover, which is a technician's job.

Source

Fujitsu mini-split code 15: On multi-zone

WarningShown as: OPERATION lamp blinks 1 time, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuously

On multi-zone (RLF/RLF1) systems: check-run unfinished. The installer's commissioning 'check run' was never completed, so the system refuses a run command from the remote. On RGLX ducted/cassette models the same pattern means automatic air flow adjustment error (the indoor fan could not complete its airflow learning routine).

Manual wording: “Check-Run Unfinished - When the operation command is inputted by the remote controller without check operation completion.”

Documented for: Multi-zone: ASU7/9/12RLF1, ASU18RLF, ASU15RLS, ASU15RLS2, ASU15RLF1, ASU24RLF, ARU/AUU/AGU RLF series, AOU48RLXFZ (E156). RGLX: AUU/ARU 12-48RGLX

Likely causes, most common first

  1. Multi-zone: the check-run commissioning procedure was not completed after installation
  2. Multi-zone: wrong indoor unit count connected, or an indoor unit was powered on part way through check run
  3. RGLX: indoor fan caught, obstructed, or the motor is locked
  4. RGLX: excessive ambient temperature around the indoor fan motor

What you can safely check yourself

  • Make sure the return air filter is clean and the supply and return grilles are open and unobstructed
  • Turn all indoor units off with their remotes, shut off the breaker/disconnect for 5 minutes, then restore power

When to call a technician

The check-run procedure has to be re-initialized by the installer at the outdoor unit and branch boxes. If this is a new install, call the installing contractor back - the system was never commissioned.

Sources

Fujitsu mini-split code 18: External communication error

Soft lockoutShown as: OPERATION lamp blinks 1 time, TIMER lamp blinks 8 times, ECONOMY lamp blinking continuously

External communication error. After receiving a signal from the external I/O PCB, the indoor controller has not received the same signal again for 15 seconds.

Manual wording: “External Communication Error - After receiving a signal from the external I/O PCB, the same signal has not been received for 15 seconds.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB wall mounted, RLF/RLF1 multi-zone

Likely causes, most common first

  1. Loose or removed connection between the controller PCB and the external I/O PCB
  2. Open cable or mis-wiring on the external I/O PCB
  3. Failed controller 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

This fault lives entirely on the accessory I/O board and its harness inside the unit. A technician must open the electrical box to inspect it.

Source

Fujitsu mini-split code 21: Number of wires and pipes error on a multi-zone system

Soft lockoutShown as: OPERATION lamp blinks 2 times, TIMER lamp blinks 1 time, ECONOMY lamp blinking continuously

Number of wires and pipes error on a multi-zone system. The number of wired zones does not match the number of piped zones, or wiring and piping have been crossed between rooms.

Manual wording: “Number of Wires and Pipes Error - When the operation command is inputted by the remote controller without check operation completion.”

Documented for: RLF / RLF1 multi-zone indoor units on RLXFZ multi-zone outdoor units

Likely causes, most common first

  1. Crossed wiring or crossed refrigerant piping between indoor units and the branch box or condenser
  2. An indoor unit that is piped but not wired (or wired but not piped)
  3. Operation command sent before check-run was completed

When to call a technician

This is an installation error. The wiring and piping between the outdoor unit, branch box and each indoor head must be traced and corrected by the installing contractor.

Source

Fujitsu mini-split code 22: Indoor unit capacity error on a multi-zone system

Soft lockoutShown as: OPERATION lamp blinks 2 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuously

Indoor unit capacity error on a multi-zone system. The total capacity of the connected indoor units is above the maximum or below the minimum the outdoor unit will accept.

Manual wording: “Indoor Unit Capacity Error - The total capacity of the indoor units has been exceeded or is under the minimum acceptable range.”

Documented for: RLF/RLF1, LPAS and LUAS1 multi-zone indoor units; AOU48RLXFZ shows E221

Likely causes, most common first

  1. Too much or too little total indoor capacity connected to the condenser
  2. Broken field wiring so the condenser cannot see one or more indoor units
  3. Failed indoor controller PCB on the missing zone

What you can safely check yourself

  • Check that every indoor head still has power (breaker and any zone disconnects on)
  • Turn the system off at the breaker for about 5 minutes, then back on

When to call a technician

Fujitsu notes that on multi-zone systems this code usually means the condenser has lost communication with one or more heads. Tracing that takes meter work on field wiring, so call a technician.

Sources

Fujitsu mini-split code 23: Combination error

Hard lockoutShown as: OPERATION lamp blinks 2 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuously

Combination error. The outdoor unit has detected that the indoor unit connected to it is not a matching model - for example a multi-zone indoor head wired to a single-zone condenser, or an unsupported condenser on a multi-zone system.

Manual wording: “Combination Error - The outdoor unit received a signal that the applied indoor unit is that of a multi type.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB wall mounted, RLF/RLF1 multi-zone

Likely causes, most common first

  1. Mismatched indoor and outdoor unit models
  2. Incorrect wiring between the indoor and outdoor units
  3. An unsupported multi-zone condenser installed for the indoor units fitted
  4. Failed outdoor main PCB (after the model match is confirmed correct)

When to call a technician

This means the equipment pairing or wiring is wrong. Only the installing contractor can verify model matching and correct the connection.

Source

Fujitsu mini-split code 24: Number of indoor units error or number of branch boxes error

Soft lockoutShown as: OPERATION lamp blinks 2 times, TIMER lamp blinks 4 times, ECONOMY lamp blinking continuously

Number of indoor units error or number of branch boxes error. The total number of connected indoor units is outside the allowed range of 2 to 8, or the two branch boxes report a different number of units.

Manual wording: “Number of Indoor Units Error / Number of Branch Boxes Error - When the total connection number of indoor units is outside of range between 2 and 8.”

Documented for: RLF / RLF1 multi-zone indoor units on branch-box (HFI Flex) systems

Likely causes, most common first

  1. Too many or too few indoor units connected for the outdoor unit
  2. A branch box not powered up
  3. Mismatch between branch box 1 and branch box 2 unit counts

What you can safely check yourself

  • Confirm the branch boxes still have power at their breakers or disconnects
  • Turn the whole system off at the breaker for about 5 minutes and back on

When to call a technician

Branch box configuration and unit counts are set at install. A technician has to verify the branch box power and the connected unit count.

Source

Fujitsu mini-split code 26: Address setting error in the wired remote controller system

Soft lockoutShown as: OPERATION lamp blinks 2 times, TIMER lamp blinks 6 times, ECONOMY lamp blinking continuously

Address setting error in the wired remote controller system. Auto-set and manually-set controller addresses are mixed in one remote controller group, or the same address number is duplicated in one group.

Manual wording: “Address Setting Error in Wired Remote Controller System - When the address number set by auto setting & manual setting are mixed in on RC group.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB, RLF/RLF1 with UTY-series wired remote controllers

Likely causes, most common first

  1. Wrong wiring connection within the remote controller group
  2. Auto address (00) and a manual address mixed in one remote controller group
  3. Duplicate remote controller addresses in one group
  4. Damaged indoor controller PCB

When to call a technician

Remote controller addressing is a commissioning setting done through the wall controller's service menus. Call the installing contractor.

Source

Fujitsu mini-split code 29: Connection unit number error

Soft lockoutShown as: OPERATION lamp blinks 2 times, TIMER lamp blinks 9 times, ECONOMY lamp blinking continuously

Connection unit number error. The number of indoor units connected in the remote controller group is outside the rule the control allows.

Manual wording: “Combination Unit Number Error - When the number of connecting indoor units are out of a specified rule.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB, RLF/RLF1 with wired remote controllers

Likely causes, most common first

  1. Wrong number of indoor units wired into the group
  2. Damaged indoor unit controller PCB

When to call a technician

The unit count is set by field wiring and controller addressing. This has to be corrected by the installing contractor.

Source

Fujitsu mini-split code 32: Indoor unit model information error / EEPROM access abnormal

Hard lockoutShown as: OPERATION lamp blinks 3 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuously

Indoor unit model information error / EEPROM access abnormal. The indoor board cannot read the memory chip that stores the unit's model data.

Manual wording: “EEPROM Error - Electronically erasable and programmable read only memory... -Check if the ground connection is proper.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB wall mounted, RLF/RLF1 multi-zone

Likely causes, most common first

  1. Poor or missing ground connection at the unit
  2. Electrical noise or harmonics on the power circuit (for example a nearby neon fixture or other noisy load)
  3. Failed indoor controller 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

If the code returns, the indoor control board or its ground has to be checked and the board is usually replaced. That is a technician's job.

Source

Fujitsu mini-split code 33: Indoor unit motor electricity consumption detection error

Soft lockoutShown as: OPERATION lamp blinks 3 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuously

Indoor unit motor electricity consumption detection error. The voltage or current the indoor fan motor is drawing has gone outside its allowed limits.

Manual wording: “Indoor unit motor electricity consumption detection error - When the voltage value or current value of the motor go beyond the limits.”

Documented for: AUU18-48RGLX, ARU12-48RGLX

Likely causes, most common first

  1. Indoor fan caught, dropped off its shaft, or the motor is locked
  2. Excessively high ambient temperature around the fan motor from nearby equipment
  3. Failed indoor fan motor
  4. Failed indoor controller PCB

What you can safely check yourself

  • Replace or clean the return air filter
  • Make sure supply and return grilles are open and not blocked by furniture or drapes
  • Turn the power off at the breaker for about 5 minutes and back on

When to call a technician

Checking the blower wheel and motor windings means removing panels with the unit powered. Have a technician do it.

Source

Fujitsu mini-split code 35: Manual auto switch error

WarningShown as: OPERATION lamp blinks 3 times, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuously

Manual auto switch error. The MANUAL AUTO button on the indoor unit has read as pressed for 60 or more consecutive seconds.

Manual wording: “Manual Auto Switch Error - When the manual auto switch becomes on for 60 or more consecutive seconds.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB wall mounted, RLF/RLF1 multi-zone

Likely causes, most common first

  1. The manual/auto button is physically stuck in, jammed by the front panel, or held down
  2. Failed manual auto switch
  3. Failed indoor controller PCB

What you can safely check yourself

  • Make sure the front panel and filter access cover are fully closed and seated, so nothing is holding the MANUAL AUTO button in
  • Look at the MANUAL AUTO button on the indoor unit and confirm it is not stuck in the pressed position
  • Turn the power off at the breaker for about 5 minutes and back on

When to call a technician

If the button is not physically stuck, the switch or the control board is at fault and a technician must test it.

Source

Fujitsu mini-split code 39: Indoor fan motor power supply error

Soft lockoutShown as: OPERATION lamp blinks 3 times, TIMER lamp blinks 9 times, ECONOMY lamp blinking continuously

Indoor fan motor power supply error. The indoor board has lost the supply feeding the fan motor, usually from a voltage drop, electrical noise, or an open connector.

Manual wording: “Check external cause at indoor and outdoor units (voltage drop or noise) ... Check if cable is open. (Upon correcting removed connector, reset the power)”

Documented for: AUU18-48RGLX, ARU12-48RGLX

Likely causes, most common first

  1. Voltage drop or electrical noise from a large load sharing the same circuit
  2. Defective contact or leakage current in the power supply circuit
  3. Connector removed, mis-connected, or an open cable to the fan motor

What you can safely check yourself

  • Check whether a large appliance shares the same circuit and started at the same time the fault appeared
  • Turn the power off at the breaker for about 5 minutes and back on

When to call a technician

Connector and supply-circuit checks are inside the powered electrical box. Leave that to a technician.

Source

Fujitsu mini-split code 3A: Indoor unit communication circuit

Soft lockoutShown as: OPERATION lamp blinks 3 times, TIMER lamp blinks 10 times, ECONOMY lamp blinking continuously

Indoor unit communication circuit (wired remote controller) error. The indoor unit sees an abnormal remote controller group configuration, or cannot find the primary remote controller.

Manual wording: “Indoor Unit Communication Circuit (WRC) Error - When the indoor unit detects the configuration of the remote controller group is abnormal or the indoor unit detects lack of primary remote controller.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB wall mounted with UTY-series wired remote controllers

Likely causes, most common first

  1. Disconnected or shorted cable between the wired remote controller and the indoor unit, or between indoor units
  2. Failed wired remote controller (indicated when 12 VDC is present at controller PCB connector CNC01)
  3. Failed indoor controller PCB (indicated when 0 VDC is present at CNC01)

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

Diagnosing this requires metering 12 VDC at a board connector inside the indoor unit. A technician must do that.

Source

Fujitsu mini-split code 41: Indoor room thermistor error

Soft lockoutShown as: OPERATION lamp blinks 4 times, TIMER lamp blinks 1 time, ECONOMY lamp blinking continuously

Indoor room thermistor error. The room temperature sensor in the indoor unit has read an impossible temperature, meaning it is open or shorted.

Manual wording: “Indoor Room Thermistor Error - Room temperature thermistor detected an abnormal temperature.”

Documented for: RGLX, RL2/RLS2/RLS3/RLB/RLXB wall mounted, RLF/RLF1 multi-zone

Likely causes, most common first

  1. Open or shorted room temperature thermistor
  2. Thermistor resistance out of specification
  3. Failed indoor controller 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 room thermistor is behind the indoor unit's front panel and has to be ohm-checked against Fujitsu's resistance table. Have a technician replace it.

Source

Fujitsu mini-split code 42: Indoor heat exchanger

Soft lockoutShown as: OPERATION lamp blinks 4 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuously

Indoor heat exchanger (pipe) thermistor error. The evaporator coil pipe sensor has read an abnormal temperature, meaning it is open or shorted.

Manual wording: “Indoor Heat Ex. (Pipe) Thermistor Error - Evaporator pipe thermistor detected an abnormal temperature.”

Documented for: RGLX, RL2/RLS2/RLS3/RLB/RLXB wall mounted, RLF/RLF1 multi-zone

Likely causes, most common first

  1. Open or shorted indoor pipe thermistor
  2. Thermistor resistance out of specification
  3. Failed indoor controller 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 pipe thermistor clips onto the evaporator coil behind the indoor unit's casing. Replacing it is a technician's job.

Source

Fujitsu mini-split code 44: Human sensor error

WarningShown as: OPERATION lamp blinks 4 times, TIMER lamp blinks 4 times, ECONOMY lamp blinking continuously

Human sensor error. The occupancy (human) sensor on the indoor unit is not responding correctly to the control board.

Manual wording: “Human Sensor error - Check if the connector connection and if cable is open”

Documented for: RGLX indoor units fitted with the human/occupancy sensor option

Likely causes, most common first

  1. Loose or removed human sensor connector
  2. Erroneous connection at the sensor plug
  3. Open sensor cable
  4. Failed sensor, or failed main 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

Diagnosing this requires continuity and 5 VDC checks at connector CN67 on the main board. That is technician work.

Source

Fujitsu mini-split code 51: Indoor unit fan motor error

Soft lockoutShown as: OPERATION lamp blinks 5 times, TIMER lamp blinks 1 time, ECONOMY lamp blinking continuously

Indoor unit fan motor error. The actual indoor fan speed stayed below one third of the target speed for more than 56 seconds, so the unit shut down.

Manual wording: “Indoor Unit Fan Motor Error - When the condition that actual frequency of indoor fan is below 1/3 of target frequency is continued more than 56 seconds.”

Documented for: RL2, RLS2, RLS3, RLB/RLXB, RLF, RLF1, RGLX, RLE, LUAS1, LMAS, LZBS, LZAS, LPAS series

Likely causes, most common first

  1. Indoor fan wheel jammed, obstructed, or the motor is locked
  2. Excessive ambient temperature around the fan motor
  3. Indoor fan motor windings out of specification
  4. Failed indoor controller PCB

What you can safely check yourself

  • Clean or replace the indoor unit's air filters - a heavily blocked filter loads the blower
  • Make sure the indoor unit's air inlet and outlet are not blocked
  • Turn the power off at the breaker for about 5 minutes and back on, then see whether the code returns

When to call a technician

Fujitsu's own next step is to spin the blower by hand and ohm the motor windings inside the unit. Have a technician do that.

Sources

Fujitsu mini-split code 53: Drain pump error

WarningShown as: OPERATION lamp blinks 5 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuously

Drain pump error. The condensate float switch has stayed made for more than 3 minutes, meaning water is backing up in the drain pan.

Manual wording: “Drain Pump Error - When the float switch is on for more than 3 minutes, error will trigger.”

Documented for: RLF series, RGLX series, LUAS1 series ducted and cassette indoor units fitted with a condensate pump

Likely causes, most common first

  1. Clogged condensate drain hose or drain line
  2. Float switch fouled with dust or debris, or stuck
  3. Failed condensate pump
  4. Loose or pinched float switch connector (CN9) or wire
  5. Failed indoor controller PCB

What you can safely check yourself

  • Check the condensate drain line outside for a blockage, kink, or ice at the discharge point
  • Check that the drain hose has a continuous downward slope and is not crushed
  • Turn the unit off at the breaker until the pan has drained, then restore power

When to call a technician

Clearing a plugged drain inside the unit, testing the float switch, or replacing the pump means opening the indoor unit. Get a technician if the outside end of the drain line is clear.

Sources

Fujitsu mini-split code 57: Damper error

WarningShown as: OPERATION lamp blinks 5 times, TIMER lamp blinks 7 times, ECONOMY lamp blinking continuously

Damper error. The limit switch did not confirm the upper airflow damper reached the closed position.

Manual wording: “Damper Error - When limit switch was not able to detect the closing though the damper is closed. (Upper air flow)”

Documented for: RLF multi-zone indoor units with a motorized upper airflow damper

Likely causes, most common first

  1. Something obstructing the damper's travel
  2. Damper mechanism binding or damaged
  3. Loose connector CN18, or a shorted/pinched wire
  4. Failed limit switch

What you can safely check yourself

  • Look for an obvious obstruction in front of the indoor unit's air outlet louvers

When to call a technician

The damper limit switch and its harness are inside the indoor unit's casing. A technician must check them.

Source

Fujitsu mini-split code 58: Intake grille error

WarningShown as: OPERATION lamp blinks 5 times, TIMER lamp blinks 8 times, ECONOMY lamp blinking continuously

Intake grille error. The micro switch that proves the intake grille is closed read open while the compressor was running.

Manual wording: “Intake Grille Error - When the micro switch is detected open while running the compressor.”

Documented for: RLF multi-zone and RLS3/RLB/RLXB wall mounted indoor units with a powered intake grille

Likely causes, most common first

  1. Intake grille or front panel not fully closed and latched
  2. Failed limit / micro switch
  3. Loose connector CN11 or damaged wire
  4. Failed indoor controller PCB

What you can safely check yourself

  • Open and re-close the intake grille or front panel until it clicks fully shut on both sides
  • Make sure the filters are seated properly so the grille can close all the way
  • Turn the power off at the breaker for about 5 minutes and back on

When to call a technician

If the grille is definitely latched and the code stays, the micro switch or its wiring has failed and a technician must replace it.

Source

Fujitsu mini-split code 62: Outdoor unit main PCB error

Hard lockoutShown as: OPERATION lamp blinks 6 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuously

Outdoor unit main PCB error. The outdoor control board failed to access its EEPROM memory after the unit started.

Manual wording: “Outdoor Unit Main PCB Error - Access to EEPROM failed due to some cause after outdoor unit started.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB, RLF/RLF1 outdoor units

Likely causes, most common first

  1. Voltage drop or poor ground connection at the outdoor unit
  2. Failed outdoor main PCB

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and the breaker for about 5 minutes, then restore power and see whether the code clears

When to call a technician

Fujitsu's own procedure after a reset is to check the supply voltage and ground at the condenser and then replace the main board. That is technician work at line voltage.

Source

Fujitsu mini-split code 63: Inverter error

Hard lockoutShown as: OPERATION lamp blinks 6 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuously

Inverter error. The outdoor main board received an error report from the inverter (transistor) board that drives the compressor.

Manual wording: “Inverter Error - Error information received from the inverter PCB.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB, RLF/RLF1 outdoor units

Likely causes, most common first

  1. Loose molex connectors on the inverter PCB
  2. Wiring fault between the power supply, filter PCB and transistor PCB
  3. Failed transistor PCB
  4. Failed main PCB or filter PCB

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and the breaker for about 5 minutes, then restore power

When to call a technician

The inverter section holds high-voltage DC capacitors that stay charged after power is removed. Never open the outdoor electrical cover; call a licensed technician.

Source

Fujitsu mini-split code 64: PFC circuit error or active filter error, depending on model

Hard lockoutShown as: OPERATION lamp blinks 6 times, TIMER lamp blinks 4 times, ECONOMY lamp blinking continuously

PFC circuit error or active filter error, depending on model. On 9RLS3/12RLS3 the inverter output DC voltage went above 415 V for over 3 seconds; on 15RLS3, 15RLS3H and 30RLXEH the inverter input DC voltage went above 425 V or below 80 V, or a momentary power interruption occurred at low voltage.

Manual wording: “PFC Circuit Error (9/12RLS3) - When inverter output DC voltage is higher than 415V for over 3 seconds, the compressor stops. If the same operation is repeated 5 times, the compressor stops permanently.”

Documented for: 9RLS3, 12RLS3 (PFC circuit error); 15RLS3, 15RLS3H, 30RLXEH (active filter error); RGLX models (active filter / PFC circuit error)

Likely causes, most common first

  1. Voltage drop, brownout, or electrical noise on the supply to the indoor or outdoor unit
  2. Momentary power interruption
  3. Loose or erroneous connector connection in the outdoor electrical box
  4. Failed active filter module (ACTPM) or main PCB

What you can safely check yourself

  • Note whether the fault followed a power outage, brownout, or generator switchover
  • Turn the power off at the outdoor disconnect and the breaker for about 5 minutes, then restore power

When to call a technician

If the compressor repeats this five times it stops permanently. Diagnosing needs live DC measurements in the inverter section, so call a licensed technician.

Source

Fujitsu mini-split code 65: IPM

Hard lockoutShown as: OPERATION lamp blinks 6 times, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuously

IPM (intelligent power module) error. An abnormal current was detected at the power module driving the compressor, often because heat cannot escape the outdoor unit.

Manual wording: “IPM Error - Abnormal current value at the IPM is detected. Heat radiation is blocked (inlet/outlet).”

Documented for: RGLX, RL2/RLS3/RLB/RLXB, RLF/RLF1 outdoor units

Likely causes, most common first

  1. Blocked heat radiation at the outdoor unit inlet or outlet
  2. Dirty or clogged outdoor heat exchanger coil
  3. Loose connections on the outdoor unit electrical components
  4. Failed outdoor fan
  5. Compressor windings out of specification, or a failed IPM

What you can safely check yourself

  • Clear leaves, grass clippings, snow, or stored items away from the outdoor unit so air can move freely through the coil and out of the fan
  • Make sure nothing has been placed on top of or against the condenser
  • Turn the power off at the disconnect and breaker for about 5 minutes, then restore power

When to call a technician

Anything beyond clearing airflow - coil cleaning, checking the fan, or measuring compressor resistance - needs a licensed technician.

Source

Fujitsu mini-split code 6A: Display PCB communication error

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

  1. Loose or erroneous molex plug connection between the display board and the I/O board
  2. 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.

Source

Fujitsu mini-split code 71: Discharge thermistor error

Soft lockoutShown as: OPERATION lamp blinks 7 times, TIMER lamp blinks 1 time, ECONOMY lamp blinking continuously

Discharge thermistor error. The sensor on the compressor discharge pipe read as open or shorted, either at power up or while the compressor was running.

Manual wording: “Discharge Thermistor Error - When discharge pipe temperature thermistor open or short-circuit is detected at power on or while running the compressor.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB, RLF/RLF1 outdoor units

Likely causes, most common first

  1. Loose, removed, or wrongly landed thermistor connector
  2. Open or shorted discharge thermistor
  3. Failed outdoor main PCB

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power

When to call a technician

The discharge thermistor sits on hot refrigerant piping inside the condenser cabinet. Replacing it is a technician's job.

Source

Fujitsu mini-split code 72: Compressor thermistor error

Soft lockoutShown as: OPERATION lamp blinks 7 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuously

Compressor thermistor error. The compressor body temperature sensor is open or short-circuited.

Manual wording: “Compressor Thermistor Error - Compressor temperature thermistor is open or short-circuited while power is on or running the compressor.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB, RLF/RLF1 outdoor units

Likely causes, most common first

  1. Erroneous connection or removed connector at the compressor thermistor
  2. Thermistor resistance out of specification
  3. Failed outdoor main PCB

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power

When to call a technician

The sensor mounts on the compressor shell inside the condenser. Only a technician should replace it.

Source

Fujitsu mini-split code 73: Heat exchanger

Soft lockoutShown as: OPERATION lamp blinks 7 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuously

Heat exchanger (pipe) thermistor error at the outdoor unit. The outdoor coil pipe sensor is open or short-circuited.

Manual wording: “Heat Exchanger (Pipe) Thermistor Error - When heat exchanger temperature thermistor open or short-circuit is detected at power up or while running the compressor.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB, RLF/RLF1 outdoor units. On 30RLXEH this position also covers heat exchanger middle temperature and heat exchanger liquid temperature thermistor errors

Likely causes, most common first

  1. Loose or erroneous connector connection
  2. Open or shorted outdoor pipe thermistor
  3. Failed outdoor main PCB

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power

When to call a technician

Replacing the outdoor coil sensor means working inside the condenser cabinet. Call a technician.

Source

Fujitsu mini-split code 74: Outdoor thermistor error

Soft lockoutShown as: OPERATION lamp blinks 7 times, TIMER lamp blinks 4 times, ECONOMY lamp blinking continuously

Outdoor thermistor error. The outdoor ambient air temperature sensor is open or short-circuited.

Manual wording: “Outdoor Thermistor Error - When outdoor temperature thermistor is open or a short-circuit is detected at power on or while running the compressor.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB, RLF/RLF1 outdoor units

Likely causes, most common first

  1. Loose or erroneous connector connection
  2. Open or shorted outdoor air thermistor
  3. Failed outdoor main PCB

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power

When to call a technician

The outdoor air sensor and its plug are inside the condenser cabinet. Have a technician check and replace it.

Source

Fujitsu mini-split code 75: Suction gas thermistor error

Soft lockoutShown as: OPERATION lamp blinks 7 times, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuously

Suction gas thermistor error. The suction gas temperature sensor has shorted or gone open.

Manual wording: “Suction Gas Thermistor Error - Suction gas temperature thermistor has shorted or open detected.”

Documented for: RLF/RLF1 multi-zone systems on RLXFZ outdoor units

Likely causes, most common first

  1. Loose or erroneous molex plug connection
  2. Thermistor resistance out of specification
  3. Failed outdoor main PCB

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power

When to call a technician

The suction gas sensor is on refrigerant piping in the condenser. A technician must check and replace it.

Source

Fujitsu mini-split code 76: 2-way or 3-way valve thermistor error

Soft lockoutShown as: OPERATION lamp blinks 7 times, TIMER lamp blinks 6 times, ECONOMY lamp blinking continuously

2-way or 3-way valve thermistor error. The temperature sensor on a service valve is open or short-circuited while power is on or the compressor is running.

Manual wording: “2-Way Valve Thermistor Error - When 2-way valve temperature thermistor is open or short-circuited while power is on or while running the compressor.”

Documented for: RLF/RLF1, LPAS and LUAS1 multi-zone indoor units; AOU18/24/36RLXFZ and AOU24/36RML outdoor units

Likely causes, most common first

  1. Erroneous connection or removed connector at the valve thermistor
  2. Thermistor resistance out of specification
  3. Failed outdoor main PCB

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power

When to call a technician

These sensors sit on the service valves inside the condenser or branch box and are ohm-checked against Fujitsu's resistance chart. That is technician work.

Sources

Fujitsu mini-split code 77: Heat sink thermistor error

Soft lockoutShown as: OPERATION lamp blinks 7 times, TIMER lamp blinks 7 times, ECONOMY lamp blinking continuously

Heat sink thermistor error. The heat sink temperature sensor built into the power module is open or shorted.

Manual wording: “Heat Sink Thermistor Error - Heat sink temperature thermistor (built-in IPM) is open or shorted.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB, RLF/RLF1 outdoor units

Likely causes, most common first

  1. Failed inverter PCB (the sensor is built into the module on wall-mounted models)
  2. Erroneous connection or removed connector
  3. Thermistor resistance out of specification

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power

When to call a technician

On wall-mounted models this sensor is part of the inverter board, so the fix is a board replacement by a licensed technician.

Source

Fujitsu mini-split code 82: Sub-cool heat exchanger gas inlet or gas outlet thermistor error

Soft lockoutShown as: OPERATION lamp blinks 8 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuously

Sub-cool heat exchanger gas inlet or gas outlet thermistor error. One of the sub-cooling heat exchanger gas sensors is shorted or open.

Manual wording: “Sub-Cool Heat Ex. Gas Inlet Thermistor Error / Sub Cool Heat Ex. Gas Outlet Thermistor Error - Sub cooling heat exchanger gas inlet temperature thermistor short or open detected.”

Documented for: RLF/RLF1 multi-zone systems on larger RLXFZ outdoor units

Likely causes, most common first

  1. Erroneous connection or removed connector
  2. Thermistor resistance out of specification
  3. Failed outdoor main PCB

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power

When to call a technician

Sub-cool circuit sensors are deep inside the outdoor unit. A technician must diagnose this.

Source

Fujitsu mini-split code 83: Liquid pipe thermistor error

Soft lockoutShown as: OPERATION lamp blinks 8 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuously

Liquid pipe thermistor error. The heat exchanger liquid pipe sensor is shorted or open.

Manual wording: “Liquid Pipe Thermistor Error - Heat exchanger liquid pipe thermistor short or open detected.”

Documented for: RLF/RLF1 multi-zone systems on RLXFZ outdoor units

Likely causes, most common first

  1. Erroneous connection or removed connector
  2. Thermistor resistance out of specification
  3. Failed outdoor main PCB

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power

When to call a technician

The liquid pipe sensor is on refrigerant piping inside the outdoor unit. Have a technician replace it.

Source

Fujitsu mini-split code 84: Current sensor error

Soft lockoutShown as: OPERATION lamp blinks 8 times, TIMER lamp blinks 4 times, ECONOMY lamp blinking continuously

Current sensor error. The input current sensor read 0 amps while the inverter compressor was running above 56 rps, one minute after start-up (outside of defrost).

Manual wording: “Current Sensor Error - When input current sensor has detected 0A, while the inverter compressor is operating at higher than 56rps, after 1 minute upon starting the compressor.”

Documented for: RGLX, RL2/RLS3/RLB/RLXB, RLF/RLF1 outdoor units

Likely causes, most common first

  1. Loose terminal connection at the outdoor unit
  2. Connector removed from the current transformer
  3. Erroneous connection
  4. Failed current sensor or main PCB

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power

When to call a technician

The current sensor wraps the compressor supply conductor inside the electrical box. Only a licensed technician should open that.

Source

Fujitsu mini-split code 86: High pressure switch error, or on 42k and 48k units a pressure sensor error

Soft lockoutShown as: OPERATION lamp blinks 8 times, TIMER lamp blinks 6 times, ECONOMY lamp blinking continuously

High pressure switch error, or on 42k and 48k units a pressure sensor error. The high pressure switch was seen open for longer than 10 seconds after power was turned on.

Manual wording: “High Pressure Switch Error - When the pressure switch is detected open for longer than 10 seconds after the power is turned on.”

Documented for: 18/24/30/36 models show high pressure switch error; 42/48 models show pressure sensor error. RGLX, RLS3/RLB/RLXB, RLF/RLF1

Likely causes, most common first

  1. System high side pressure genuinely too high (blocked condenser airflow, dirty coil, overcharge)
  2. Failed or open high pressure switch
  3. Wiring or voltage fault at the pressure switch

What you can safely check yourself

  • Clear leaves, snow, or debris away from the outdoor coil and fan so the unit can reject heat
  • Make sure nothing is stacked on or against the outdoor unit
  • Turn the power off at the disconnect for 3 to 5 minutes and back on

When to call a technician

Never jumper or bypass the high pressure switch - it is a safety device. Measuring switch voltage and resistance, or checking system pressures, requires a licensed technician with gauges.

Source

Fujitsu mini-split code 94: Over current error

Soft lockoutShown as: OPERATION lamp blinks 9 times, TIMER lamp blinks 4 times, ECONOMY lamp blinking continuously

Over current error (trip detection). The compressor tripped on overcurrent immediately after starting, ten times consecutively, so the unit shut down.

Manual wording: “Over Current Error - Protection stop by overcurrent generation after inverter compressor start processing completed generated consecutively 10 times.”

Documented for: RL2, RLS2, RLS3, RLB/RLXB, RLF, RLF1, RGLX, RLE, LUAS1, LMAS, LZBS, LZAS, LPAS series

Likely causes, most common first

  1. Clogged outdoor heat exchanger restricting airflow
  2. Defective condenser fan motor
  3. Discharged air being pulled back into the outdoor unit (short cycling of air)
  4. Compressor or inverter fault

What you can safely check yourself

  • Check the outdoor coil for heavy dirt, cottonwood, grass clippings, or leaves and clear away anything blocking it
  • Make sure the outdoor unit has clearance on all sides and its discharge air is not blowing into a wall or fence and back into the coil
  • Turn the power off at the disconnect for about 5 minutes, then restore power

When to call a technician

If airflow is clear and the code returns, the condenser fan motor or the compressor circuit has to be tested by a licensed technician.

Sources

Fujitsu mini-split code 95: Compressor motor control error

Hard lockoutShown as: OPERATION lamp blinks 9 times, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuously

Compressor motor control error (rotor position detection error). The control cannot keep track of the compressor rotor position, so the compressor stops; if it repeats within 40 seconds of restart it stops again and can go to a permanent stop.

Manual wording: “Compressor Motor Control Error - If the detected rotor location is out of phase with actual rotor location more than 90 degrees, the compressor stops.”

Documented for: RL2, RLS2, RLS3, RLB/RLXB, RLF, RLF1, RGLX, RLE, LUAS1, LMAS, LZBS, LZAS, LPAS series

Likely causes, most common first

  1. Connector removed or loose on the compressor leads
  2. Erroneous connection at the compressor terminals
  3. Open compressor lead cable
  4. Failed compressor or inverter board

What you can safely check yourself

  • Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power

When to call a technician

This is a compressor-drive fault. Compressor terminal and winding checks are high-voltage work for a licensed technician only.

Sources

Fujitsu mini-split code 97: Outdoor unit fan motor error

Soft lockoutShown as: OPERATION lamp blinks 9 times, TIMER lamp blinks 7 times, ECONOMY lamp blinking continuously

Outdoor unit fan motor error. The outdoor fan turned slower than 100 RPM within 20 seconds of starting; after three repeats inside 60 seconds the compressor and fan both stop.

Manual wording: “Outdoor Unit Fan Motor Error - When outdoor fan motor rotation speed is less than 100 RPMs in 20 seconds after fan motor starts, fan motor stops.”

Documented for: RL2, RLS2, RLS3, RLB/RLXB, RLF, RLF1, RGLX, RLE, LUAS1, LMAS, LZBS, LZAS, LPAS series

Likely causes, most common first

  1. Outdoor fan blade obstructed, iced, or the motor is locked
  2. Excessive ambient temperature around the fan motor from nearby heat-producing equipment
  3. Outdoor fan motor windings out of specification, or missing DC supply to the motor
  4. Failed outdoor main PCB

What you can safely check yourself

  • With the power off at the disconnect, look for leaves, ice, or debris jamming the outdoor fan blade
  • Clear snow and ice buildup from around and on top of the outdoor unit
  • Turn the power off at the disconnect for about 5 minutes, then restore power

When to call a technician

Fujitsu's next steps are ohming the fan motor windings and checking DC voltage to the motor. That means a licensed technician.

Sources

Fujitsu mini-split code 98: Outdoor unit fan motor 2 error, on twin-fan condensers

Hard lockoutShown as: OPERATION lamp blinks 9 times, TIMER lamp blinks 8 times, ECONOMY lamp blinking continuously

Outdoor unit fan motor 2 error, on twin-fan condensers. The second outdoor fan turned slower than 100 RPM within 20 seconds of starting; repeated five times in a row, the compressor and fan stop permanently.

Manual wording: “Outdoor Unit Fan Motor 2 Error - When the outdoor fan rotation speed is less than 100 RPMs in 20 seconds after the fan motor starts, the fan will stop... If above repeats 5 times in a row, compressor and fan stop permanently.”

Documented for: Twin-fan outdoor units: larger RGLX, RLXB and RLXFZ condensers

Likely causes, most common first

  1. Second outdoor fan blade obstructed, iced, or the motor is locked
  2. Excessive ambient temperature around the fan motor
  3. Fan motor windings out of specification, or missing DC voltage to the motor
  4. Failed outdoor main PCB

What you can safely check yourself

  • With the power off at the disconnect, look for debris or ice jamming either outdoor fan blade
  • Turn the power off at the disconnect for about 5 minutes, then restore power

When to call a technician

After the permanent stop this needs a technician to test the motor and reset the system.

Source

Fujitsu mini-split code 99: 4-way

Soft lockoutShown as: OPERATION lamp blinks 9 times, TIMER lamp blinks 9 times, ECONOMY lamp blinking continuously

4-way (reversing) valve error. The control compared indoor coil temperature to room temperature and twice found the system running backwards for the selected mode, so the compressor stopped.

Manual wording: “4-Way Valve Error - When the indoor heat exchanger temperature is compared with the room temperature, and either following condition is detected continuously two times, the compressor stops.”

Documented for: RL2, RLS2, RLS3, RLB/RLXB, RLF, RLF1, RGLX, RLE, LUAS1, LMAS, LZBS, LZAS, LPAS series

Likely causes, most common first

  1. 4-way valve stuck or not shifting
  2. Failed 4-way valve solenoid coil, or no voltage to the coil
  3. Loose molex plug at the valve coil
  4. Thermistor reading wrong (indoor coil or room sensor)

What you can safely check yourself

  • Note which mode the system was in when it failed - Fujitsu uses that to separate a valve fault from a control fault
  • Turn the power off at the disconnect for about 5 minutes and back on, then run the system and see whether it heats or cools correctly

When to call a technician

Testing the reversing valve, its solenoid coil, and the coil voltage is refrigeration and line-voltage work for a licensed technician.

Sources

Fujitsu mini-split code A1: Discharge temperature error

Soft lockoutShown as: OPERATION lamp blinks 10 times, TIMER lamp blinks 1 time, ECONOMY lamp blinking continuously

Discharge temperature error. The compressor discharge line reached 230 F (110 C) during operation twice within 24 hours, so the system stopped to protect the compressor.

Manual wording: “Discharge Temperature Error - Protection stop by discharge temperature 230F (110C) during compressor operation generated 2 times within 24 hours.”

Documented for: RL2, RLS2, RLS3, RLB/RLXB, RLF, RLF1, RGLX, RLE, LUAS1, LMAS, LZBS, LZAS, LPAS series

Likely causes, most common first

  1. Closed or partly closed 3-way service valve
  2. Restricted electronic expansion valve or clogged strainer
  3. Outdoor fan or heat exchanger not rejecting heat (dirty coil, blocked airflow)
  4. Low refrigerant charge or a refrigerant leak
  5. Failed discharge thermistor

What you can safely check yourself

  • Clear anything blocking airflow at the outdoor unit - leaves, snow, stored items, overgrown shrubs
  • Check the outdoor coil for heavy dirt or cottonwood buildup
  • Turn the power off at the disconnect for about 5 minutes, then restore power

When to call a technician

Fujitsu's checklist is service valves, expansion valve, strainer, and a leak check with gauges. All of that is licensed refrigeration work - do not open service valves yourself.

Sources

Fujitsu mini-split code A3: Compressor temperature error

Soft lockoutShown as: OPERATION lamp blinks 10 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuously

Compressor temperature error. The compressor body reached 226 F (107.8 C) during operation twice within 24 hours and the system stopped to protect it.

Manual wording: “Compressor Temperature Thermistor Error - Protection stop by compressor temperature 226F (107.8C) during compressor operation generated 2 times within 24 hours.”

Documented for: RL2, RLS2, RLS3, RLB/RLXB, RLF, RLF1, RGLX, RLE, LUAS1, LMAS, LZBS, LZAS, LPAS series

Likely causes, most common first

  1. Closed or partly closed 3-way service valve
  2. Restricted electronic expansion valve or clogged strainer
  3. Outdoor fan or heat exchanger not rejecting heat
  4. Low refrigerant charge or a leak
  5. Loose connection at the compressor thermistor

What you can safely check yourself

  • Clear leaves, snow, and debris from around the outdoor unit and off the coil
  • Turn the power off at the disconnect for about 5 minutes, then restore power

When to call a technician

Service valve position, expansion valve, strainer and charge level all require gauges and a refrigeration license. Call a technician.

Sources

Fujitsu mini-split code A5: Low pressure error

Soft lockoutShown as: OPERATION lamp blinks 10 times, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuously

Low pressure error. Suction pressure stayed at or below 7.35 PSI for 5 minutes, repeating 5 times within 2 hours, so the system stopped.

Manual wording: “Low Pressure Error - Protection stop by suction pressure 7.35 PSI continued for 5 minutes, repeats 5 times within 2 hours.”

Documented for: Single-zone (1-to-1) matched systems; RGLX, RLS3/RLB/RLXB, RLF/RLF1

Likely causes, most common first

  1. Closed or partly closed 3-way (gas side) service valve
  2. Clogged strainer
  3. Failed electronic expansion valve coil
  4. Low refrigerant charge or a refrigerant leak
  5. Failed suction pressure sensor

What you can safely check yourself

  • Note the outdoor temperature when the code appeared - Fujitsu says this code only shows up when outdoor ambient drops below 32 F
  • Turn the power off at the disconnect for about 5 minutes, then restore power

When to call a technician

Fujitsu classes A5 as a fix-on-fail code that must be serviced on site by a licensed technician, with running pressures checked on gauges and a leak check performed. It also requires function setting F3-40 to fully reset.

Sources

Fujitsu mini-split code J2: Branch box error

Soft lockoutShown as: OPERATION lamp blinks 13 times, TIMER lamp blinks 2 times, ECONOMY lamp blinking continuously

Branch box error. The branch box has stopped communicating with the indoor units connected to it.

Manual wording: “Branch Box Error - When the branch box stops communicating with connected indoor units.”

Documented for: Halcyon HFI Flex multi-zone systems with branch boxes (RLF/RLF1 indoor units, RLXFZ outdoor units); AOU48RLXFZ shows EJ2U

Likely causes, most common first

  1. Loose or erroneous molex plug connections in the branch box
  2. Defective or crossed field wiring between the branch box and the indoor units
  3. Branch box lost power
  4. Failed branch box control board

What you can safely check yourself

  • Check that the branch box still has power at its breaker
  • Turn the power off to the outdoor unit and branch boxes for about 5 minutes, then restore power

When to call a technician

Branch box wiring runs at line voltage and every zone lands there. Have the installing contractor trace and correct it.

Source

How old is this Fujitsu?

Age changes what a fault code means for you. The same failure is a routine repair on a six-year-old unit and the end of the line on a twenty-year-old one. Your Fujitsu serial number has the build date in it.

Decode your Fujitsuserial number →

Manuals used for this page