Error-code hub

Daikin error codes

Daikin uses a two-character code shown on the indoor unit or wired controller, and the first character tells you which subsystem is complaining - A- and C- codes are indoor-side, E- through H- are outdoor, and U- codes are communication or power. Knowing that narrows a fault before you read anything else. The 54 codes below cover the ATMOSPHERA, AURORA, OTERRA and ENTRA lines.

See Daikinmini-splits ->Common First Status Displays Error Codes

Status displays: 7
Error codes: 54

Unit applicability

Match your unit before reading the table

This table is sourced for AURORA R-32. If your unit is a different generation or product line not named here, the same display code may vary by generation.

AURORA R-325 models

Common codes first

Most broadly applicable documented codes

Ranking basis: we do not have failure-frequency telemetry. These are ordered by breadth of affected systems in the SplitAtlas catalog - the documented product line's published model count, whether the same code appears on more than one product line, and any manual applicability notes we hold. This is a breadth ranking, not a popularity claim.

A1 means the indoor control board did not pass its internal check. The unit may still power up, but the indoor controls are not trustworthy enough to run normally.

AdvisoryTechnician

Breadth evidence: 5 published catalog models on its documented product line. Manual applicability notes: Daikin current US residential R-32 ductless single-zone systems, including AURORA R-32, ATMOSPHERA R-32, Entra R32, OTERRA R-32, and Nineteen-series style high-wall diagnostics where the same Daikin A/C/E/F/H/J/L/P/U code family is used.; Daikin concealed-duct/FDMQ indoor units where the Nineteen service manual explicitly lists the same indoor drain, fan PCB, remote-controller, and FDMQ-only C/U codes.; Daikin AURORA Multi R-32 and Standard Multi R-32 MXT/MXTH/MXM systems where the MXM engineering manual lists the same homeowner code table.; MXM/MXT/MXTH multi-zone systems for the additional multi-zone U-series and inverter/control codes specifically called out from the MXM manual.
Safe first check: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.

View the fix

A3 means the indoor unit thinks condensate water is not being removed normally or the drain level circuit cannot be trusted. Treat visible water seriously.

AdvisoryTechnician

Breadth evidence: 5 published catalog models on its documented product line. Manual applicability notes: Daikin current US residential R-32 ductless single-zone systems, including AURORA R-32, ATMOSPHERA R-32, Entra R32, OTERRA R-32, and Nineteen-series style high-wall diagnostics where the same Daikin A/C/E/F/H/J/L/P/U code family is used.; Daikin concealed-duct/FDMQ indoor units where the Nineteen service manual explicitly lists the same indoor drain, fan PCB, remote-controller, and FDMQ-only C/U codes.; Daikin AURORA Multi R-32 and Standard Multi R-32 MXT/MXTH/MXM systems where the MXM engineering manual lists the same homeowner code table.; MXM/MXT/MXTH multi-zone systems for the additional multi-zone U-series and inverter/control codes specifically called out from the MXM manual.
Safe first check: Turn the unit off if you see water at the indoor unit. Check only for an obvious blocked drain outlet or kinked external drain hose; do not open the cabinet. If water is present or A3 remains, leave it off.

View the fix

A5 means the indoor coil is getting too cold in cooling or the system is limiting heating/high-pressure operation. Dirty filters and blocked airflow are common homeowner-side contributors.

AdvisoryDIY part

Breadth evidence: 5 published catalog models on its documented product line. Manual applicability notes: Daikin current US residential R-32 ductless single-zone systems, including AURORA R-32, ATMOSPHERA R-32, Entra R32, OTERRA R-32, and Nineteen-series style high-wall diagnostics where the same Daikin A/C/E/F/H/J/L/P/U code family is used.; Daikin concealed-duct/FDMQ indoor units where the Nineteen service manual explicitly lists the same indoor drain, fan PCB, remote-controller, and FDMQ-only C/U codes.; Daikin AURORA Multi R-32 and Standard Multi R-32 MXT/MXTH/MXM systems where the MXM engineering manual lists the same homeowner code table.; MXM/MXT/MXTH multi-zone systems for the additional multi-zone U-series and inverter/control codes specifically called out from the MXM manual.
Safe first check: Turn the unit off, clean the washable indoor filter, and make sure the return and supply air paths are open. If the filter is missing or damaged, replace only the user-removable air filter after verifying the indoor model. Restart once after the coil has time to normalize.

Sourced homeowner part

Daikin titanium apatite deodorizing filter without frame

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View the fix

A6 means the indoor blower motor is not operating or reporting normally. Filters are safe to check, but the motor, feedback wiring, and board are technician work.

AdvisoryTechnician

Breadth evidence: 5 published catalog models on its documented product line. Manual applicability notes: Daikin current US residential R-32 ductless single-zone systems, including AURORA R-32, ATMOSPHERA R-32, Entra R32, OTERRA R-32, and Nineteen-series style high-wall diagnostics where the same Daikin A/C/E/F/H/J/L/P/U code family is used.; Daikin concealed-duct/FDMQ indoor units where the Nineteen service manual explicitly lists the same indoor drain, fan PCB, remote-controller, and FDMQ-only C/U codes.; Daikin AURORA Multi R-32 and Standard Multi R-32 MXT/MXTH/MXM systems where the MXM engineering manual lists the same homeowner code table.; MXM/MXT/MXTH multi-zone systems for the additional multi-zone U-series and inverter/control codes specifically called out from the MXM manual.
Safe first check: Turn the unit off, clean the indoor filter, and check only for visible blockage at the return or outlet. Restart once; if the blower is noisy, stuck, or A6 returns, stop troubleshooting.

View the fix

A8 points to the indoor fan control board path on applicable ducted/FDMQ equipment. It is not a remote setting or user-replaceable part.

AdvisoryTechnician

Breadth evidence: 5 published catalog models on its documented product line. Manual applicability notes: Daikin current US residential R-32 ductless single-zone systems, including AURORA R-32, ATMOSPHERA R-32, Entra R32, OTERRA R-32, and Nineteen-series style high-wall diagnostics where the same Daikin A/C/E/F/H/J/L/P/U code family is used.; Daikin concealed-duct/FDMQ indoor units where the Nineteen service manual explicitly lists the same indoor drain, fan PCB, remote-controller, and FDMQ-only C/U codes.; Daikin AURORA Multi R-32 and Standard Multi R-32 MXT/MXTH/MXM systems where the MXM engineering manual lists the same homeowner code table.; MXM/MXT/MXTH multi-zone systems for the additional multi-zone U-series and inverter/control codes specifically called out from the MXM manual.
Safe first check: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.

View the fix

AF is an indoor accessory/drain-related abnormality on models that use that function. For a homeowner, the main concern is water or a failed accessory circuit.

AdvisoryTechnician

Breadth evidence: 5 published catalog models on its documented product line. Manual applicability notes: Daikin current US residential R-32 ductless single-zone systems, including AURORA R-32, ATMOSPHERA R-32, Entra R32, OTERRA R-32, and Nineteen-series style high-wall diagnostics where the same Daikin A/C/E/F/H/J/L/P/U code family is used.; Daikin concealed-duct/FDMQ indoor units where the Nineteen service manual explicitly lists the same indoor drain, fan PCB, remote-controller, and FDMQ-only C/U codes.; Daikin AURORA Multi R-32 and Standard Multi R-32 MXT/MXTH/MXM systems where the MXM engineering manual lists the same homeowner code table.; MXM/MXT/MXTH multi-zone systems for the additional multi-zone U-series and inverter/control codes specifically called out from the MXM manual.
Safe first check: Turn the unit off if water is present. Check only for an obvious blocked external drain outlet; do not open panels or bypass any float switch.

View the fix

Safe first checks

Checks you can do without opening the unit

These codes have homeowner-safe steps such as filters, airflow, condensate/drain checks, remote/controller items, or a single safe power reset. If the code returns, stop at the boundary in the card.

A5DIY part

Turn the unit off, clean the washable indoor filter, and make sure the return and supply air paths are open. If the filter is missing or damaged, replace only the user-removable air filter after verifying the indoor model. Restart once after the coil has time to normalize.

Sourced homeowner part

Daikin titanium apatite deodorizing filter without frame

View sourced part route

Read the full code guide

A1Technician

Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.

Read the full code guide

A3Technician

Turn the unit off if you see water at the indoor unit. Check only for an obvious blocked drain outlet or kinked external drain hose; do not open the cabinet. If water is present or A3 remains, leave it off.

Read the full code guide

A6Technician

Turn the unit off, clean the indoor filter, and check only for visible blockage at the return or outlet. Restart once; if the blower is noisy, stuck, or A6 returns, stop troubleshooting.

Read the full code guide

Daikin mini-splits

Use the Daikin catalog to connect these manual error codes to current model pages and replacement options.

See Daikinmini-splits ->

Daikin AURORA 9,000 BTU R-32 208/230V (FTXV09AVJU9 / RXT09AVJU9)
AURORA R-32
Daikin AURORA 12,000 BTU R-32 208/230V (FTXV12AVJU9 / RXT12AVJU9)
AURORA R-32
Daikin AURORA 15,000 BTU R-32 208/230V (FTXV15AVJU9 / RXT15AVJU9)
AURORA R-32
Daikin AURORA 18,000 BTU R-32 208/230V (FTXV18AVJU9 / RXT18AVJU9)
AURORA R-32
Daikin AURORA 24,000 BTU R-32 208/230V (FTXV24AVJU9 / RXT24AVJU9)
AURORA R-32
Daikin ATMOSPHERA 9,000 BTU R-32 208/230V (FTXM09WVJU9 / RXM09WVJU9)
ATMOSPHERA R-32

Status displays

00

00 means the remote-controller code check did not find an active matching Daikin malfunction code. It is a normal/no-fault result, not a repair code.

Not an error

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: No repair action is needed if the system is heating or cooling normally. If comfort is poor, keep checking for the actual blinking or displayed code.
Status note: This is a normal status indication, not an error, unless comfort is poor, water is present, or the indication never clears.

View the fix ->

3-MINUTE STANDBY

Daikin controls can wait about 3 minutes before restarting the compressor after a stop, mode change, or power interruption. That delay protects the compressor and is not a malfunction.

Not an error

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Wait several minutes without repeatedly pressing buttons or cycling the breaker. Operation should resume when the protection timer finishes.
Status note: This is a normal status indication, not an error, unless comfort is poor, water is present, or the indication never clears.

View the fix ->

CHECKING CONNECTION

A Daikin wired controller can show a connection-check message during startup. The MXM manual says this can be normal for up to about 180 seconds after power is applied.

Not an error

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Wait up to 3 minutes after power is restored. If the message clears and normal operation returns, no repair is needed.
Status note: This is a normal status indication, not an error, unless comfort is poor, water is present, or the indication never clears.

View the fix ->

DEFROST

Defrost is a normal heating-cycle status. The indoor fan may pause, the outdoor unit may steam, and warm air should resume after the cycle finishes.

Not an error

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Let defrost finish. Keep the outdoor unit clear of snow buildup around the base, but do not chip ice from the coil.
Status note: This is a normal status indication, not an error, unless comfort is poor, water is present, or the indication never clears.

View the fix ->

FIELD SETTING

Field-setting, inspection, and test-run screens are service/setup displays. They are not homeowner error codes by themselves.

Not an error

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Exit the service or field-setting screen if it was opened accidentally. Do not change field settings unless the installing contractor instructed you.
Status note: This is a normal status indication, not an error, unless comfort is poor, water is present, or the indication never clears.

View the fix ->

FILTER CLEANING SIGN

The filter cleaning sign is a reminder to clean the user-removable indoor filter. It is not the same thing as a sensor or board fault.

Not an error

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the unit off, clean and dry the washable filter, reinstall it fully, then reset the reminder according to the controller instructions.
Status note: This is a normal status indication, not an error, unless comfort is poor, water is present, or the indication never clears.

View the fix ->

MODE CONFLICT

On a Daikin multi-zone system, one indoor head asking for heat while another asks for cooling can make the non-priority unit enter standby. That is a coordination status, not a failed part.

Not an error

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Set all connected indoor heads to the same mode, then wait several minutes. Expected result: the conflict clears and non-priority rooms resume.
Status note: This is a normal status indication, not an error, unless comfort is poor, water is present, or the indication never clears.

View the fix ->

All error codes

U0

U0 means the system is seeing signs of refrigerant shortage or pressure drop. On current Daikin R-32 systems, treat that as a possible refrigerant leak until a licensed technician proves otherwise.

Stop useTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Stop heating and cooling, ventilate the room, avoid flames, sparks, and smoking, and do not keep resetting the system. Expected result: the system remains off until a licensed technician verifies the refrigerant circuit and space safety.
When to call a pro: Call a licensed HVAC technician before normal operation. Tell them the display is Daikin U0 and the system uses R-32 A2L refrigerant.

View the fix ->

A1

A1 means the indoor control board did not pass its internal check. The unit may still power up, but the indoor controls are not trustworthy enough to run normally.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if A1 returns after one reset or appeared after service. Tell them the code points to the indoor PCB.

View the fix ->

A3

A3 means the indoor unit thinks condensate water is not being removed normally or the drain level circuit cannot be trusted. Treat visible water seriously.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the unit off if you see water at the indoor unit. Check only for an obvious blocked drain outlet or kinked external drain hose; do not open the cabinet. If water is present or A3 remains, leave it off.
When to call a pro: Call a licensed HVAC technician if water is present, the indoor head drips, or A3 returns. Tell them the code is Daikin drain level control.

View the fix ->

A5

A5 means the indoor coil is getting too cold in cooling or the system is limiting heating/high-pressure operation. Dirty filters and blocked airflow are common homeowner-side contributors.

AdvisoryDIY part

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the unit off, clean the washable indoor filter, and make sure the return and supply air paths are open. If the filter is missing or damaged, replace only the user-removable air filter after verifying the indoor model. Restart once after the coil has time to normalize.
When to call a pro: Call a licensed HVAC technician if A5 returns after filter and airflow checks, if ice is visible, or if heating/cooling remains weak. Tell them the code is freeze-up or peak-cut/high-pressure control.

Sourced homeowner part

Daikin titanium apatite deodorizing filter without frame

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View the fix ->

A6

A6 means the indoor blower motor is not operating or reporting normally. Filters are safe to check, but the motor, feedback wiring, and board are technician work.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the unit off, clean the indoor filter, and check only for visible blockage at the return or outlet. Restart once; if the blower is noisy, stuck, or A6 returns, stop troubleshooting.
When to call a pro: Call a licensed HVAC technician if A6 returns or the indoor blower does not run normally. Tell them the code is indoor fan motor related.

View the fix ->

A8

A8 points to the indoor fan control board path on applicable ducted/FDMQ equipment. It is not a remote setting or user-replaceable part.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if A8 returns. Tell them the manual identifies the indoor fan PCB.

View the fix ->

AF

AF is an indoor accessory/drain-related abnormality on models that use that function. For a homeowner, the main concern is water or a failed accessory circuit.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the unit off if water is present. Check only for an obvious blocked external drain outlet; do not open panels or bypass any float switch.
When to call a pro: Call a licensed HVAC technician if AF returns, water is present, or the indoor unit uses a drain pump or humidifier accessory. Tell them the code is AF humidifier/drain related.

View the fix ->

C4

C4 means the indoor coil temperature reading is missing, shorted, or not believable. The unit may stop because it cannot protect the coil without that sensor input.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if C4 returns. Tell them the code points to the indoor heat exchanger thermistor circuit.

View the fix ->

C5

C5 is an indoor thermistor-related code used on applicable indoor or BEV configurations. It is a sensor circuit diagnosis, not a user setting.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if C5 returns. Tell them the MXM/Nineteen tables identify an indoor piping thermistor circuit.

View the fix ->

C9

C9 means the indoor unit is not getting a believable room-air temperature reading. That can make comfort poor or stop operation because the unit cannot judge the room correctly.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if C9 returns. Tell them the code points to the room/suction air thermistor.

View the fix ->

CC

CC means a humidity sensor input is not being read normally. This affects comfort/control logic on models with humidity sensing, but it is not a homeowner-replaceable part.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if CC returns. Tell them the Atmosphera/MXM table identifies a humidity sensor fault.

View the fix ->

CJ

CJ means the temperature sensor in a wired/remote controller is not being read normally on systems that use that input.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Reset power once if you can do so safely and make sure the controller is not in direct sun, over a heat source, or blocked by furniture. If CJ returns, stop there.
When to call a pro: Call a licensed HVAC technician if CJ returns. Tell them the code is remote controller thermistor abnormality.

Technician part context

Daikin wired remote controller

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View the fix ->

E1

E1 means the outdoor control board or an outdoor board-controlled circuit is not operating normally. It is outside the homeowner-safe service area.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if E1 returns. Tell them the code is outdoor PCB abnormality.

View the fix ->

E3

E3 means the high-pressure switch opened or the system detected that circuit abnormally. Airflow can contribute, but pressure-switch diagnosis is professional work.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the unit off, clean indoor filters, and clear only loose debris around the outdoor unit. Restart once. Do not attach gauges, adjust valves, or add refrigerant.
When to call a pro: Call a licensed HVAC technician if E3 returns. Tell them the code is high-pressure switch actuation.

View the fix ->

E5

E5 means the compressor has overloaded or, on some models, the high-pressure switch is involved. Repeated E5 can protect expensive outdoor components.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off, clean the washable indoor filters, open blocked supply/return paths, and clear only loose leaves, snow, or debris around the outdoor unit without removing panels. Restore power once; if the code returns, stop there.
When to call a pro: Call a licensed HVAC technician if E5 returns after airflow is corrected. Tell them the code is compressor overload/HPS activation.

View the fix ->

E6

E6 means the outdoor unit could not start or keep the compressor rotating as expected. Do not keep forcing restarts.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off for several minutes and reset once if safe. If E6 returns, leave the unit off and do not keep trying to start the compressor.
When to call a pro: Call a licensed HVAC technician if E6 returns or the outdoor unit clicks/hums without starting. Tell them the code is compressor lock/startup abnormality.

View the fix ->

E7

E7 means the outdoor fan is stopped, locked, or not reporting normally. A visible obstruction may be safe to remove from outside the grille, but motor/board diagnosis is professional work.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the unit off before looking at the outdoor fan. Remove only loose debris outside the grille, restore power once, and stop if the fan still will not run or E7 returns.
When to call a pro: Call a licensed HVAC technician if E7 returns, the blade is damaged, or the fan is not visibly blocked. Tell them the code is outdoor DC fan lock/fault.

View the fix ->

E8

E8 means the outdoor unit detected AC input current outside the allowed range. This is an electrical/protection code, not a homeowner repair.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off and note whether lights dimmed, storms occurred, generator power was used, or other circuits had trouble. Reset once only after power is stable. If the code returns or a breaker trips, leave the system off.
When to call a pro: Call a licensed HVAC technician or electrician if E8 returns or any breaker trips. Tell them the code is input overcurrent detection.

View the fix ->

E9

E9 means the outdoor electronic expansion valve coil or its driver circuit is not operating normally. That valve meters refrigerant and is not homeowner-serviceable.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if E9 returns. Tell them the MXM table identifies the outdoor electronic expansion valve coil.

View the fix ->

EA

EA means the heat pump did not confirm normal reversing-valve/cooling-heating switching. Symptoms may include poor heat, poor cooling, or room-temperature air.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Set all indoor heads to the same mode, turn the system off, and reset power once. If EA returns or the system will not switch between heat and cool, stop there.
When to call a pro: Call a licensed HVAC technician if EA returns. Tell them the code is four-way valve/cooling-heating switching.

View the fix ->

F3

F3 means the compressor discharge temperature is too high or the unit is limiting operation to protect itself. Airflow problems can contribute, but repeated F3 needs service.

AdvisoryDIY

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off, clean the washable indoor filters, open blocked supply/return paths, and clear only loose leaves, snow, or debris around the outdoor unit without removing panels. Restore power once; if the code returns, stop there.
When to call a pro: Call a licensed HVAC technician if F3 returns after airflow is corrected or cooling/heating is weak. Tell them the code is discharge pipe temperature control.

View the fix ->

F6

F6 means the system limited or stopped cooling because pressure/temperature conditions were too high. The safest homeowner check is airflow.

AdvisoryDIY

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off, clean the washable indoor filters, open blocked supply/return paths, and clear only loose leaves, snow, or debris around the outdoor unit without removing panels. Restore power once; if the code returns, stop there.
When to call a pro: Call a licensed HVAC technician if F6 returns after filters and outdoor clearance are corrected. Tell them the code is high-pressure control in cooling.

View the fix ->

F8

F8 means the compressor got too hot internally or the system thinks it did. Airflow and operating load are safe to check first; repeated F8 is professional diagnosis.

AdvisoryDIY

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off, clean the washable indoor filters, open blocked supply/return paths, and clear only loose leaves, snow, or debris around the outdoor unit without removing panels. Restore power once; if the code returns, stop there.
When to call a pro: Call a licensed HVAC technician if F8 returns after airflow is corrected or the outdoor unit struggles to run. Tell them the code is compressor internal temperature abnormality.

View the fix ->

H0

H0 means an outdoor compressor-system sensor input is abnormal. The unit may stop because it cannot verify compressor conditions.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if H0 returns. Tell them the code is compressor system sensor abnormality.

View the fix ->

H3

H3 means the outdoor high-pressure sensor/switch path is abnormal. Because this protects the refrigerant circuit, do not keep resetting it.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the unit off, clean filters, and clear only loose outdoor debris. Reset once. Do not attach gauges or adjust service valves.
When to call a pro: Call a licensed HVAC technician if H3 returns. Tell them the MXM table lists high-pressure sensor/switch abnormality.

View the fix ->

H6

H6 means the inverter cannot confirm compressor rotor/position feedback normally. This belongs with compressor-drive diagnosis.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off for several minutes and reset once if safe. If H6 returns, leave the unit off and do not keep trying to start it.
When to call a pro: Call a licensed HVAC technician if H6 returns or the outdoor unit will not start. Tell them the code is compressor position sensor abnormality.

View the fix ->

H7

H7 means the fan inverter/power module temperature is abnormal on applicable outdoor units. Homeowner checks stop at outdoor airflow.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the unit off, clear only loose debris around the outdoor unit, and restore power once after it cools. If H7 returns, stop using the unit.
When to call a pro: Call a licensed HVAC technician if H7 returns. Tell them the MXM table lists fan IPM temperature error.

View the fix ->

H8

H8 means the outdoor inverter/power section is not reading voltage or current normally. It is electrical/inverter diagnosis.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off and note whether lights dimmed, storms occurred, generator power was used, or other circuits had trouble. Reset once only after power is stable. If the code returns or a breaker trips, leave the system off.
When to call a pro: Call a licensed HVAC technician if H8 returns. Tell them the code is DC voltage/current sensor abnormality.

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H9

H9 means the outdoor air temperature sensor reading is missing, shorted, or not believable. The system may protect itself because outdoor conditions are unknown.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if H9 returns. Tell them the code is outdoor air thermistor abnormality.

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J3

J3 means the outdoor unit cannot trust the compressor discharge pipe temperature reading. That reading is important for compressor protection.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if J3 returns. Tell them the code is discharge pipe thermistor abnormality.

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J6

J6 means the outdoor coil temperature reading is missing, shorted, or not believable. The unit may lose defrost and pressure-control judgment.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if J6 returns. Tell them the code is outdoor heat exchanger thermistor abnormality.

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J8

J8 means the liquid-pipe temperature reading is not believable on models that use that sensor. This is a refrigerant-circuit sensor diagnosis.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if J8 returns. Tell them the code is liquid pipe thermistor abnormality.

View the fix ->

L0

L0 is a broad outdoor inverter-system fault. It points to compressor-drive electronics, not a homeowner repair.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off for several minutes and reset once if safe. If L0 returns, leave the system off and schedule service.
When to call a pro: Call a licensed HVAC technician if L0 returns. Tell them the MXM table lists outdoor inverter system fault.

View the fix ->

L3

L3 means the outdoor electrical box area got too hot or the unit believes it did. Blocked outdoor airflow and heat buildup are safe homeowner checks.

AdvisoryDIY

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the unit off, clear loose debris around the outdoor unit, and make sure the discharge side has open clearance. Restore power once after it cools. If L3 returns, stop there.
When to call a pro: Call a licensed HVAC technician if L3 returns after outdoor clearance is corrected. Tell them the code is outdoor electrical box temperature rise.

View the fix ->

L4

L4 means the outdoor inverter heat sink/radiation fin temperature is too high or the sensor path suggests it is. Heat and airflow are the safe first checks.

AdvisoryDIY

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the unit off, clear loose debris around the outdoor unit, and let it cool before one reset. Do not remove panels or wash electronics.
When to call a pro: Call a licensed HVAC technician if L4 returns after outdoor clearance is corrected. Tell them the code is inverter heat sink/radiation fin temperature rise.

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L5

L5 means the inverter output current is abnormal. This can protect the power module and compressor, so repeated resets are a bad idea.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off for several minutes and reset once if safe. If L5 returns, leave the system off and do not force repeated starts.
When to call a pro: Call a licensed HVAC technician if L5 returns. Tell them the code is output overcurrent/IPM abnormality.

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L6

L6 means the outdoor unit is detecting a compressor motor ground/short condition. This is an electrical safety and compressor-drive diagnosis.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Leave the system off after one failed reset. Do not open the outdoor cabinet or keep trying to start the compressor.
When to call a pro: Call a licensed HVAC technician if L6 appears. Tell them the MXM table lists compressor motor ground/short circuit.

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L8

L8 means the compressor is overloaded or a compressor motor lead may be disconnected. This is not homeowner-serviceable.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off, clean filters and clear outdoor airflow, then reset once if safe. If L8 returns, leave it off.
When to call a pro: Call a licensed HVAC technician if L8 returns. Tell them the MXM table lists compressor overload or motor wire disconnection.

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L9

L9 means the compressor is not starting or rotating as expected. It overlaps with compressor-start/lock diagnosis and should not be repeatedly reset.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off for several minutes and reset once if safe. If L9 returns, leave the outdoor unit off.
When to call a pro: Call a licensed HVAC technician if L9 returns. Tell them the MXM table lists compressor lock.

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LA

LA means the outdoor power unit/inverter electronics are reporting a fault. It is inside the outdoor cabinet and is technician-only.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off and reset once if safe. If LA returns, leave the unit off and schedule service.
When to call a pro: Call a licensed HVAC technician if LA returns. Tell them the MXM table lists outdoor power unit error.

View the fix ->

LC

LC means the inverter section and outdoor main control are not communicating normally. The outdoor unit may stop because compressor drive commands cannot be trusted.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if LC returns. Tell them the MXM table lists inverter-to-outdoor-control transmission.

View the fix ->

P1

P1 means the outdoor unit detected an abnormal power supply balance or lost phase. Homeowners should not test live equipment.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off and note whether lights dimmed, storms occurred, generator power was used, or other circuits had trouble. Reset once only after power is stable. If the code returns or a breaker trips, leave the system off.
When to call a pro: Call a licensed HVAC technician or electrician if P1 returns or any breaker trips. Tell them the code is power voltage imbalance/phase loss.

View the fix ->

P4

P4 means the outdoor unit cannot trust the inverter heat sink/radiation fin temperature sensor. That sensor protects the power electronics.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if P4 returns. Tell them the code is inverter heat sink/radiation fin thermistor abnormality.

View the fix ->

U1

U1 means the outdoor unit sees an abnormal incoming phase condition. This is electrical service work, not a reset-and-ignore code.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off and note whether lights dimmed, storms occurred, generator power was used, or other circuits had trouble. Reset once only after power is stable. If the code returns or a breaker trips, leave the system off.
When to call a pro: Call a licensed HVAC technician or electrician if U1 returns or any breaker trips. Tell them the code is reversed/lost phase.

View the fix ->

U2

U2 means the outdoor inverter/power circuit saw voltage outside the expected range. It may follow a utility event, but repeated U2 needs electrical and inverter diagnosis.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off and note whether lights dimmed, storms occurred, generator power was used, or other circuits had trouble. Reset once only after power is stable. If the code returns or a breaker trips, leave the system off.
When to call a pro: Call a licensed HVAC technician or electrician if U2 returns, lights dim, or a breaker trips. Tell them the code is Daikin voltage protection.

View the fix ->

U4

U4 means the indoor and outdoor units are not communicating reliably. The system may stop because the two halves of the heat pump cannot coordinate safely.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if U4 returns after one reset, appears on a new install, or more than one indoor head is affected. Tell them it is indoor/outdoor transmission.

View the fix ->

U5

U5 means the wired/controller communication path is not being read normally. It can follow startup or wiring changes, but a repeat code needs service.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: If the display says Checking the connection, wait up to 3 minutes after power-up. Otherwise power cycle once if safe. If U5 returns, stop resetting.
When to call a pro: Call a licensed HVAC technician if U5 returns or the controller will not communicate. Tell them the code is indoor-to-remote-controller transmission.

View the fix ->

U6

U6 is a multi-zone/control communication code. It means indoor units or their control path are not exchanging expected signals.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Set all zones to the same mode and power cycle once if safe. If U6 returns, write down which rooms are affected and stop resetting.
When to call a pro: Call a licensed HVAC technician if U6 returns. Tell them the MXM table lists indoor-unit transmission.

View the fix ->

U7

U7 means the outdoor control boards are not exchanging the expected signal. On single-zone tables it is outdoor PCB transmission; MXM tables also use U7 for outdoor-unit transmission.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off with the remote, then power cycle once at the breaker or disconnect if you can do that safely. Expected result: a temporary control fault clears; if the code returns, stop resetting and schedule service.
When to call a pro: Call a licensed HVAC technician if U7 returns. Tell them the code is outdoor PCB/outdoor-unit transmission.

View the fix ->

U8

U8 means two controllers or a controller pair are not agreeing as main/sub or are not communicating normally.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Do not change installer settings. Power cycle once if safe; if U8 returns, note whether there are two controllers and call for service.
When to call a pro: Call a licensed HVAC technician if U8 returns. Tell them the code is main/sub remote-controller transmission.

View the fix ->

U9

U9 means an indoor, BEV, BS, or outdoor unit within one system is not communicating correctly. It is a multi-zone/control-path diagnosis.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Set every connected indoor unit to the same mode, power cycle once if safe, and note which zone first showed the problem. If U9 returns, stop there.
When to call a pro: Call a licensed HVAC technician if U9 returns. Tell them the MXM table points to transmission within a single system.

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UA

UA means the indoor and outdoor units are not seeing an allowed electrical or equipment combination. It often points to installation, voltage, or pairing mismatch.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off and do not keep testing modes. Record the indoor and outdoor model numbers if accessible without opening panels.
When to call a pro: Call the installing contractor or a licensed HVAC technician before normal operation. Tell them the code is UA combination/voltage abnormality.

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UF

UF is a multi-zone setup/configuration code. It means the system settings, BEV connection, or indoor-unit relationship are not set the way the controls expect.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off and do not swap wires or change field settings. Record which rooms are connected and whether installation or service happened recently.
When to call a pro: Call the installer or a licensed HVAC technician if UF appears. Tell them the MXM table points to unset system or incorrect BEV/indoor settings.

View the fix ->

UH

UH is a broad Daikin system fault in the MXM/control table. It says the system relationship needs diagnosis, but it does not name a homeowner-serviceable part.

AdvisoryTechnician

Sourced Jul 2026

Applies to: AURORA R-32
Homeowner fix: Turn the system off, note all displayed codes and affected rooms, and reset once only if safe. If UH returns, leave the system off until service.
When to call a pro: Call a licensed HVAC technician if UH returns. Tell them the MXM table lists UH as system fault and provide all indoor/outdoor model numbers.

View the fix ->