Mini Split Error Codes (Fujitsu, Carrier, Pioneer, Mitsubishi, Samsung, Gree…)

What do mini split error codes mean? Error codes for Mitsubishi, Fujitsu, Carrier, MrCool, etc.?

Fujitsu mini split error codes can be a homeowner’s best friend, pointing to simple fixes that get your system working again. Or, worst case scenario, they can signal a coming nightmare – something significantly wrong.

Here is a comprehensive guide to mini split error codes by brand.

Use the Navigation box to find your brand, what the code means and tips on what to do to resolve the issue.

The information begins with common indoor unit error codes before covering the brands.

Fault Codes – They are the same thing as error codes.

Common Mini Split Error Codes

There are a few error codes which, if not universally used, are quite common.


Indoor / Outdoor Units Communication Error: The components of the system have lost communication with one another due to faulty wiring or a bad PCB board in either unit.

Versions of E1 for communication errors are used by Fujitsu (code 11, E 1 1), Carrier (E1 and ELECTRICAL 01), Pioneer and MrCool (Mr Cool).

Gree error code E1 means too much refrigerant or the heat exchanger is malfunctioning. For Blueridge, error code E1 is a high-pressure refrigerant fault. Mitsubishi E1 error code is a fault in the remote controller. For Daikin error code E1, the problem is a bad circuit board.


Various errors: Error code E3 is used by Carrier, Pioneer, Mitsubishi, Gree and MrCool. The code means something different for each manufacturer. See the lists below for each manufacturer to see what your E3 error code means.


This is used by Daikin to signal a bad heat exchanger temp sensor or thermistor. Samsung has about 20 codes that begin with C4 – C416, C422, C440, etc.


This is an LG mini split error code that signals that the compressor electrical current is high. It can signal bad windings in the compressor.


While error code P4 is common, it means different things to the manufacturers that employ it. Carrier – Compressor fault or compressor temperature protection. Pioneer – Outdoor unit exhaust temperature protection or too high. Mitsubishi P4 error code is a drain issue – the condensate pump isn’t working or the drain is blocked. For Daikin, the P4 error code is a faulty inverter circuit. The MrCool P4 error code signals a fault in the inverter compressor.


This is another error code with different definitions. The Carrier P6 error code signals a bad Intelligent Power Module (IPM). The Pioneer P6 error code signals overheating protection in AC mode. The Mitsubishi P6 error code is for freezing/overheating of the indoor unit. And the MrCool P6 error code is for low refrigerant protection – a possible refrigerant leak. 

Complete Error Codes for Different Brands

Here are mini split error codes for most major brands.

Fujitsu Mini Split Error Codes

You’ll find an easy-to-follow chart for Fujitsu error codes below. But first, here are the most common Fujitsu error codes and what they mean.

Common Fujitsu Error Codes

Tip: Some Fujitsu manuals place a space between numbers; others don’t. For example, error code 53 might also be shown as 5 3.

10: 10 flashes is what this code means. There is no error code 10, but if the lamp is flashing 10 times before pausing,

11 or 1 1: Serial Communication Error – The indoor/outdoor units are not communicating. Causes are a wiring disconnect between components, main outdoor unit PCB board failure, indoor unit PCB board failure or a problem with the branch box (multizone systems). See page 02-16 of the Fujitsu Service Manual for a troubleshooting walk-through.

53 or 5 3: Drainage Error – (5 LED light flashes and 3 Timer light flashes = error code 5 3). The pump might not be working or the drain line could be plugged. See page 02-30 of the Service Manual for troubleshooting guidance.  

97 or 9 7: Outdoor Unit Fan Motor Error – Operation LED 9 flashes is another indicator of Error code 97. Causes are debris around the fan, a fan motor wire short or break, failed motor or failed outdoor unit main PCB board. See page 02-49 of the Service Manual for tips on diagnosing this issue.

A1 or A 1: Compressor Discharge Temperature (too high)

Tip: This Fujitsu Service Manual has a complete Fujitsu mini split troubleshooting guide for each error code.

Complete Fujitsu Mini Split Fault Codes / Error Codes

Fujitsu fault codes are often seen on the Remote Control. However, you might also see an error code on the outdoor unit.

The codes are essentially the same wherever displayed, though they are written slightly differently. This chart shows the codes for each fault or error.

Note that a few of the codes do not show up in both places.

Complete Fujitsu Error Code List

Controller CodeOutdoor Unit Code: E CodesCode Meaning / Code Related to:
N/A1 1 / 1 1.3 / 1 1.4Serial Communication
12 or 1 2N/AWired remote controller communication
15 or 1 51 5 / 1 5.6Check run unfinished
21 or 2 12 1 / 2 1.2Number of wires and pipes
22 or 2 22 2 / 2 2.1Indoor unit capacity exceeds outdoor unit capacity
23 or 2 3N/AConnected combination
24 or 2 42 4 / 2 4.2Number of indoor units
32 or 32N/AIndoor unit model information problem
35 or 3 5N/AManual auto switch fail
41 or 4 1N/AIndoor room thermistor
42 or 4 2N/AIndoor heat exchanger thermistor
N/A5 U.1Indoor unit error
51 or 5 1N/AIndoor unit fan motor
53 or 5 3N/ADrainage – Drain Pump
57 or 5 7N/ADamper
58 or 5 8N/AIntake grille
62 or 6 26 2 / 6 2.1Outdoor unit information
N/A6 3 / 6 3.1Inverter error
N/A6 4 / 6 4.1A.F. voltage
6A or 6 A6 A / 6 A.1Display PCB communication
71 or 7 17 1 / 7 1.1Discharge thermistor
72 or 7 27 2 / 7 2.1Compressor thermistor
73 or 7 37 3 / 7 3.3Heat exchanger liquid outlet thermistor
74 or 7 47 4 / 7 4.1Outdoor thermistor
75 or 7 57 5 / 7 5.1Suction gas thermistor
77 or 7 77 7 / 7 7.1Heat sink thermistor
82 or 8 28 2 / 8 2.1/8 2.2Sub-cool heat exchanger inlet/outlet thermistor
83 or 8 38 3 / 8 3.1Liquid pipe thermistor
84 or 8 48 4 / 8 4.1Current sensor
86 or 8 68 6 / 8 6.1, 8 6.4, 8 6.4Discharge/Suction/High Pressure
94 or 9 49 4 / 9 4.1Over current sensor
95 or 9 59 5 / 9 5.1Compressor control
97 or 9 79 7 / 9 7.3Outdoor unit fan
99 or 9 99 9 / 9 9.14 way valve
A1 or A 1A 1 / A 1.1EC 54 / F3
A3 or A 3A 3 / A 3.1Compressor temperature
A5 or A 5A 5 / A 5.1Low pressure
J2 or J 2J 2 / J 2.UBranch Box

Tip: When in doubt, search online for the Service Manual for the Fujitsu model number of your indoor unit or outdoor unit, whichever is giving you the error code. It is the Service Manual, not the Operation Manual, that has a list of Fujitsu error codes.

Do the Blinks Mean Anything? Yes. Yes they do. 

The Operation LED and the Timer LED blink out error codes. And the number of blinks correspond to the error codes in the charts. 

For example, if the Operation LED blinks once and then the Timer LED blinks once, that is error code 1 1 or 11, a Serial Communication Error. Here are a few other examples to give you a better idea of how this works. 

Fujitsu Error Code Timer LED

The Economy LED, if your unit has one, will blink continuously regardless of the error. 

*Fujitsu blink codes have been included as an example. Many brands use a similar format. 

Carrier Mini Split Error Codes

There are two very commonly searched Carrier mini split error codes. After defining those codes, a complete list is included.

E1: Indoor/Outdoor Unit Communication Error (aka Serial Communication Error) – These errors are caused by wiring issues or a bad PCB control board in one or the other units.

E4: Indoor Room Temperature Sensor open circuit or shortcircuit – You’ll get this code when the system is in normal Defrost mode. However, if it persists, it shows that you likely have a bad temperature sensor which is causing the system to get stuck in Defrost mode.

Complete Carrier Mini Split Error Codes List

The list shows Flashes in the first column, if applicable. This is the number of times the Operation Lamp/LED flashes to signal this code.

Carrier Mini Split Error Codes

FlashesIndoor Unit Error CodeCode Meaning / Code Related to:
1EH 0 / EH 0A / E0Indoor EEPROM Microcontroller memory
2EL 01 / E1Indoor/Outdoor units not communicating
3EH 02Zero-crossing signal detection
4EH 03 / E3Indoor fan operating outside normal range
5EC 51Outdoor EEPROM
5EC 52 / F2T3 Condenser coil sensor open or short-circuited
5EC 53 / F1T4 Bad ambient air temperature sensor
5EC 54TP or T5 Bad compressor discharge temperature sensor
5EC 56 / E5T2B Bad compressor coil sensor
6EH 60 / E4T1 Bad indoor room temperature sensor
6EH 61T2 Bad compressor coil sensor (see EC56)
12EC 07Outdoor fan operation outside normal range
9EH OBIndoor PCB communication
8EL OC / ECRefrigerant leak detection
7PC 00 / P0IPM malfunction or IGBT OSCP – Over current fault
2PC 01 / P1High pressure protection
3PC 02 / P2Compressor or IPM high temperature/pressure protection
5PC 04 / P4Inverter compressor drive fault
1PC 08Current overload protection
6PC 40Communication fault between outdoor chips
7PC 03Low-pressure (refrigerant) protection
1P5Indoor unit mode conflict
9EH B1 (or EH b1)Indoor board communication fault
11FH OdIonizer malfunction
Outdoor Unit Error CodeCode Meaning / Code Related to:
E0Outdoor EEPROM Fault
E2Indoor/Outdoor unit communication
E3IPM board / outdoor board communication
E4Bad outdoor unit temp sensor
E5Voltage protection
E8Outdoor fan speed
F1No “A” indoor unit coil outlet temp sensor – or bad sensor
F2No “B” indoor unit coil outlet temp sensor – or bad sensor
F3No “C” indoor unit coil outlet temp sensor – or bad sensor
F4No “D” indoor unit coil outlet temp sensor – or bad sensor
F5No “E” indoor unit coil outlet temp sensor – or bad sensor
P1High pressure protection
P2Low pressure protection
P3Compressor current protection
P4Compressor temp protection
P5Condenser high-temp protection
P6IPM module protection

Pioneer Mini Split Error Codes

There are three very common Pioneer mini split error codes. A full list of all Pioneer fault codes follows.

E1: Bad room sensor temperature (infrared room temperature or IRT sensor).

P4: Exhaust overtemperature protection

P1: Over or undervoltage protection

Complete Pioneer Mini Split Error Codes List

You’ll notice that there are alternate (Alt.) codes for a few of the codes. 

Error CodeCode Meaning / Code Related to:
E0Indoor/outdoor unit not communicating
Alt. E0Indoor unit EEPROM fault
ECOutdoor communication fault
Alt. ECRefrigerant leak detection
E1Bad room temperature sensor
Alt. E1Indoor/Outdoor unit not communicating
E2Bad indoor coil temperature sensor
Alt. E2Indoor pipe/coil temperature sensor
E3Bad outdoor coil temperature sensor
Alt. E3Outdoor pipe/coil temperature sensor
E4General system fault
E5Configuration fault
E6Indoor fan motor
E7Bad outdoor temperature sensor
E8Bad exhaust temperature sensor
E9Power module fault
EFBad outdoor fan module
EACurrent sensor fault
EPBad temperature switch
EUBad voltage sensor
EHBad intake temperature sensor
F1Bad outdoor temperature sensor T4
F2Bad coil temperature sensor T3
F3Bad compressor temperature sensor
F4Outdoor unit EEPROM fault
P1Protection from over or undervoltage
P2Overcurrent protection
Alt. P2High temperature protection – compressor
P4Exhaust temperature protection
Alt. P4Inverter compressor drive fault
P6Overheating protection – AC Mode
P7Overheating protection Heating Mode
P8Outdoor overtemperature/undertemperature protection
P9Software control – drive protection
P0Hardware control – module protection

Mitsubishi Mini Split Error Codes

Mitsubishi makes it a little difficult by having separate lists of error codes for each Series. But we’ll start with a few common Mitsubishi error codes.

P5: High condensate level: The condensate pump isn’t working or the drain is blocked.

P6: Freezing/Overheating of indoor unit caused by poor airflow – dirty filter, blockage, bad fan motor.

P8: Abnormal pipe or heat exchanger temperature – caused by refrigerant leak or system not properly sized.

E6 (And E7): Indoor/Outdoor units communication error usually caused by the outdoor unit being powered first. Check whether the drain pump is wired into S1 and S2 – this will cause issues.

Complete Mitsubishi Error Codes List

Error CodeCode Meaning / Code Related to:
EOSystem transmission / remote / communication fault
E0, E1, E2, E3, E4, E5Remote controller issues
E6, E7, E8, E9Indoor/outdoor units not communicating
P1TH1 – Thermistor 1 – Return air thermistor
P2TH2 – Thermistor 2 – Coil/pipe thermistor
P3System communication fault
P4Drain sensor
P5High condensate – drain issues
P6Freezing/Overheating of indoor unit
P7System error – Turn system off and back on
P8Abnormal pipe temperature
P9TH5 Condenser/evaporator thermistor fault
U1High pressure trip – Outside unit blockages
U2High discharge temperature – Overheating outdoor unit
U3Discharge thermistor fault
U4Outdoor thermistor fault
U5TH8/Thermistor 8 – Inverter sink temperature too high
U6Compressor over current protection
U7Low discharge superheat – Outdoor unit
E6, E7Indoor/outdoor units not communicating

Samsung Mini Split Error Codes

Two Samsung error codes are searched more often than others, C4 and C5. Samsung C4 and C5 error codes are not currently in use on any system being sold – or recently retired systems either.

However, there are a series of error codes that begin with C4 and C5. See the Samsung Error Code Lists below for those codes.

Samsung mini split error codes are found in the Service Manual that should have been included with the documents you received. The manuals can also be found online at

Complete Samsung Error Codes List

Important Code Notes: All codes in the list might also begin with “E” depending on the series you have – E101, E102, etc. Unique E codes are at the bottom of the list. In other words, there is no comparable “C” code.

Secondly, if the code appears on the indoor remote controller, it might not show any letter in front of the code: “101” for example instead of “C101.” 

Note – Samsung also uses Yellow, Green and Red lights to show errors on the outdoor units. The Service Manual will show what each means – like these examples.

Samsung Error Codes outdoor
Samsung Error Codes outdoor

Gree Mini Split Error Codes

There are a few common Gree error codes, which are discussed first. The discussion is followed by the complete Gree fault codes list (error codes list).

E1: High pressure protection of the system. During Cooling or Dry modes, all operations cease except the indoor fan. In Heat Mode, all operations cease. Causes include too much refrigerant (superabundant), poor heat exchange caused by blockage, and ambient temperature is too high to allow for heat dispersal.

E6: Communication malfunction. During cooling, the compressor stops but the indoor fan runs. In heat mode, all functions stop. Check to see that the connection wire and built-in wiring of indoor units and outdoor units are connected and in good condition.

If wiring is OK, then the indoor main board or communication circuit of the outdoor board could be bad.  

Here is Gree’s troubleshooting walk-through on the E6 code:

Gree’s troubleshooting walk-through on the E6 code

E7: Mode Conflict – Multizone systems only. This means that either the indoor units and outdoor units are set to different modes or that not all the indoor units are in the same mode.

Gree Error Codes Lists are found in the Service Manuals for each series – Livo, Vireo, etc.

You can also use the Gree Error Code Tool. Enter the code, and Gree will tell you what it means.

Gree also provides a series of error code troubleshooting videos.

Complete Gree Error Codes List

Error CodeCode Meaning / Code Related to…
C5Jumper cap malfunction protection
EELoading EEPROM malfunction
EUFrequency limiting module temp
E1High pressure protection
E2Anti-freezing protection
E3Low refrigerant pressure
E4Compressor exhaust temp too high
E5AC over-current protection
E6Communication failure indoor/outdoor units
E8/H4Anti-high temp protection
FoGathering refrigerant (recovery)
F1Indoor ambient sensor open/short-circuit
F2Indoor tube sensor or evaporator sensor open/short-circuit
F3Outdoor ambient sensor open/short-circuit
F4Outdoor tube sensor open/short-circuit
F5Exhaust /outdoor discharge sensor
F6Overload limit
F8Over current limit
F9High exhaust temp limit
F0Refrigerant leak protection
FHAnti-freezing limit
HCPFC protection
H3Compressor overload protection
H5/P5IPM protection/Module temp too high
H6Indoor fan motor not giving feedback
JFDetection plate malfunction
LPIncompatible indoor/outdoor units
LUFrequency limiting power
L3Outdoor DC fan malfunction
L9Power protection
PHHigh PN voltage protection
PLLow PN voltage protection
PUCapacitor charging malfunction
P7Temp sensor module malfunction
P8High temperature protection module
UL4-way valve reversal abnormal

Blueridge Mini Split Error Codes

Blueridge ductless is the house brand for Alpine Air.

Here are the most common Blueridge error codes followed by the complete list.

E1: High pressure protection. When you see this code, the unit might have too much refrigerant – or the code will be temporary because the pressure is too high at the moment for safe operation.

P4: Inverter compressor drive error. Possible causes are a wiring mistake, bad IPM (intelligent power module) board, bad outdoor unit fan assembly or a bad outdoor PCB control board.

P6: Low pressure protection. The system won’t start while it is gathering refrigerant. If the error code doesn’t turn off, the system might be low on refrigerant. Potential causes are wiring issues, bad outdoor unit fan motor, faulty PCB board or connection problems.

Complete List of Blueridge Mini Split Error Codes

Error CodeCode Meaning – Code related to…
C5Indoor configuration jumper missing on control board
LPIndoor/outdoor units are not compatible
PLLow voltage
E1High pressure protection
E5High current protection/voltage range too large
E6Communication error – possible wiring error
E7Mode conflict in multizone systems
F0Low refrigerant / possible leak
F1Indoor air temp – bad connection or sensor
F2Indoor coil temp – bad connection or sensor
F3Outdoor air temp sensor – bad connection or sensor
F4Outdoor coil temp – bad connection or sensor
F5Compressor discharge temp – bad connection or sensor
H1Defrosting – Not an error
H3Compressor overload protection – Low refrigerant or blockage
H4Restart required
H5IPM module protection – temp too high
H6Indoor fan malfunction
H7Compressor synch: high pressure, low voltage, bad connection
U74-way valve malfunction
U8Restart required

Daikin Mini Split Error Codes

The most common Daikin error codes are U4 and U7. A complete list is found below.

U4: Malfunction of transmission between indoor unit and outdoor unit – They are not communicating. Daikin troubleshooting suggests these common reasons: Wiring short circuit or F1/F2 faulty wiring, defective indoor unit or outdoor unit PCB or system address does not match.

E7: Malfunction of outdoor unit fan motor system – The fan might not rotate due to a debris blockage. Or the wiring harness might not be connected to the PCB or could be defective, if it is connected.

Daikin has an Error Code Search page too.

Complete Daikin Error Code List

Error CodeCode Meaning – Error related to…
0 or 00Normal
UAIndoor/outdoor unit combination doesn’t match
U0Low refrigerant
U2Drop voltage / main circuit overvoltage
U4Indoor/outdoor unit communication/transmission fault
U7Signal transmission error outdoor unit PCB
A1Indoor PCB defective
A5High pressure control / freeze-up protection
A6Fan motor
C4Bad heat exchanger temp sensor or thermistor
C9Faulty suction air temp sensor or room temp thermistor
EACool/Heat mode switching error
E1Circuit board
E5OL activation – compressor overload
E6Compressor startup fault
E7DC fan motor fault
E8Input overcurrent detection
F3High temp discharge pipe control
F6AC mode high pressure control
H0Bad sensor
H6Operation halt – faulty position detection sensor
H8Bad DC current sensor
H9Bad suction air temp sensor
J3Bad discharge pipe temp sensor
J6Bad heat exchanger temp sensor
L3Electrical parts overheat
L4High temperature at inverter circuit heatsink
L5Output overcurrent
P4Faulty inverter circuit – Heatsink temperature sensor

Mr Cool Mini Split Error Codes / MrCool Error Codes

MrCool is the leading DIY brand, but it makes pro-installed units too.

Common error codes are covered first followed by the complete Mr Cool error codes list.

DF: This code means the system is in Defrost Mode, which is a normal function of a mini split. However, if the code remains on and the system doesn’t work, you likely have a bad sensor that is “telling” the system to remain in Defrost.

E1: Actuation of the high pressure switch. This is a normal code – seen when the system is working as it should. However, if it stays on and the system won’t operate, it probably means the system is overcharged with refrigerant.

P6: Low pressure protection – 36,000 BTU units only. This fault code means that the compressor does not have enough refrigerant to start. The code might go away. If it doesn’t, the system is undercharged and might have a refrigerant leak.

Complete MrCool Error Codes List

Error CodeCode Meaning – Error related to…
E0Indoor unit EEPROM parameter fault
E1Indoor/outdoor units not communicating
E2Zero-crossing signal detection
E3Indoor fan speed control
E4Bad indoor room temp sensor T1
E5Bad T2 evaporator coil sensor
ECRefrigerant leak
F0Overload current protection
F1Bad T4 outdoor ambient temperature sensor
F2Bad T3 condenser coil sensor
F3Bad TP compressor discharge temperature sensor
F4Outdoor unit EEPROM parameter fault
F5Outdoor fan speed control
P0IPM malfunction or IGBT over-strong current protection
P1Over voltage or over low voltage protection
P2High temperature protection of IPM module or compressor
P3Outdoor ambient temperature too low for safe operation
P4Inverter compressor drive
P5Multizone systems – Indoor units in different modes
P6Low pressure protection

Written by

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree and EPA & R-410A Certifications.
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