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.
E1
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.
E3
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.
C4
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.
C6
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.
P4
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.
P6
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 Code | Outdoor Unit Code: E Codes | Code Meaning / Code Related to: |
| N/A | 1 1 / 1 1.3 / 1 1.4 | Serial Communication |
| 12 or 1 2 | N/A | Wired remote controller communication |
| 15 or 1 5 | 1 5 / 1 5.6 | Check run unfinished |
| 21 or 2 1 | 2 1 / 2 1.2 | Number of wires and pipes |
| 22 or 2 2 | 2 2 / 2 2.1 | Indoor unit capacity exceeds outdoor unit capacity |
| 23 or 2 3 | N/A | Connected combination |
| 24 or 2 4 | 2 4 / 2 4.2 | Number of indoor units |
| 32 or 32 | N/A | Indoor unit model information problem |
| 35 or 3 5 | N/A | Manual auto switch fail |
| 41 or 4 1 | N/A | Indoor room thermistor |
| 42 or 4 2 | N/A | Indoor heat exchanger thermistor |
| N/A | 5 U.1 | Indoor unit error |
| 51 or 5 1 | N/A | Indoor unit fan motor |
| 53 or 5 3 | N/A | Drainage – Drain Pump |
| 57 or 5 7 | N/A | Damper |
| 58 or 5 8 | N/A | Intake grille |
| 62 or 6 2 | 6 2 / 6 2.1 | Outdoor unit information |
| N/A | 6 3 / 6 3.1 | Inverter error |
| N/A | 6 4 / 6 4.1 | A.F. voltage |
| 6A or 6 A | 6 A / 6 A.1 | Display PCB communication |
| 71 or 7 1 | 7 1 / 7 1.1 | Discharge thermistor |
| 72 or 7 2 | 7 2 / 7 2.1 | Compressor thermistor |
| 73 or 7 3 | 7 3 / 7 3.3 | Heat exchanger liquid outlet thermistor |
| 74 or 7 4 | 7 4 / 7 4.1 | Outdoor thermistor |
| 75 or 7 5 | 7 5 / 7 5.1 | Suction gas thermistor |
| 77 or 7 7 | 7 7 / 7 7.1 | Heat sink thermistor |
| 82 or 8 2 | 8 2 / 8 2.1/8 2.2 | Sub-cool heat exchanger inlet/outlet thermistor |
| 83 or 8 3 | 8 3 / 8 3.1 | Liquid pipe thermistor |
| 84 or 8 4 | 8 4 / 8 4.1 | Current sensor |
| 86 or 8 6 | 8 6 / 8 6.1, 8 6.4, 8 6.4 | Discharge/Suction/High Pressure |
| 94 or 9 4 | 9 4 / 9 4.1 | Over current sensor |
| 95 or 9 5 | 9 5 / 9 5.1 | Compressor control |
| 97 or 9 7 | 9 7 / 9 7.3 | Outdoor unit fan |
| 99 or 9 9 | 9 9 / 9 9.1 | 4 way valve |
| A1 or A 1 | A 1 / A 1.1 | EC 54 / F3 |
| A3 or A 3 | A 3 / A 3.1 | Compressor temperature |
| A5 or A 5 | A 5 / A 5.1 | Low pressure |
| J2 or J 2 | J 2 / J 2.U | Branch 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.
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
| Flashes | Indoor Unit Error Code | Code Meaning / Code Related to: |
| 1 | EH 0 / EH 0A / E0 | Indoor EEPROM Microcontroller memory |
| 2 | EL 01 / E1 | Indoor/Outdoor units not communicating |
| 3 | EH 02 | Zero-crossing signal detection |
| 4 | EH 03 / E3 | Indoor fan operating outside normal range |
| 5 | EC 51 | Outdoor EEPROM |
| 5 | EC 52 / F2 | T3 Condenser coil sensor open or short-circuited |
| 5 | EC 53 / F1 | T4 Bad ambient air temperature sensor |
| 5 | EC 54 | TP or T5 Bad compressor discharge temperature sensor |
| 5 | EC 56 / E5 | T2B Bad compressor coil sensor |
| 6 | EH 60 / E4 | T1 Bad indoor room temperature sensor |
| 6 | EH 61 | T2 Bad compressor coil sensor (see EC56) |
| 12 | EC 07 | Outdoor fan operation outside normal range |
| 9 | EH OB | Indoor PCB communication |
| 8 | EL OC / EC | Refrigerant leak detection |
| 7 | PC 00 / P0 | IPM malfunction or IGBT OSCP – Over current fault |
| 2 | PC 01 / P1 | High pressure protection |
| 3 | PC 02 / P2 | Compressor or IPM high temperature/pressure protection |
| 5 | PC 04 / P4 | Inverter compressor drive fault |
| 1 | PC 08 | Current overload protection |
| 6 | PC 40 | Communication fault between outdoor chips |
| 7 | PC 03 | Low-pressure (refrigerant) protection |
| 1 | P5 | Indoor unit mode conflict |
| 9 | EH B1 (or EH b1) | Indoor board communication fault |
| 11 | FH Od | Ionizer malfunction |
| Outdoor Unit Error Code | Code Meaning / Code Related to: |
| E0 | Outdoor EEPROM Fault |
| E2 | Indoor/Outdoor unit communication |
| E3 | IPM board / outdoor board communication |
| E4 | Bad outdoor unit temp sensor |
| E5 | Voltage protection |
| E8 | Outdoor fan speed |
| F1 | No “A” indoor unit coil outlet temp sensor – or bad sensor |
| F2 | No “B” indoor unit coil outlet temp sensor – or bad sensor |
| F3 | No “C” indoor unit coil outlet temp sensor – or bad sensor |
| F4 | No “D” indoor unit coil outlet temp sensor – or bad sensor |
| F5 | No “E” indoor unit coil outlet temp sensor – or bad sensor |
| P1 | High pressure protection |
| P2 | Low pressure protection |
| P3 | Compressor current protection |
| P4 | Compressor temp protection |
| P5 | Condenser high-temp protection |
| P6 | IPM 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 Code | Code Meaning / Code Related to: |
| E0 | Indoor/outdoor unit not communicating |
| Alt. E0 | Indoor unit EEPROM fault |
| EC | Outdoor communication fault |
| Alt. EC | Refrigerant leak detection |
| E1 | Bad room temperature sensor |
| Alt. E1 | Indoor/Outdoor unit not communicating |
| E2 | Bad indoor coil temperature sensor |
| Alt. E2 | Indoor pipe/coil temperature sensor |
| E3 | Bad outdoor coil temperature sensor |
| Alt. E3 | Outdoor pipe/coil temperature sensor |
| E4 | General system fault |
| E5 | Configuration fault |
| E6 | Indoor fan motor |
| E7 | Bad outdoor temperature sensor |
| E8 | Bad exhaust temperature sensor |
| E9 | Power module fault |
| EF | Bad outdoor fan module |
| EA | Current sensor fault |
| EE | EEPROM fault |
| EP | Bad temperature switch |
| EU | Bad voltage sensor |
| EH | Bad intake temperature sensor |
| F1 | Bad outdoor temperature sensor T4 |
| F2 | Bad coil temperature sensor T3 |
| F3 | Bad compressor temperature sensor |
| F4 | Outdoor unit EEPROM fault |
| P1 | Protection from over or undervoltage |
| P2 | Overcurrent protection |
| Alt. P2 | High temperature protection – compressor |
| P4 | Exhaust temperature protection |
| Alt. P4 | Inverter compressor drive fault |
| P5 | Subcooling |
| P6 | Overheating protection – AC Mode |
| P7 | Overheating protection Heating Mode |
| P8 | Outdoor overtemperature/undertemperature protection |
| P9 | Software control – drive protection |
| P0 | Hardware 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 Code | Code Meaning / Code Related to: |
| EO | System transmission / remote / communication fault |
| E0, E1, E2, E3, E4, E5 | Remote controller issues |
| E6, E7, E8, E9 | Indoor/outdoor units not communicating |
| P1 | TH1 – Thermistor 1 – Return air thermistor |
| P2 | TH2 – Thermistor 2 – Coil/pipe thermistor |
| P3 | System communication fault |
| P4 | Drain sensor |
| P5 | High condensate – drain issues |
| P6 | Freezing/Overheating of indoor unit |
| P7 | System error – Turn system off and back on |
| P8 | Abnormal pipe temperature |
| P9 | TH5 Condenser/evaporator thermistor fault |
| U1 | High pressure trip – Outside unit blockages |
| U2 | High discharge temperature – Overheating outdoor unit |
| U3 | Discharge thermistor fault |
| U4 | Outdoor thermistor fault |
| U5 | TH8/Thermistor 8 – Inverter sink temperature too high |
| U6 | Compressor over current protection |
| U7 | Low discharge superheat – Outdoor unit |
| E6, E7 | Indoor/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 Samsunghvac.com.
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.
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:
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 Code | Code Meaning / Code Related to… |
| C5 | Jumper cap malfunction protection |
| EE | Loading EEPROM malfunction |
| EU | Frequency limiting module temp |
| E1 | High pressure protection |
| E2 | Anti-freezing protection |
| E3 | Low refrigerant pressure |
| E4 | Compressor exhaust temp too high |
| E5 | AC over-current protection |
| E6 | Communication failure indoor/outdoor units |
| E8/H4 | Anti-high temp protection |
| Fo | Gathering refrigerant (recovery) |
| F1 | Indoor ambient sensor open/short-circuit |
| F2 | Indoor tube sensor or evaporator sensor open/short-circuit |
| F3 | Outdoor ambient sensor open/short-circuit |
| F4 | Outdoor tube sensor open/short-circuit |
| F5 | Exhaust /outdoor discharge sensor |
| F6 | Overload limit |
| F8 | Over current limit |
| F9 | High exhaust temp limit |
| F0 | Refrigerant leak protection |
| FH | Anti-freezing limit |
| HC | PFC protection |
| H1 | Defrosting |
| H3 | Compressor overload protection |
| H5/P5 | IPM protection/Module temp too high |
| H6 | Indoor fan motor not giving feedback |
| JF | Detection plate malfunction |
| LP | Incompatible indoor/outdoor units |
| LU | Frequency limiting power |
| L3 | Outdoor DC fan malfunction |
| L9 | Power protection |
| PH | High PN voltage protection |
| PL | Low PN voltage protection |
| PU | Capacitor charging malfunction |
| P7 | Temp sensor module malfunction |
| P8 | High temperature protection module |
| UL | 4-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 Code | Code Meaning – Code related to… |
| C5 | Indoor configuration jumper missing on control board |
| LP | Indoor/outdoor units are not compatible |
| PL | Low voltage |
| E1 | High pressure protection |
| E5 | High current protection/voltage range too large |
| E6 | Communication error – possible wiring error |
| E7 | Mode conflict in multizone systems |
| F0 | Low refrigerant / possible leak |
| F1 | Indoor air temp – bad connection or sensor |
| F2 | Indoor coil temp – bad connection or sensor |
| F3 | Outdoor air temp sensor – bad connection or sensor |
| F4 | Outdoor coil temp – bad connection or sensor |
| F5 | Compressor discharge temp – bad connection or sensor |
| H1 | Defrosting – Not an error |
| H3 | Compressor overload protection – Low refrigerant or blockage |
| H4 | Restart required |
| H5 | IPM module protection – temp too high |
| H6 | Indoor fan malfunction |
| H7 | Compressor synch: high pressure, low voltage, bad connection |
| U7 | 4-way valve malfunction |
| U8 | Restart 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 Code | Code Meaning – Error related to… |
| 0 or 00 | Normal |
| UA | Indoor/outdoor unit combination doesn’t match |
| U0 | Low refrigerant |
| U2 | Drop voltage / main circuit overvoltage |
| U4 | Indoor/outdoor unit communication/transmission fault |
| U7 | Signal transmission error outdoor unit PCB |
| A1 | Indoor PCB defective |
| A5 | High pressure control / freeze-up protection |
| A6 | Fan motor |
| C4 | Bad heat exchanger temp sensor or thermistor |
| C9 | Faulty suction air temp sensor or room temp thermistor |
| EA | Cool/Heat mode switching error |
| E1 | Circuit board |
| E5 | OL activation – compressor overload |
| E6 | Compressor startup fault |
| E7 | DC fan motor fault |
| E8 | Input overcurrent detection |
| F3 | High temp discharge pipe control |
| F6 | AC mode high pressure control |
| H0 | Bad sensor |
| H6 | Operation halt – faulty position detection sensor |
| H8 | Bad DC current sensor |
| H9 | Bad suction air temp sensor |
| J3 | Bad discharge pipe temp sensor |
| J6 | Bad heat exchanger temp sensor |
| L3 | Electrical parts overheat |
| L4 | High temperature at inverter circuit heatsink |
| L5 | Output overcurrent |
| P4 | Faulty inverter circuit – Heatsink temperature sensor |
Reference:
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 Code | Code Meaning – Error related to… |
| E0 | Indoor unit EEPROM parameter fault |
| E1 | Indoor/outdoor units not communicating |
| E2 | Zero-crossing signal detection |
| E3 | Indoor fan speed control |
| E4 | Bad indoor room temp sensor T1 |
| E5 | Bad T2 evaporator coil sensor |
| EC | Refrigerant leak |
| F0 | Overload current protection |
| F1 | Bad T4 outdoor ambient temperature sensor |
| F2 | Bad T3 condenser coil sensor |
| F3 | Bad TP compressor discharge temperature sensor |
| F4 | Outdoor unit EEPROM parameter fault |
| F5 | Outdoor fan speed control |
| P0 | IPM malfunction or IGBT over-strong current protection |
| P1 | Over voltage or over low voltage protection |
| P2 | High temperature protection of IPM module or compressor |
| P3 | Outdoor ambient temperature too low for safe operation |
| P4 | Inverter compressor drive |
| P5 | Multizone systems – Indoor units in different modes |
| P6 | Low pressure protection |
