Mitsubishi Air Conditioner Error Codes

Air conditioner manufacturers often include error codes in their manual for user reference. If you no longer have the manual for your unit, check our list below for the list of Mitsubishi error codes by unit model.

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Mitsubishi 4-Digit Error Codes

• 0403: Serial communication error
• 0900: Test run
• 1102: Discharge temperature fault
• 1111: Low pressure or temperature fault
• 1112: Low pressure or temperature fault
• 1113: Low pressure or temperature fault
• 1202: Preliminary fault to 1102
• 1204: Preliminary fault to heat exchanger gas temperature sensor
• 1205: Preliminary fault to thermistor (TH5)
• 1211: Preliminary fault to thermistor (TH2)
• 1214: Preliminary fault to thermistor (THHS)
• 1216: Preliminary fault to thermistor (TH7)
• 1217: Preliminary fault to thermistor (TH8)
• 1219: Preliminary fault to thermistor (TH9)
• 1221: Preliminary fault to thermistor (TH6)
• 1243: Preliminary fault to thermistor (TH10)
• 1301: Low pressure fault
• 1302: High pressure fault
• 1368: Pressure sensor fault (PS1)
• 1370: Pressure sensor fault (PS3)
• 1402: Preliminary fault to 1302
• 1500: Refrigerant overcharge
• 1501: Compressor shell overheating
• 1505: Abnormal suction pressure
• 2500: Drain sensor submergence
• 2502: Drain pump fault
• 2503: Drain sensor fault
• 2600: Water leak
• 4100: Compressor overcurrent protection
• 4101: Compressor overcurrent protection
• 4102: Open phase
• 4106: Transmission power supply fault
• 4108: Overcurrent protection on DOL compressor
• 4115: Power supply signal sync error
• 4116: RPM error / Motor error
• 4124: Thermal switch (49C) open circuit
• 4210: Compressor overcurrent problem
• 4220: Abnormal bus voltage
• 4225: Low bus voltage
• 4230/4260: Heatsink overheat protection activated
• 4235: Fan inverter heat sink overheating protection
• 4240: Overload protection activated
• 4245: Overcurrent protection; Possible ACCT current sensor fault
• 4250: Overcurrent protection activated
• 4255: Outdoor unit fan error
• 4260: Preliminary inverter heat sink overheating protection
• 5101: Temperature sensor fault
• 5102: Return air thermistor fault
• 5103: Thermistor fault at indoor or outdoor unit
• 5104: Thermistor fault at indoor or outdoor unit
• 5105: TH5 open or short circuit
• 5106: TH6 open or short circuit
• 5107: TH7 open or short circuit
• 5108: TH8 open or short circuit
• 5109: TH9 open or short circuit
• 5110: Outdoor unit inverter heat sink thermistor error
• 5111: TH 11 open or short circuit
• 5112: TH10 open or short circuit
• 5113: TH open or short circuit
• 5114: TH open or short circuit
• 5115: TH15 open or short circuit
• 5116: TH16 open or short circuit
• 5201: Pressure sensor fault
• 5202: Pressure sensor fault (PS2)
• 5203: Pressure sensor fault (PS3)
• 5300: A-control UH fault
• 5301: Current sensor fault
• 5401: Temperature sensor fault
• 5701: Loose float switch
• 6201: Remote controller issue
• 6202: Transmission processor hardware error
• 6600: Address overlap
• 6601: Polarity setting error
• 6602: Transmission processor hardware error
• 6603: Transmission line busy
• 6606: Communication fault
• 6607: No ACK
• 6608: No response
• 6700/6701: Communication error between R22 type unit and M-Net circuit
• 6702: Two or more R22 type units connected to M-Net circuit with the same address
• 6751: R22 R/A thermistor fault (P1)
• 6752: R22 frost protection at indoor unit (P6)
• 6753/6758: Communication error between indoor and outdoor unit
• 6754/6755: R22 drain fault (P5)
• 6756/6766: R22 frost protection at indoor unit (P6)
• 6757: System error
• 6761: R22 R/A thermistor fault (P2)
• 6762: R22 TH2 fault check resistance (P2)
• 6763/6767: R22 communication error between indoor and outdoor unit
• 6764: R22 drain fault (P4)
• 6831/6834: MA controller signal reception error
• 6832/6833: MA controller comms fault
• 6840: A-Control E6/E8 fault
• 6841: A-Control E7/E9 fault
• 6844: A-Control EA fault
• 6845: A-Control Eb fault
• 6846: A-Control E6 fault
• 7100: Total capacity error
• 7101: Capacity code setting error
• 7102: Wrong number of connected units
• 7105: Address setting error
• 7106: Attribute setting error
• 7107: Port setting error
• 7110: Signal transmission error
• 7111: Remote controller sensor fault
• 7113: Function setting error
• 7117: Model setting error
• 7130: Incompatible unit combination

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Mitsubishi AC Error Codes

• E0/E3: Remote controller transmission error
• E1/E2: Remote controller control board error
• E4: Remote controller signal receiving error
• E6/E7: Indoor/outdoor unit communication error
• E8/E9/EC: Indoor/outdoor unit communication error (Transmitting error) (Outdoor unit)
• EE: Communication error between indoor and outdoor units
• Fb: Indoor unit control system error (memory error, etc.)
• FC: Nonvolatile memory data
• Fd: Different voltage
• P1: Intake sensor error
• P2/P9: Pipe (Liquid or 2-phase pipe) sensor error
• P4: Drain sensor error
• P5: Drain pump error
• P6: Freezing / Overheating safeguard operation
• P8: Pipe temperature error
• PA: Forced compressor error
• Pb: Indoor fan motor issue
• PL: Outdoor refrigerant system error
• U1/Ud: Abnormal high pressure (63H worked) / Overheating safeguard operation
• U2: Abnormal high discharging temperature / 49C worked/insufficient refrigerant
• U3: Discharge temperature thermistor
• U4: Issue with defrost thermistor, fin temperature thermistor, P.C. board temperature thermistor, ambient temperature thermistor, or outdoor heat exchanger temperature thermistor
• U5: Abnormal temperature of heat sink
• U6: Compressor overcurrent interruption / Abnormal of power module
• U7: Abnormality of superheat due to low discharge temperature
• U8: Outdoor unit fan safeguard stop
• U9: UH Abnormality such as overvoltage or voltage shortage and abnormal synchronous signal to main circuit / Current sensor error.
• UE: Stop valve (close valve)
• UF: Compressor overcurrent interruption (When compressor locked)
• UP: Compressor overcurrent interruption

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Mitsubishi Mr. Slim-A Control Error Codes

• A0: Duplicate address; Lossnay units attached using the same address
• A2: Hardware error transmission processor
• A3: No data transmission for 8 minutes due to busy line
• A6: Communication error with processor; Lossnay address not being transmitted
• A7: No ACK signal
• A8: No M-Net response
• E0: Remote control transmission error (signal receiving error)
• E0-E5: Signal error between remote control and indoor units
• E1: Remote control communication issue
• E2: Remote control transmission error
• E3: Remote control transmission error (transmitting error)
• E3/E5: Remote control communication/receiving error
• E4: Remote control transmission error (signal receiving error)
• E5: Remote control transmission error (transmitting error)
• E6: Indoor and outdoor unit communication error
• E6-EF: Communication error between indoor and outdoor units
• E7: Indoor and outdoor unit communication error
• E8: Indoor and outdoor unit communication error
• E9: Indoor and outdoor unit communication error
• EA: Miswiring of indoor/outdoor unit (Exceeded the number of indoor unit connections)
• EB: Miswiring of indoor/outdoor unit (Miswiring disconnection)
• EC: Start-up time over
• ED: Serial communication error between boards on outdoor unit due to incorrectly fitted M-Net interface board
• EF: M-NET transmission error
• Ed: Serial transmission error
• F1: Reverse phase detection
• F1-FA: Outdoor unit error
• F2: L3 open phase detection
• F3: 63L connector open
• F4: 49C connector open
• F5: 63H connector open
• F7: Reverse phase detection circuit (P.C. board) fault
• F8: Input circuit fault
• F9: Connector 2 or more open
• FA: L2-phased open phase or 51CM connector open
• LED E0: Diagnosis of malfunction Transmitting / Receiving signal error
• LED Flash: Check code display
• LED LD1: LED ON Compressor directive / LED Flash Reverse phase detect
• LED LD2: LED ON Heating directive / LED Flash Open phase detect
• LED LD3: LED ON During 63H1 operation / LED Flash Pipe sensor short/open
• LED LD4: LED ON Compressor ON / LED Flash High pressure switch (63H2) operation
• LED LD5: LED ON Outdoor fan ON / LED Flash Over current relay (51CM) operation
• LED LD6: LED ON 4-way valve ON / LED Flash Thermal switch (26C) operation
• LED LD7: LED ON Bypass valve ON / LED Flash Thermistor (TH3) overheat protection
• LED LD8: LED ON Crankcase heater ON / LED Flash Defective input
• LED ON: Operation status
• LED P1: Intake air sensor abnormal
• LED P2: Pipe sensor abnormal
• LED P3: System error (transmitting/receiving signal)
• LED P4: Drain sensor abnormal
• LED P5: Malfunctioning of the drain overflow protecting mechanism
• LED P6: Abnormality of the coil frost / overheating protection mode
• LED P7: System error (address)
• LED P8: Outdoor unit malfunction
• Mr.Slim K-control: PUH-EK Outdoor unit
• P1: Abnormality of room temperature thermistor (TH1)
• P2: Abnormality of pipe temperature thermistor/liquid (TH2)
• P4: Abnormality of drain sensor (DS)
• P5: Malfunction of drain-up machine
• P6: Freezing/overheating protection detect
• P8: Abnormality of pipe temperature
• P9: Abnormality of pipe temperature thermistor/condenser/evaporator (TH5)
• U0-UP: Outdoor unit error
• U1: Direct cut operation
• U2: Inner thermostat (49C) operation
• U3: Discharge thermistor short/open
• U4: Outdoor thermistor short/open
• U5: Inverter heat sink overheating
• U6: Compressor over current
• U7: Low discharge superheat (TH4)
• UA: Compressor overcurrent (terminal relay operation)
• UE: High pressure error (ball valve closed)
• UF: Compressor overcurrent (operating locked) cut off
• UH: Current sensor error
• UL: Abnormal low pressure
• Ud: Overheat protection

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Mitsubishi Mr. Slim Error Codes (Membrane Type Remote Controllers)

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Luce Aircon stands as a reliable air conditioning service and repair company in Singapore. Thanks to our technicians' extensive experience, we proficiently handle diverse air conditioner models, including Mitsubishi. Count on us to pinpoint and resolve any issues with your air conditioning system.

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