Mitsubishi Heavy Air Conditioner Error Codes
Mitsubishi Heavy Air Conditioner Error Codes

Mitsubishi Heavy Industries Air Conditioner Error Codes

Mitsubishi Heavy Industries Air Conditioner Error Codes help you know when your air conditioning system needs to be repaired or isn’t working as it should. Each error code has a meaning to help you understand the problem and what needs to be done to fix it.

Mitsubishi Heavy Industries Air Conditioner Error Code Solutions

Mitsubishi Heavy Industries units present an indication of self-diagnosis so when the air conditioner stops abnormally; the cause is indicated with lamps.

Three minutes after an abnormal stop, you can use the remote controller to start the appliance. The error indication should disappear and the appliance will commence operation, unless a more complex issue requires technical expertise.

1.Split Systems

Whether a failure exists or not on the indoor unit and outdoor unit can be know by the contents of remote controller eroor code, indoor/outdoor unit green LED (power pilot lamp and microcomputer normality pilot lamp) or red LED (check pilot lamp).

Mitsubishi Heavy Industries Air Conditioner Error Codes

a.Check Indicator Table;

Indoor Unit Side

Error CodesCause
E1When multiple remote controllers are used for control, the power supply to some indoor units is OFF.
Indoor unit PCB fault
The remote controller wire Y is open. The remote controller wires X and Y are reversely connected. Noise is penetrating the remote control lines. The remote controller or indoor control PCB is faulty.
E5Indoor / outdoor transmission error.
Outdoor unit control PCB is faulty when the power is turned on, or the inverter parts are faulty.
Outdoor unit microcomputer failure.
E6Indoor unit heat exchanger thermistor failure
E7Indoor unit return air thermistor failure
E8Heating overload (indoor heat exchanger temperature is abnormally high) and indoor heat exchanger thermistor is faulty.
E9The float SW operates (with FS only). Drain up kit wiring fault.
E10When multi-unit control by remote controller is performed, the number of units is over (more than 17 units). Two remote controller are provided for one controller is performed.
E16Fan motor is faulty (FDTA 501, 601 type, FDKN type)
E28Remote controller thermistor failure

Outdoor Unit Side

Error CodesCause
E32Wiring is open or reversal phase (FDCA 301~601 type)
E33Inverter primary side current is abnormal. (FDCVA151~251 type)
Abnormal current cut of compressor (FDCA 301~601 type)
E3452C secondary side L3-phase wiring is open. (FDCA 301~601 type)
E35Outdoor heat exchanger temperature is high or outdoor heat exchanger thermistor is faulty
E36Discharge temperature abnormality.
E37Outdoor unit heat exchanger thermistor failure
E38Outdoor air temperature thermistor failure
E39Discharge pipe thermistor failure
E4063H1 operation (FDCA 301~601 type)
E42Current (Abnormalities in a compressor over current)
E47Inverter Over-voltage Trouble. (FDCVA 151~251 type)
E48DC fan motor abnormal. (FDCVA 151~251 type)
E5252C abnormal. (FDCA 301~601 type)
E56Power transistor thermistor is faulty or disconnection or connector connections are poor.
E57Insufficient refrigerant.
E59Compressor startup error (FDCVA 151~251 type)
E60Compressor loader position detection error. (FDCVA 151~251 type)
Mitsubishi Heavy Air Conditioner Error Codes

b.Display Sequence of Error, Inspection Display Lamp;

Error CodesError Detail
Indoor Unit Side
E1Transmission error of remote controller indoor unit. Timing of error detection: After 1 or more communications of the indoor unit with the remote controller following power on, transmission errors cause an interruption for 2 minutes.
E5Transmission error between indoor/outdoor units. Timing of error detection: After communications with the outdoor unit 1 or more times, communications are abnormal continuously for 2 minutes.
E6Broken wire of heat exchanger thermistor. Timing of error detection: When an input temperature of –50°C or lower is measured by the heat exchanger thermistor is measured for 5 seconds or longer within 60 minutes after the first detection.
E7Broken wire of indoor unit return air thermistor. Timing of error detection: When an input temperature of –50°C or lower is measured by the return air thermistor is measured for 5 seconds or longer within 60 minutes after the first detection.
E9Drain error (float switch motion). Timing of error detection: Normally, 30 seconds after the power is turned ON
E10The number of connected indoor units exceeds the connection limit. Timing of error detection: Normally after the power is turned ON (during communications).
Outdoor Unit Side
E38Broken wire of outdoor air temperature thermistor. Timing of error detection: When a thermistor input temperature of –30°C or lower is measured for 5 seconds or longer 3 times within 40 (60) minutes after the 1st detection between 2 minutes and 2 minutes 20 seconds after compressor operation starts.
E37Broken wire of heat exchanger thermister. Timing of error detection: When a thermistor input temperature of –30°C or lower is measured for 5 seconds or longer 3 times within 40 (60) minutes after the 1st detection between 2 minutes and 2 minutes 20 seconds after compressor operation starts.
E39Broken wire of discharge pipe thermistor. Timing of error detection: When a thermistor input temperature of –10°C or lower is measured for 5 seconds or longer 3 times within 40 (60) minutes after the 1st detection between 10 minutes and 10 minutes 20 seconds (between 2 minutes and 2 minutes 20 seconds) after compressor operation starts.
E55Broken wire of power transistor thermistor. Timing of error detection: When the under-dome thermistor input temperature of –10°C is measured for 5 seconds or longer 3 times within 40 minutes after the 1st detection between 10 minutes and 10 minutes 20 seconds after compressor operation starts.
Mitsubishi Heavy Industries Air Conditioner Error Codes

Inverter Wall Mounted Type Room AC Error Codes

Error code, stop code table (Assignment of error codes and stop codes is done in common for all models.)

MHI VRF Inverter Multi System Error Codes
Remote Control Error CodesDescription of Fault
E1Remote controller communication error. Possible Cause: Anomalous communication circuit between remote controller and indoor unit, Noise.
E2Duplicated indoor unit addressing more than 49 units connected. Possible Cause: Number of connected indoor units exceeds the limitation, Duplicated indoor unit address, Indoor PCB anomaly.
E3Outdoor unit signal line error. Possible Cause: Power is not suppied to outdoor unit, Unmatch of pairing between indoor and outdoor units, Indoor PCB anomaly, Outdoor control PCB anomaly, Missing local wiring.
E5Communication error during operation. Possible Cause: Unit address No. setting error, Remote control wires broken, Poor connection/ disconnection of remote controller wires, Indoor control PCB anomaly, Noise.
E6Indoor heat exchanger temp. sensor anomaly (Thi-R). Possible Cause: Sensor anomaly, Poor connection, Indoor control PCB anomaly.
E7Indoor return air temp. sensor anomaly (Thi-A). Possible Cause: Sensor anomaly, Poor connection, Indoor control PCB anomaly.
E9Drain trouble. Possible Cause: Blocked drain, Drain pump anomaly, Float switch anomaly, Indoor contyrol PCB anomaly.
E10Excessive number of indoor units by controlling one renote controller. Possible Cause: Excessive number of indoor units connected (more than 17 units), Remote controller anomaly.
E11Address setting error (setting with remote controller). Possible Cause: When plural indoor units are connected, do not use remote controller address setting method.
E12Address setting error by mixed setting method. Possible Cause: The atomatic setting and manual setting mixed in the address setting method for indoor units.
E16Indoor fan motor anomaly. Possible Cause: Fan motor anomaly, Poor connection, Indoor PCB anomaly.
E18Address setting error of master and slave indoor remote controller. Possible Cause: Remote controller SW address setting error of master and slave indoor units.
E19Indoor unit operation check, drain motor check mode anomaly. Possible Cause: Mistake in SW7-1 setting due to forgetting to turn OFF SW7-1 after indoor operation check finished.
E20Indoor fan motor rotationtion speed anomaly (FDT, FDTC, FDK, FDTW). Possible Cause: DC fan motor revolution speed anomaly, Indoor power (control) PCB anomaly, Foreign material at rotational area of fan motor.
E21FDT Limit switch is not activated. Possible Cause: Limit switch on the panel anomaly, Anomalous mounting position of gille, Connector CNV loose.
E22Wrong connection with Outdoor unit. Possible Cause: Unmatched pairing of indoor and outdoor unit, Indoor control PCB anomaly, Outdoor control PCB anomaly.
E28Remote controller temp. sensor anomaly (Thc). Possible Cause: Remote controller temp. sensor anomaly, Poor connection, Remote controller PCB anomaly.
E30Unmatch connection of indoor and outdoor unit. Possible Cause: Indoor control PCB anomaly, Outdoor control PCB anomaly.
E31Duplicated outdoor unit address No.. Possible Cause: Mistake in the address setting of outdoor units, More than 129 indoor units connected, No setting of Master/Slave setting switch for combination use.
E32Open L3 phase on power supply at primary side. Possible Cause: Anomalous power supply at primary side, Outdoor control PCB anomaly.
E361.Discharge pipe temp. sensor anomaly, Outdoor control PCB anomaly, Short circuit of airflow, Insufficient airflow volume, Insufficient amount of refrigerant, SV1, 2 (liquid refrigerant by pass valve) anomaly. 2. Liquid flooding anomaly. Overcharging of refrigerant, Superheat control anomaly, Circuit of liquid refrigerant by pass anomaly, Discharge pipe temp. sensor anomaly, EEV indoor anomaly.
E37Outdoor heat exchanger temp. sensor (Tho-R) and subcooling coil temp. sensor (Tho-SC, -H) anomaly. Possible Cause: Broken sensor harness or the internal wire of sensing section, Poor connection, Outdoor contron PCB anomaly.
E38Outdoor air temp. sensor anomaly  (Tho-A). Possible Cause: Broken sensor harness or the internal wire of sensing section, Poor connection, Outdoor contron PCB anomaly.
E39Discharge pipe temp. sensor anomaly (Tho-D1, D2). Possible Cause: Broken sensor harness or the internal wire of sensing section, Poor connection, Outdoor contron PCB anomaly.
E40High pressure anomaly (63H1-1,2 activated). Possible Cause: Disconnection of high pressure switch connector, High pressure sensor anomaly, High pressure switch anomaly, Short circuit of airflow at condenser, Close service valve.
E41Power transistor overheat. Possible Cause: Power transistor anomaly, Power transistor temp. sensor anomaly, Improperly fixing of power transistor to radiator fin, Inverter PCB anomaly, Outdoor fan motor anomaly, Cooling fan motor for inverter anomaly, Inadequate installation space of outdoor unit.
E51Power transistor overheat. Possible Cause: Power transistor anomaly, Power transistor temp. sensor anomaly, Improperly fixing of power transistor to radiator fin, Inverter PCB anomaly, Outdoor fan motor anomaly, Cooling fan motor for inverter anomaly, Inadequate installation space of outdoor unit.
E42Current cut (CM1, CM2). Possible Cause: Compressor anomaly, Leakage of refrigerant, Power transistor module anomaly, Anomalous power supply for inverter PCB, Outdoor fan motor anomaly.
E43Excessive number of indoor units connected, excessive total capacity. Possible Cause: Mistake in setting of indoor/outdoor unit addresses, Mistake in signal wire connection.
E45Communication error between inverter PCB and outdoor control PCB. Possible Cause: Signal wire anomaly, Outdoor control PCB anomaly, Inverter PCB (INV1,2) anomaly, Rush current prevention resistor anomaly.
E46Mixed address setting methods conexistent in same network. Possible Cause: Mistake in the address setting, Mistake in the connection of signal wire.
E48Outdoor DC fan motor anomaly. Possible Cause: Outdoor fan motor anomaly, Poor connection, Inverter PCB anomaly, Outdoor control PCB anomaly.
E49Low pressure anomaly. Possible Cause: Low pressure sensor anomaly, Service valves closed, EEV anomaly (EEV closed), Insufficient refrigerant amount, Clogging at EEV or strainer.
E53Suction pipe temp. sensor anomaly (Tho-S). Possible Cause: Broken sensor harness or the internal wire of sensing section, Poor connection, Outdoor contron PCB anomaly.
E54High pressure sensor anomaly (PSH)/ Low pressure sensoe anomaly (PSL). Possible Cause: Broken sensor harness, Disconnection of sensor, Sensor (PSH, PSL) anomaly, Outdoor control PCB anomaly, Anomalous installation condition, Insufficient airflow volume, Excessive or insufficient refrigerant amount.
E55Under-dome temp. sensor anomaly (Tho-C1, C2). Possible Cause: Broken sensor harness or the internal wire of sensing section, Poor connection, Outdoor contron PCB anomaly.
E56Power transistor temp. senser anomaly (Tho-P1, P2). Possible Cause: Broken sensor harness or the internal wire of sensing section, Poor connection, Outdoor contron PCB anomaly.
E58Anomalous compressor by loss of synchronism. Possible Cause: Insufficient time elapsed after the power supplied before compressor startup, Startup compressor without crankcase heater ON, Compressor anomaly.
E59Compressor startup failure (CM1, CM2). Possible Cause: Anomalous voltage of power supply, Anomalous components for refrigerant circuit, Inverter PCB anomaly, Loose connection of connector or cable, Compressor anomaly (Motor or bearing)
E60Rotor position detection failure (CM1, CM2). Possible Cause: Compressor anomaly, Inverter PCB anomaly, Anomaly of power supply.
E61Communication error between the master unit and slave units. Possible Cause: Signal wire anomaly, Outdoor control PCB anomaly, Inverter PCB (INV1,2) anomaly, Rush current prevention resistor anomaly.
E63Emergency stop. Possible Cause: Factors for emergency stop.
E75Central control communication error. Possible Cause: Poor connection, faulty controller.
Mitsubishi Heavy Industries Wired Remote Control

Mitsubishi Heavy Industries AC Self-diagnosis Table

When this air conditioner performs an emergency stop, the reason why the emergency stop occurred is displayed by the flashing of display lights. If the air conditioner is operated using the remote control 3 minutes or more after the emergency stop, the trouble display stops and the air conditioner resumes operation.

Mitsubishi heavy industries air conditioner timer light flashing:

RUN lightTIMER lightOutdoor unit LEDWired remote control displayDescription of troubleCauseDisplay (flashing) condition
1 time flashONHeat exchanger sensor 1 errorBroken heat exchanger sensor 1 wire, poor connector connectionWhen a heat exchanger sensor 1 wire disconnection is detected while operation is stopped. (If a temperature of –28ºC or lower is detected for 15 seconds, it is judged that the wire is disconnected.) (Not displayed during operation.)
2 time flashONRoom temperature sensor errorBroken room temperature sensor wire, poor connector connectionWhen a room temperature sensor wire disconnection is detected while operation is stopped. (If a temperature of –45ºC or lower is detected for 15 seconds, it is judged that the wire is disconnected.) (Not displayed during operation.)
3 time flashONHeat exchanger sensor 3 errorBroken heat exchanger sensor 3 wire, poor connector connectionWhen a heat exchanger sensor wire 3 disconnection is detected while operation is stopped. (If a temperature of –28ºC or lower is detected for 15 seconds, it is judged that the wire is disconnected.) (Not displayed during operation.)
6 time flashONE16Indoor fan motor errorDefective fan motor, poor connector connectionWhen conditions for turning the indoor unit’s fan motor on exist during air conditioner operation, an indoor unit fan motor speed of 300 rpm or lower is measured for 30 seconds or longer. (The air conditioner stops.)
Keeps flashing1 time flash8 time flashE38Outdoor air temperature sensor errorBroken outdoor air temp. sensor wire, poor connector connectionWhen an outdoor temperature sensor wire disconnection is detected while the power is turned on or after the outdoor unit’s speed has continued at 0rps or higher for 2 minutes. (If a temperature of –55ºC or lower is detected for 20 seconds, it is judged that wire is disconnected.) (The compressor is stopped.)
Keeps flashing2 time flash8 time flashE37Outdoor heat exchanger sensor erroBroken heat exchanger sensor wire, poor connector connectionWhen a heat exchanger sensor wire disconnection is detected while the power is turned on or after the outdoor unit’s speed has continued at 0rps or higher for 2 minutes. (If a temperature of –55ºC or lower is detected for 20 seconds, it is judged that wire is disconnected.) (The compressor is stopped.)
Keeps flashing4 time flash8 time flashE39Discharge pipe sensor errorBroken discharge pipe sensor wire, poor connector connectionWhen a discharge pipe sensor wire disconnection is detected after the outdoor unit’s speed has continued at 0rps or higher for 10 minutes. (If a temperature of –25ºC or lower is detected for 20 seconds, it is judged that wire is disconnected.) (The compressor is stopped.)
ON1 time flash1 time flashE42Current CutCompressor locking, open phase on compressor output, shortcircuit on power transistor, closed service valveThe inverter output current (compressor motor current) exceeds the set value during compressor start. (The air conditioner stops.)
ON2 time flash2 time flashE59Trouble of outdoor unitBroken compressor wire. Compressor blockage.When there is an emergency stop caused by trouble in the outdoor unit, or the input current value is found to be lower than the set value. (The air conditioner stops.)
ON3 time flash3 time flashE58Current safe stopOverload operation. Overcharge. Compressor locking.When the inverter command speed is lower than the set value and the current safe has operated. (the compressor stops)
ON4 time flash1 time flashE51Powe rtransistor errorBroken power transistorWhen the power transistor is judged breakdown while compressor starts. (The compressor is stopped.)
ON5 time flash5 time flashE36Over heat of ON compressorGas shortage, defective discharge pipe sensor, closed service valveWhen the value of the discharge pipe sensor exceeds the set value. (The air conditioner stops.)
ON6 time flash6 time flashE3-E5Error of signal transmissionDefective power supply, Broken signal wire, defective in/outdoor unit boards.When there is no signal between the indoor unit’s board and outdoor unit’s board for 10 seconds or longer (when the power is turned on), or when there is no signal for 7 minute 35 seconds or longer (during operation)(the compressor is stopped).
ON7 time flashONE48Outdoor fan motor errorDefective fan motor, poor connector connectionWhen the outdoor unit’s fan motor speed continues for 30 seconds or longer at 75 rpm or lower. (3 times) (The air conditioner stops.)
ONKeeps flashing2 time flashE35Cooling high pressure protectonOverload operation, overcharge. Broken outdoor heat exchange sensor wire. Closed service valve.When the value of the outdoor heat exchanger sensor exceeds the set value.
2 time flash2 time flash7 time flashE60Rotor lockDefective compressor. Open phase on compressor. Defective outdoor unit boards.If the compressor motor’s magnetic pole positions cannot be correctly detected when the compressor starts. (The air conditioner stops.)
5 time flashON2 time flashE47Active filter ON voltage errorDefective active filterWhen the wrong voltage connected for the power supply. When the outdoor control PCB is faulty
E1Error of wired remote control wiringBroken wired remote control wire, defective indoor unit boardsThe wired remote control wire Y is open. The wired remote control wires X and Y are reversely connected. Noise is penetrating the wired remote control lines. The wired remote control or indoor control PCB is faulty. (The communications circuit is faulty.)

Mitsubishi Heavy Industries Air Conditioner Error Codes

Error code, stop code table (Assignment of error codes and stop codes is done in common for all models.)

RUN light (10’s digit)TIMER light (1’s digit)Stop code or Error codeError content-Cause-Occurrence conditions
OFFOFF0Normal
OFF5 time flash05Can not receive signals for 35 seconds (if communications have recovered). Power supply is faulty. Power supply cables and signal lines are improperly wired. Indoor or outdoor unit circuit boards are faulty. When 35 seconds passes without communications signals from either the outdoor unit or the indoor unit being detected correctly.
3 time flash5 time flash35Cooling high pressure control. Cooling overload operation. Outdoor unit fan speed drops. Outdoor heat exchanger sensor is short circuit. When the outdoor heat exchanger sensor’s value exceeds the set value.
3 time flash6 time flash36Compressor overheat (115˚C). Refrigerant is insufficient. Discharge pipe sensor is faulty. Service valve is closed. When the discharge pipe sensor’s value exceeds the set value.
3 time flash7 time flash37Outdoor heat exchanger sensor is abnormal. Outdoor heat exchanger sensor wire is disconnected. Connector connections are poor. When a temperature of –55˚C or lower is sensed continuously for 20 seconds while the power is turned on or after the outdoor unit’s speed has continued at 0rps or higher for 2 minutes (the compressor stops).
3 time flash8 time flash38Outdoor air temperature sensor is abnormal. Outdoor air temperature sensor wire is disconnected. Connector connections are poor. When a temperature of –55˚C or lower is sensed continuously for 20 seconds while the power is turned on or after the outdoor unit’s speed has continued at 0rps or higher for 2 minutes (the compressor stops).
3 time flash9 time flash39Discharge pipe sensor is abnormal (anomalous stop). Discharge pipe sensor wire is disconnected. Connector connections are poor. When a temperature of –25˚C or lower is sensed continuously for 20 seconds after the outdoor unit’s speed has continued at 0rps or higher for 10 minutes (the compressor stops).
4 time flash2 time flash42Current cut. Compressor lock. Compressor wiring short circuit. Compressor output is open phase. Outdoor unit’s circuit board is faulty. Service valve is closed. Electronic expansion valve is faulty. Compressor is faulty. Compressor start fails 42 times in succession and the reason for the final failure is current cut.
4 time flash7 time flash47Active filter voltage error. Defective active filter. When the wrong voltage connected for the power supply. When the outdoor control PCB is faulty
4 time flash8 time flash48Outdoor unit’s fan motor is abnormal. Outdoor fan motor is faulty. Connector connections are poor. Outdoor unit’s circuit board is faulty. When a fan speed of 75 rpm or lower continues for 30 seconds or longer.
5 time flash1 time flash51Short circuit in the power transistor (high side) Current cut circuit breakdown. Outdoor unit’s circuit board is faulty. Power transistor is damaged. When it is judged that the power transistor was damaged at the time the compressor started.
5 time flash7 time flash57Refrigeration cycle system protective control. Service valve is closed. Refrigerant is insufficient. When refrigeration cycle system protective control operates.
5 time flash8 time flash58Current safe. Refrigerant is overcharge. Compressor lock. Overload operation. When there is a current safe stop during operation.
5 time flash9 time flash59Compressor wiring is unconnection Voltage drop Low speed protective control. Compressor wiring is disconnected. Power transistor is damaged. Power supply construction is defective. Outdoor unit’s circuit board is faulty. When the current is 1A or less at the time the compressor started. When the power supply voltage drops during operation. When the outdoor unit’s speed is lower than 26 rps for 60 minutes.
6 time flashOFF60Rotor lock. Compressor is faulty. Compressor output is open phase. Electronic expansion valve is faulty. Overload operation. Outdoor unit’s circuit board is faulty. After the compressor starts, when the compressor stops due to rotor lock.
6 time flash1 time flash61Connection lines between the indoor and outdoor units are faulty. Connection lines are faulty. Indoor or outdoor unit circuit boards are faulty. When 10 seconds passes after the power is turned on without communications signals from the indoor or outdoor unit being detected correctly.
6 time flash2 time flash62Serial transmission error. Indoor or outdoor unit circuit boards are faulty. Noise is causing faulty operation. When 7 minute 35 seconds passes without communications signals from either the outdoor unit or the indoor unit being detected correctly.
8 time flashOFF80Indoor unit’s fan motor is abnormal. Indoor fan motor is faulty. Connector connections are poor. Indoor unit’s circuit board is faulty. When the indoor unit’s fan motor is detected to be running at 300 rpm or lower speed with the fan motor in the ON condition while the air conditioner is running.
8 time flash2 time flash82Indoor heat exchanger sensor is abnormal (anomalous stop). Indoor heat exchanger sensor wire is disconnected. Connector connections are poor. When a temperature of –28˚C or lower is sensed continuously for 40 minutes during heating operation. (the compressor stops).
8 time flash4 time flash84Anti-condensation control. High humidity condition. Humidity sensor is faulty. Anti-condensation prevention control is operating.
8 time flash5 time flash85Anti-frost control. Indoor unit fan speed drops. Indoor heat exchanger sensor is broken wire. When the anti-frost control operates and the compressor stops during cooling operation.
8 time flash6 time flash86Heating high pressure control. Heating overload operation. Indoor unit fan speed drops. Indoor heat exchanger sensor is short circuit. When high pressure control operates during heating operation and the compressor stops.

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