Mitsubishi Heavy air conditioner indicator lamps and blink codes
Many units show a fault only by blinking lamps. Find the pattern you see, then open the code.
| Code | How it shows | Meaning |
|---|---|---|
| 0 | RUN light: OFF TIMER light: OFF RUN light (10's digit): OFF TIMER light (1's digit): OFF | Normal |
| 01 | RUN light (10's digit): OFF TIMER light (1's digit): 1-time flash | Error of wired remote control wiring (When wired remote control was connected) (When… |
| 05 | RUN light (10's digit): OFF TIMER light (1's digit): 5-time flash | Can not receive signals for 35 seconds (if communications have recovered) |
| 11 | RUN light: 1 time flash TIMER light: 1 time flash Occurrence conditions: Compressor start fails 42 times in succession and the reason for the final failure is current cut Error display: yes (2 times) | Start of compressor program |
| 12 | RUN light: 1 time flash TIMER light: 2 time flash RUN lamp (tens place): Flash 1 time TIMER lamp (ones place): Flash 2 times | Below 20 rps |
| 13 | RUN light: 1 time flash TIMER light: 3 time flash RUN lamp (tens place): Flash 1 time TIMER lamp (ones place): Flash 3 times | Over 20 rps |
| 14 | RUN light: 1 time flash TIMER light: 4 time flash RUN lamp (tens place): Flash 1 time TIMER lamp (ones place): Flash 4 times | Over voltage (DC350V) |
| 15 | RUN light: 1 time flash TIMER light: 5 time flash RUN lamp (tens place): Flash 1 time TIMER lamp (ones place): Flash 5 times | Short circuit of power transistor (high voltage side) |
| 16 | RUN light: 1 time flash TIMER light: 6 time flash RUN lamp (tens place): Flash 1 time TIMER lamp (ones place): Flash 6 times | Power cut, loop failure |
| 17 | RUN light: 1 time flash TIMER light: 7 time flash | Software current cut |
| 21 | RUN lamp (tens place): Flash 2 times TIMER lamp (ones place): Flash 1 time | Abnormal result of PWM algorithm |
| 22 | RUN light: 2 time flash TIMER light: 2 time flash RUN lamp (tens place): Flash 2 times TIMER lamp (ones place): Flash 2 times | Input below 2A (PWM above 90%) |
| 23 | RUN light: 2 time flash TIMER light: 3 time flash Occurrence conditions: When an abnormal stop occurs 3 times with automatic recovery within 20 minutes after the outdoor unit's power supply was turned on RUN lamp (tens place): Flash 2 times | 3 abnormal stops within 20 min |
| 27 | RUN light: 2 time flash TIMER light: 7 time flash Error display: yes (3 times) RUN lamp (tens place): Flash 2 times | Error of outdoor fan motor (for DC motor only) |
| 28 | RUN light: 2 time flash TIMER light: 8 time flash RUN lamp (tens place): Flash 2 times TIMER lamp (ones place): Flash 8 times | Different voltage |
| 29 | RUN light: 2 time flash TIMER light: 9 time flash RUN lamp (tens place): Flash 2 times TIMER lamp (ones place): Flash 9 times | Low voltage |
| 31 | RUN light: 3 time flash TIMER light: 1 time flash RUN lamp (tens place): Flash 3 times TIMER lamp (ones place): Flash 1 time | Cooling safe current I |
| 32 | RUN light: 3 time flash TIMER light: 2 time flash RUN lamp (tens place): Flash 3 times TIMER lamp (ones place): Flash 2 times | Heating safe current I |
| 33 | RUN light: 3 time flash TIMER light: 3 time flash RUN lamp (tens place): Flash 3 times TIMER lamp (ones place): Flash 3 times | Cooling safe current II |
| 34 | RUN light: 3 time flash TIMER light: 4 time flash RUN lamp (tens place): Flash 3 times TIMER lamp (ones place): Flash 4 times | Heating safe current II |
| 35 | RUN light: 3 time flash TIMER light: 5 time flash RUN light (10's digit): 3-time flash TIMER light (1's digit): 5-time flash | Cooling high pressure control |
| 36 | RUN light: 3 time flash TIMER light: 6 time flash RUN light (10's digit): 3-time flash TIMER light (1's digit): 6-time flash | Compressor overheat 110°C |
| 37 | RUN light: 3 time flash TIMER light: 7 time flash RUN light (10's digit): 3-time flash TIMER light (1's digit): 7-time flash | High pressure eror (ball valve closed) |
| 38 | RUN light (10's digit): 3-time flash TIMER light (1's digit): 8-time flash Occurrence conditions: −55°C or lower is detected for 5 seconds continuously 3 times within 40 minutes after initial detection of this anomalous temperature. Or −55°C higher is detected for 5 seconds continuously within 20 seconds after power ON Error display: (3 times) | Outdoor air temperature sensor is abnormal |
| 39 | RUN light (10's digit): 3-time flash TIMER light (1's digit): 9-time flash Occurrence conditions: −25°C or lower is detected for 5 seconds continuously 3 times within 40 minutes after initial detection of this anomalous temperature Error display: (3 times) | Discharge pipe sensor is abnormal (anomalous stop) |
| 40 | RUN light (10's digit): 4-time flash TIMER light (1's digit): OFF Error display: (2 times) | Service valve (gas side) closed operation |
| 41 | RUN light (10's digit): 4 time flash TIMER light (1's digit): 1 time flash RUN lamp (tens place): Flash 4 times TIMER lamp (ones place): Flash 1 time | Cooling overload 1 (outdoor temp. 36~40℃) |
| 42 | RUN light (10's digit): 4 time flash TIMER light (1's digit): 2 time flash Occurrence conditions: Compressor start fails 42 times in succession and the reason for the final failure is current cut Error display: (2 times) | Current cut |
| 43 | RUN light (10's digit): 4 time flash TIMER light (1's digit): 3 time flash RUN lamp (tens place): Flash 4 times TIMER lamp (ones place): Flash 3 times | Cooling overload 2 (outdoor temp. 40~45℃) |
| 44 | RUN light (10's digit): 4 time flash TIMER light (1's digit): 4 time flash RUN lamp (tens place): Flash 4 times TIMER lamp (ones place): Flash 4 times | Heating overload 2 (outdoor temp. 12~17℃) |
| 45 | RUN light (10's digit): 4 time flash TIMER light (1's digit): 5 time flash RUN lamp (tens place): Flash 4 times TIMER lamp (ones place): Flash 5 times | Cooling overload 3 (outdoor temp. 45~℃) |
| 46 | RUN light (10's digit): 4 time flash TIMER light (1's digit): 6 time flash RUN lamp (tens place): Flash 4 times TIMER lamp (ones place): Flash 6 times | Heating overload 3 (outdoor temp. 17~℃) |
| 47 | RUN light (10's digit): 4-time flash TIMER light (1's digit): 7-time flash | Active filter voltage error |
| 48 | RUN light (10's digit): 4-time flash TIMER light (1's digit): 8-time flash Error display: (3 times) | Outdoor unit's fan motor is abnormal |
| 50 | RUN light (10's digit): 5 time flash TIMER light (1's digit): OFF Error display: ◯ (2 times) RUN lamp (tens place): Flash 5 times | 125℃ (compressor over heat) |
| 51 | RUN light (10's digit): 5-time flash TIMER light (1's digit): 1-time flash | Short circuit in the power transistor (high side) / Current cut circuit breakdown |
| 57 | RUN light (10's digit): 5-time flash TIMER light (1's digit): 7-time flash Error display: (3 times) | Refrigeration cycle system protective control |
| 58 | RUN light (10's digit): 5-time flash TIMER light (1's digit): 8-time flash | Current safe |
| 59 | RUN light (10's digit): 5-time flash TIMER light (1's digit): 9-time flash | Compressor wiring is unconnection / Voltage drop / Low speed protective control |
| 60 | RUN light (10's digit): 6 time flash TIMER light (1's digit): OFF Error display: (2 times) RUN lamp (tens place): Flash 6 times | Rotor lock |
| 61 | RUN light (10's digit): 6 time flash TIMER light (1's digit): 1 time flash RUN lamp (tens place): Flash 6 times TIMER lamp (ones place): Flash 1 time | Connection lines between the indoor and outdoor units are faulty |
| 62 | RUN light (10's digit): 6 time flash TIMER light (1's digit): 2 time flash Error display: ◯ (3 times) RUN lamp (tens place): Flash 6 times | Serial transmission error |
| 70 | RUN light (10's digit): 7 time flash TIMER light (1's digit): OFF Error display: ◯ (2 times) | Rotor lock |
| 71 | RUN lamp (tens place): Flash 7 times TIMER lamp (ones place): Flash 1 time | Rotor lock: below 16 rps |
| 72 | RUN lamp (tens place): Flash 7 times TIMER lamp (ones place): Flash 2 times | Rotor lock: above 16 rps |
| 73 | RUN lamp (tens place): Flash 7 times TIMER lamp (ones place): Flash 3 times | Poor phase position switching (U phase) |
| 74 | RUN lamp (tens place): Flash 7 times TIMER lamp (ones place): Flash 4 times | Poor phase position switching (V phase) |
| 75 | RUN lamp (tens place): Flash 7 times TIMER lamp (ones place): Flash 5 times | Poor phase position switching (W phase or not determined) |
| 76 | RUN light (10's digit): 7 time flash TIMER light (1's digit): 6 time flash Occurrence conditions: When compressor start fails 42 times in succession and the reason for the final failure is rotor lock Error display: ◯ (2 times) | Start of compressor program (within 4 sec. after phase position switching) |
| 80 | RUN light (10's digit): 8 time flash TIMER light (1's digit): OFF RUN lamp (tens place): Flash 8 times TIMER lamp (ones place): Off | Error of fan motor of indoor unit |
| 81 | RUN light (10's digit): 8 time flash TIMER light (1's digit): 1 time flash Error display: ◯ (4 times) RUN lamp (tens place): Flash 8 times | Vent-pipe sensor error (abnormal stop) |
| 82 | RUN light (10's digit): 8 time flash TIMER light (1's digit): 2 time flash RUN lamp (tens place): Flash 8 times TIMER lamp (ones place): Flash 2 times | Indoor heat exchanger sensor is abnormal (anomalous stop) |
| 83 | RUN light (10's digit): 8 time flash TIMER light (1's digit): 3 time flash RUN lamp (tens place): Flash 8 times TIMER lamp (ones place): Flash 3 times | Heat exchanger liquid pipe sensor error (abnormal stop) |
| 84 | RUN light (10's digit): 8 time flash TIMER light (1's digit): 4 time flash RUN lamp (tens place): Flash 8 times TIMER lamp (ones place): Flash 4 times | Anti-condensation control |
| 85 | RUN light (10's digit): 8 time flash TIMER light (1's digit): 5 time flash RUN lamp (tens place): Flash 8 times TIMER lamp (ones place): Flash 5 times | Anti-frost control |
| 86 | RUN light (10's digit): 8 time flash TIMER light (1's digit): 6 time flash RUN lamp (tens place): Flash 8 times TIMER lamp (ones place): Flash 6 times | High pressure control |
| 87 | RUN light (10's digit): 8 time flash TIMER light (1's digit): 7 time flash RUN lamp (tens place): Flash 8 times TIMER lamp (ones place): Flash 7 times | Compressor over heat protection control |
| 88 | RUN light (10's digit): 8 time flash TIMER light (1's digit): 8 time flash | Refrigeration cycle system protective control |
| E1 | Receiver Unit Red LED: - Indoor Circuit Board Red LED: Stays Off Indoor Circuit Board Green LED: Keeps Flashing Outdoor Circuit Board Red LED: Stays Off | Indoor circuit board fault |
| E2 | Receiver Unit Red LED: - Indoor Circuit Board Red LED: Stays Off Indoor Circuit Board Green LED: Keeps Flashing Outdoor Circuit Board Red LED: Stays Off | Indoor unit address: duplication of indoor unit number when addressing with the remote… |
| E3 | Receiver Unit Red LED: - Indoor Circuit Board Red LED: Flashes twice Indoor Circuit Board Green LED: Keeps Flashing Outdoor Circuit Board Red LED: Stays Off | Outdoor unit power |
| E4 | Receiver Unit Red LED: Keeps Flashing Indoor Circuit Board Red LED: Flashes Once Indoor Circuit Board Green LED: Keeps Flashing Outdoor Circuit Board Red LED: Stays Off | Incorrect address |
| E5 | Receiver Unit Red LED: Keeps Flashing Indoor Circuit Board Red LED: Flashes Twice Indoor Circuit Board Green LED: Keeps Flashing Outdoor Circuit Board Red LED: Flashes Twice | Interconnecting cable |
| E6 | Receiver Unit Red LED: - Indoor Circuit Board Red LED: Flashes Once Indoor Circuit Board Green LED: Keeps Flashing Outdoor Circuit Board Red LED: Stays Off | Indoor coil sensor |
| E7 | Receiver Unit Red LED: - Indoor Circuit Board Red LED: Flashes Once Indoor Circuit Board Green LED: Keeps Flashing Outdoor Circuit Board Red LED: Stays Off | Indoor return air sensor |
| E8 | Receiver unit Red LED: Keeps Flashing Indoor circuit board Red LED: Flashes Once Indoor circuit board Green LED: Keeps Flashing Outdoor circuit board Red LED: Stays Off | Abnormality of the heat exchanger sensor input |
| E9 | Receiver unit Red LED: - Indoor circuit board Red LED: Flashes Once Indoor circuit board Green LED: Keeps Flashing Outdoor circuit board Red LED: Stays Off | Drain motor [DM] failure (drain motor open circuit or the drain motor is disconnected from… |
| E10 | Receiver unit Red LED: - Indoor circuit board Red LED: Stays Off Indoor circuit board Green LED: Keeps Flashing Outdoor circuit board Red LED: Stays Off | 17 or more indoor units are connected to one remote controller (maximum permitted: 16… |
| E11 | Receiver unit Red LED: - Indoor circuit board Red LED: Stays Off Indoor circuit board Green LED: Keeps Flashing Outdoor circuit board Red LED: Stays Off | More than one indoor unit is connected to a remote controller while trying to address the… |
| E12 | Indoor circuit board Red LED: Flashes once Indoor circuit board Green LED: Keeps Flashing Outdoor circuit board Red LED: Stays Off Outdoor circuit board Green LED: Keeps Flashing | While trying to auto address, one or more of the units (either indoor or outdoor) is not… |
| E14 | Receiver unit Red LED: - Indoor circuit board Red LED: - Indoor circuit board Green LED: - Outdoor circuit board Red LED: - | Incorrect setting of SW2 on indoor unit PCB when setting up a master / slave system.… |
| E16 | Flashes Twice column: Stays off Keeps Flashing column: Keeps Flashing Flashes Twice (2nd) column: Stays off Keeps Flashing (2nd) column: Keeps Flashing | Faulty indoor fan motor |
| E28 | Receiver unit Red LED: - Indoor circuit board Red LED: Stays Off Indoor circuit board Green LED: Keeps Flashing Outdoor circuit board Red LED: Stays Off | Failure of the sensor within the remote controller |
| E30 | Receiver unit Red LED: - Indoor circuit board Red LED: Stays Off Indoor circuit board Green LED: Keeps Flashing Outdoor circuit board Red LED: Flashes once | Indoor/outdoor unit connected error |
| E31 | LED 1: - LED 2: Stays Off LED 3: Keeps Flashing LED 4: 8 Time Flash | Outdoor unit address fault |
| E32 | LED 1: - LED 2: Stays Off LED 3: Keeps Flashing LED 4: Flashes Once | Outdoor unit power supply phase fault |
| E33 | LED 1: Keeps Flashing LED 2: Stays Off LED 3: Keeps Flashing LED 4: Flashes Once | Compressor current abnormally high or open phase |
| E34 | LED 1: Keeps Flashing LED 2: Stays Off LED 3: Keeps Flashing LED 4: Flashes Twice | Compressor current abnormally low (or no current) on L3, or open phase on L3 |
| E35 | LED 1: - LED 2: Stays Off LED 3: Keeps Flashing LED 4: Flashes Once | Compressor discharge gas temperature abnormally high |
| E36 | LED 1: - LED 2: Stays Off LED 3: Keeps Flashing LED 4: Flashes once | Compressor discharge temperature abnormally high |
| E37 | LED 1: - LED 2: Stays Off LED 3: Keeps Flashing LED 4: Flashes once | Outdoor heat exchanger sensor [ThOR] defective (open circuit) or poor sensor connection |
| E38 | Display 3: Keeps Flashing Display 4: Keeps Flashing Display 5: Keeps Flashing Display 1: Keeps Flashing (red row) | Outdoor air sensor |
| E39 | Display 1: Keeps Flashing Display 3: Keeps Flashing Display 4: Flashes Once Display 5: Keeps Flashing | Compressor discharge temperature sensor |
| E40 | Display 3: Keeps Flashing Display 4: Flashes Once Display 5: Keeps Flashing Display 4: Flashes 3 Times | High pressure switch |
| E41 | Display 3: Keeps Flashing Display 4: Flashes once Display 5: Keeps Flashing LED 1: Stays Off | Inverter power transistor |
| E42 | Display 3: Keeps Flashing Display 4: Flashes once Display 5: Keeps Flashing LED 1: Stays Off | Compressor current |
| E43 | Display 3: Keeps Flashing Display 4: Flashes once Display 5: Keeps Flashing LED 1: Stays Off | Number of indoor units |
| E45 | Display 3: Keeps Flashing Display 4: Flashes once Display 5: Keeps Flashing LED 1: Stays Off | Inverter wiring |
| E46 | Display 3: Keeps Flashing Display 4: Flashes once Display 5: Keeps Flashing LED 1: Stays Off | Address setting |
| E47 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes once LED 4: Keeps Flashing | Inverter over voltage |
| E48 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes once LED 4: Keeps Flashing | DC Outdoor Fan motor fault |
| E49 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes once LED 4: Keeps Flashing | Low voltage detected |
| E51 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes once LED 4: Keeps Flashing | Inverter PCB fault |
| E53 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes once LED 4: Keeps Flashing | Suction pipe thermistor (Tho-S) disconnected |
| E54 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes once LED 4: Keeps Flashing | Low pressure sensor (PSL) disconnected/output error |
| E55 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes once LED 4: Keeps Flashing | Compressor under dome thermistor disconnected |
| E56 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes once LED 4: Keeps Flashing | Power transistor thermistor faulty or disconnected (FDCVA151-251) |
| E57 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes once LED 4: Keeps Flashing | Indoor heat exchanger sensor |
| E58 | lamp_2: Keeps Flashing lamp_3: 1 to 5 times flash lamp_4: Keeps Flashing lamp_col_2: Keeps Flashing | Compressor start-up error |
| E59 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: 1 to 5 times flash LED 4: Keeps Flashing | Compressor start-up error |
| E60 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes once or twice LED 4: Keeps Flashing | Compressor position detection error |
| E63 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes once LED 4: Keeps Flashing | Emergency stop of indoor unit |
| E37-1 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: One time Flash LED 4: Keeps Flashing | Outdoor heat exch thermistor failure (Tho-R1) |
| E37-2 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Two time Flash LED 4: Keeps Flashing | Outdoor heat exch thermistor failure (Tho-R2) |
| E37-3 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Three time Flash LED 4: Keeps Flashing | Outdoor heat exch thermistor failure (Tho-R3) |
| E37-4 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Four time Flash LED 4: Keeps Flashing | Outdoor heat exch thermistor failure (Tho-R4) |
| E37-5 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Five time Flash LED 4: Keeps Flashing | Outdoor heat exch thermistor failure (Tho-SC) |
| E37-6 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Six time Flash LED 4: Keeps Flashing | Outdoor heat exch thermistor failure (Tho-H) |
| E54-1 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes once LED 4: Keeps Flashing | Low pressure sensor (PSL) disconnection/output error |
| E54-2 | LED 1: Stays Off LED 2: Keeps Flashing LED 3: Flashes twice LED 4: Keeps Flashing | High pressure sensor (PSH) disconnection/output error |
| NO INDICATION | Receiver Unit Red LED: - Indoor Circuit Board Red LED: Stays Off Indoor Circuit Board Green LED: Stays Off Outdoor Circuit Board Red LED: Stays Off | Mains power: no mains power detected or T phase wire open |
| LED:RUN=1-TIME FLASH,TIMER=ON | Indoor RUN light: 1-time flash Indoor TIMER light: ON Display (flashing) condition: When a heat exchanger temperature 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.) | Heat exchanger temperature sensor 1 error |
| LED:RUN=2-TIME FLASH,TIMER=ON | Indoor RUN light: 2-time flash Indoor TIMER light: ON Display (flashing) condition: When 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.) | Room air temperature sensor error |
| LED:RUN=3-TIME FLASH,TIMER=ON | Indoor RUN light: 3-time flash Indoor TIMER light: ON Display (flashing) condition: When a heat exchanger temperature sensor 2 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.) | Heat exchanger temperature sensor 2 error |
| LED:RUN=4-TIME FLASH,TIMER=ON | Indoor RUN light: 4-time flash Indoor TIMER light: ON Display (flashing) condition: When normal data cannot be received from wireless LAN interface for two minutes continuously | Trouble of wireless LAN interface |
| LCD FLASHES CONTINUOUSLY OR OFF | Indoor Red LED: Stays Off Indoor Green LED: Keeps Flashing Outdoor Red LED: Flashes Twice Outdoor Green LED: Keeps Flashing | Open circuit or poor indoor/outdoor interconnecting wiring |
Guides
- Air conditioner repair, stage by stage: from the call to the hand-over
The eight stages of an air conditioner repair: symptoms, safety, reading the code, narrowing down, measuring, repairing, test run, hand-over.