Trouble shooting for Mitsubishi Air Conditioning error codes based on the results of self-diagnostics.
The modern air conditioners from Mitsubishi have a very developed self-diagnostics system, and when the control system detects an error, it blocks the operation of the entire device and displays a cause of faulty condition.
The control system of the Mitsubishi air conditioners reports that an error occurred by blinking of a light-emitting diode on the surface of the internal (or external) unit. When a particular error of an air conditioner is detected, light-emitting diodes blink in a certain order, which corresponds with a particular error. If the control system of an air conditioner detects more than one error, the error with the highest priority is displayed first and then all the following errors are displayed
After completing installation and the wiring and piping of the indoor and outdoor units, check for refrigerant leakage, looseness in the power supply or control wiring, wrong polarity, and no disconnection of one phase in the supply.
The following is a list of Mitsubishi Air Conditioning error codes.
- P1 Intake sensor error
- P2 P9 Pipe (Liquid or 2-phase pipe) sensor error
- E6 E7 Indoor/outdoor unit communication error
- P4 Drain sensor error
- P5 Drain pump error
- PA Forced compressor error
- P6 Freezing/Overheating safeguard operation
- EE Communication error between indoor and outdoor units
- P8 Pipe temperature error
- E4 Remote controller signal receiving error
- Fb Indoor unit control system error (memory error, etc.)
- E0 E3 Remote controller transmission error
- E1 E2 Remote controller control board error
For details, check the LED display of the outdoor controller board.
- E9 Indoor/outdoor unit communication error (Transmitting error) (Outdoor unit)
- UP Compressor overcurrent interruption
- U3, U4 Open/short of outdoor unit thermistors
- UF Compressor overcurrent interruption (When compressor locked)
- U2 Abnormal high discharging temperature/49C worked/insufficient refrigerant
- U1 Ud Abnormal high pressure (63H worked)/Overheating safeguard operation
- U5 Abnormal temperature of heat sink
- U8 Outdoor unit fan safeguard stop
- U6 Compressor overcurrent interruption/Abnormal of power module
- U7 Abnormality of super heat due to low discharge temperature
- U9 UH Abnormality such as overvoltage or voltage shortage and abnormal synchronous signal to main circuit/ Current sensor error.
Mr.Slim A-control error code list
Display of remote controller
- Code EA
Error detail Mis-wiring of indoor/outdoor unit. exceed the number of indoor unit connection.
Inspected unit Outdoor. - Code Eb
Error detail Mis-wiring of indoor/outdoor unit. (mis-wiring disconnection)
Inspected unit Outdoor. - Code EC
Error detail Start-up time over
Inspected unit Outdoor. - Code E6
Error detail Indoor/outdoor unit transmission error (signal receiving error).
Inspected unit Indoor. - Code E7
Error detail Indoor/outdoor unit transmission error (transmitting error).
Inspected unit Indoor. - Code E8
Error detail Indoor/outdoor unit transmission error (signal receiving error).
Inspected unit Outdoor. - Code E9
Error detail Indoor/outdoor unit transmission error (transmitting error).
Inspected unit Outdoor. - Code E0 Error detail Remote control transmission error (signal receiving error)
Inspected unit Remote control - Code E3
Error detail Remote control transmission error (transmitting error)
Inspected unit Remote control. - Code E4
Error detail Remote control transmission error (signal receiving error)
Inspected unit Indoor. - Code E5
Error detail Remote control transmission error (transmitting error)
Inspected unit Indoor. - Code EF
Error detail M-NET transmission error
Inspected unit Indoor and outdoor. - Code Ed
Error detail Serial transmission error
Inspected unit Outdoor. - Code P1
Error detail Abnolmality of room temperature thermistor (TH1).
Inspected unit Indoor. - Code P2
Error detail Abnormality of pipe temperature themistor/liquid (TH2).
Inspected unit Indoor. - Code P4
Error detail Abnomarlity of drain sensor (DS)
Inspected unit Indoor. - Code P5
Error detail Malfunction of drain-up machine.
Inspected unit Indoor. - Code P6
Error detail Freezing/overheating protection detect.
Inspected unit Indoor. - Code P8
Error detail Abnormality of pipe temperature.
Inspected unit Indoor. - Code P9
Error detail Anormality of pipe temperature thermistor/condenser/evaporator (TH5)
Inspected unit Indoor. - Code F1
Error detail Reverse phase detection. - Code F2
Error detail L3 open phase detection. - Code F3
Error detail 63L connector open. - Code F4
Error detail 49C connector open. - Code F9
Error detail Connector 2 or more open. - Code FA
Error detail L2-phased open phase or 51CM connector open. - Code F7
Error detail Reverse phase detection circuit (p.c.board) fault. - Code F8
Error detail Input circuit fault. - Code U2
Error detail Abnormal high discharging temperature. - Code U2
Error detail Inner thermostat (49C) operation. - Code U1
Error detail Abnormal high pressure (high pressure swicth 63H worked) - Code U1
Error detail Direct cut operation. - Code UE
Error detail High pressure error (ball valve closed) - Code UL
Error detail Abnormal low pressure. - Code Ud
Error detail Over heat protection - Code U6
Error detail Compressor over current (overload) cut off. - Code UA
Error detail Compressor over current (terminal relay operation). - Code UF
Error detail Compressor over current (start-up locked) cut off. - Code UF
Error detail Compressor over current (operating locked) cut off. - Code UH
Error detail Current sensor error. - Code U3
Error detail Discharge thermistor short/open. - Code U4
Error detail Outdoor thermistor short/open. - Mr.Slim K-control
Display of remote controller - LED E0
Diagnosis of malfunction Transmitting/receiving signal error.
Inspected unit Indoor. - LED P1
Diagnosis of malfunction Intake air sensor abnormal.
Inspected unit Indoor. - LED P2
Diagnosis of malfunction Pipe sensor abnormal.
Inspected unit Indoor. - LED P4
Diagnosis of malfunction Drain sensor abnormal.
Inspected unit Indoor. - LED P5
Diagnosis of malfunction Malfunctioning of the drain overflow protecting mechanism.
Inspected unit Indoor. - LED P6
Diagnosis of malfunction Abnomality of the coil frost/overheating protection mode.
Inspected unit Indoor. - LED P3
Diagnosis of malfunction System error (transmitting/receiving signal).
Inspected unit Indoor. - LED P7
Diagnosis of malfunction System error (address)
Inspected unit Indoor. - LED P8
Diagnosis of malfunction Outdoor unit malfunction
Inspected unit Outdoor. - Mr.Slim K-control PUH-EK
Outdoor unit - LED ON = Operation status
LED Flash = Check code diplay - 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 swicth (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 swicth (26C) operation. - LED LD7
LED ON Bypass valve ON
LED Flash Thermistor (TH3) overheat protection. - LED LD8
LED ON Crankcase heater ON
LED Flash Devective input.
Mitsubishi Mr. Slim Error Codes – Membrane type remote controllers
| Check code | Diagnosis of malfunction | Cause | Check points |
|---|---|---|---|
| EO | Signal transmitting/receiving error(Indoor controller does not respond to remote controller signal) | During individual unit control1) Bad contact of transmission wire2) Signal transmitting/receiving circuit is abnormal. | 1) Check the transmission wire.2) Check with another remote controller. If “EO” is still indicated, replace the indoor controller board.If other check code appears. replace the original remote controller. |
| P1 | Abnormality of room temperature thermistor (RT1) | 1) Bad contact of thermistor2) Damaged thermistor | 1) Check the thermistor.2) Measure the resistance of the thermistor.Normal resistance should be as follows.32°F····15kΩ 86°F·····4.3kΩ50°F······9.6kΩ 104°F·····3.0kΩ68°F······6.3kΩIf the resistance is normal, replace the indoor controller board. |
| P2 | Abnormality of indoor coil thermistor (RT2) | 1) Bad contact of thermistor2) Damaged thermistor | 1) Check the thermistor.2) Measure the resistance of the thermistor.Normal resistance should be as follows.32°F····15kΩ 86°F·····4.3kΩ50°F······9.6kΩ 104°F·····3.0kΩ68°F······6.3kΩIf the resistance is normal, replace the indoor controller board. |
| P3 | Signal transmission error(Remote controller does not respond to indoor controller signal) | 1) Bad contact of transmission wire2) Signal transmitting/receiving circuit is abnormal.3) Wrong operation due to noisewave emitted by other appliances | 1) Check the transmission wire.2) Check with another remote controller.If “P3” is still indicated, replace the indoor board.If other check code appears, replace the original remote controller.3) Short-circuit between 1 and ➁ of CN40 and attach CN40 to the following units.● Second unit in twin control● Second and third units in triple control● Sub units in group control |
| P4 | Abnormality of drain sensor | 1) Bad contact of transmission wire2) Damaged thermistor | 1) Check the connector.2) Measure the resistance of the thermistor ➃ – ➄.As for the normal resistance, refer to the case of P1.If the resistance is normal, replace the indoor controller board. |
| P5 | Malfunction of drain pump | 1) Malfunction of drain pump2) Damaged drain sensor | 1) Check the drain pump.2) ● Check the drain sensor.● Check the drain sensor heater. Normal resistance should be 82Ω.If the resistance is normal, replace the indoor controller board. |
| P6 | Coil frost protection is working. | 1) Short cycle of air cycle2) Dirty air filter3) Damaged fan4) Abnormal refrigerant | 1) Clear obstructions from the air cycle.2) Clean the air filter3) Check the fan.4) Check the refrigerant temperature. |
| P7 | System error | 1) Wrong address-setting2) Signal transmitting/receiving circuit of remote controller is abnormal.3) Wrong SW6-setting | 1) Check the address-setting.2) Check with another remote controller. If check code other than “P7” appears, replace the original remote controller.3) Check SW6 setting. |
| P8 | Abnormality in outdoor unit | 1) Wrong wiring of indoor/outdoor connecting wire2) Reversed phase3) Protection device is working4) Damaged outdoor coil thermistor | 1) Check the indoor/outdoor connecting wire.2) Change the connection of electric wiring.3) Check the protection device.4) Measure the resistance of the outdoor coil thermistor. If the resistance is normal, replace the outdoor controller board. |
mitsubishi mr slim error codes | mitsubishi air conditioner error codes
