Knowing how to spot and understand a Mitsubishi error code is a critical step in fixing common issues that usually affect the brand’s lineup of aircons. Since Mitsubishi AC units are equipped with an advanced self-diagnostics system, owners are always notified when something’s wrong with the machine.
But in order to get to the cause of the problem, you will need to familiarize yourself with the brand’s long list of error codes. In this guide, we’ll show you the complete Mitsubishi aircon error codes and what they usually mean for your unit.
List of Mitsubishi Aircon Error Codes
| Code | Possible Cause |
|---|---|
| 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 |
| 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 superheat due to low discharge temperature |
| U9 | UH Abnormality such as overvoltage or voltage shortage and abnormal synchronous signal to main circuit/ Current sensor error. |
Mitsubishi Mr. Slim A-control Error Codes
| Code | Possible Cause |
|---|---|
| EA | Error detail Miswiring of indoor/outdoor unit. exceed the number of indoor unit connection. |
| EB | Error detail Miswiring of indoor/outdoor unit. (mis-wiring disconnection) |
| EC | Error detail Start-up time over |
| E6 | Error detail Indoor/outdoor unit transmission error (signal receiving error) |
| E7 | Error detail Indoor/outdoor unit transmission error (transmitting error) |
| E8 | Error detail Indoor/outdoor unit transmission error (signal receiving error) |
| E9 | Error detail Indoor/outdoor unit transmission error (transmitting error) |
| E0 | Error detail Remote control transmission error (signal receiving error) |
| E3 | Error detail Remote control transmission error (transmitting error) |
| E4 | Error detail Remote control transmission error (signal receiving error) |
| E5 | Error detail Remote control transmission error (transmitting error) |
| EF | Error detail M-NET transmission error |
| ED | Error detail Serial transmission error |
| P1 | Error detail Abnormality of room temperature thermistor (TH1) |
| P2 | Error detail Abnormality of pipe temperature thermistor/liquid (TH2) |
| P4 | Error detail Abnormality of drain sensor (DS) |
| P5 | Error detail Malfunction of drain-up machine |
| P6 | Error detail Freezing/overheating protection detect |
| P8 | Error detail Abnormality of pipe temperature |
| P9 | Error detail Anormality of pipe temperature thermistor/condenser/evaporator (TH5) |
| F1 | Error detail Reverse phase detection |
| F2 | Error detail L3 open phase detection |
| F3 | Error detail 63L connector open |
| F4 | Error detail 49C connector open |
| F9 | Error detail Connector 2 or more open |
| FA | Error detail L2-phased open phase or 51CM connector open |
| F7 | Error detail Reverse phase detection circuit (p.c.board) fault |
| F8 | Error detail Input circuit fault |
| U2 | Error detail Abnormal high discharging temperature |
| U2 | Error detail Inner thermostat (49C) operation |
| U1 | Error detail Abnormal high pressure (high pressure swicth 63H worked) |
| U1 | Error detail Direct cut operation |
| UE | Error detail High pressure error (ball valve closed) |
| UL | Error detail Abnormal low pressure |
| UD | Error detail Overheat protection |
| U6 | Error detail Compressor over current (overload) cut off |
| UA | Error detail Compressor over current (terminal relay operation) |
| UF | Error detail Compressor over current (start-up locked) cut off |
| UF | Error detail Compressor over current (operating locked) cut off |
| UH | Error detail Current sensor error |
| U3 | Error detail Discharge thermistor short/open |
| U4 | Error detail Outdoor thermistor short/open |
| Mr.Slim K-control | Display of remote controller |
| LED E0 | Diagnosis of malfunction Transmitting/receiving signal error |
| LED P1 | Diagnosis of malfunction Intake air sensor abnormal |
| LED P2 | Diagnosis of malfunction Pipe sensor abnormal |
| LED P4 | Diagnosis of malfunction Drain sensor abnormal |
| LED P5 | Diagnosis of malfunction Malfunctioning of the drain overflow protecting mechanism |
| LED P6 | Diagnosis of malfunction Abnormality of the coil frost/overheating protection mode |
| LED P3 | Diagnosis of malfunction System error (transmitting/receiving signal) |
| LED P7 | Diagnosis of malfunction System error (address) |
| LED P8 | Diagnosis of malfunction Outdoor unit malfunction |
| Mr.Slim K-control | PUH-EK Outdoor unit |
| LED ON | Operation status |
| 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 |
Mitsubishi Mr. Slim Error Codes (Membrane Type Remote Controllers)
| Code | Possible Cause |
|---|---|
| EO | During individual unit control: Bad contact of transmission wire Signal transmitting/receiving circuits are abnormal |
| P1 | Bad contact of thermistor Damaged thermistor |
| P2 | Bad contact of thermistor Damaged thermistor |
| P3 | Bad contact of transmission wire Signal transmitting/receiving circuits are abnormal Wrong operation due to noise wave emitted by other appliances |
| P4 | Bad contact of transmission wire Damaged thermistor |
| P5 | Malfunction of drain pump Damaged drain sensor |
| P6 | Short cycle of air cycle Dirty air filter Damaged fan Abnormal refrigerant |
| P7 | Wrong address-setting Signal transmitting/receiving circuit of remote controller is abnormal Wrong SW6-setting |
| P8 | Wrong wiring of indoor/outdoor connecting wire Reversed phase Protection device is working Damaged outdoor coil thermistor |