If faults are occurring on your Mitsubishi Heavy air conditioning system, it is very important to discover it quickly. Error codes are a great way to find out the initial problem. Error codes are usually displayed on your remote.
| E1 | Remote control communication error |
| E2 | Duplicate indoor unit address |
| E3 | Outdoor unit signal line error |
| E5 | Communication error during operation |
| E6 | Internal heat exchanger temperature thermistor abnormality (Thi-R) |
| E7 | Internal return air temperature thermistor abnormality (Thi-A) |
| E9 | Unloading problem |
| E10 | Excessive number of indoor units with remote control |
| E12 | Address setting error with mixed setting method |
| E16 | Internal fan motor abnormality (FDT series) |
| E16 | Internal fan motor abnormality (FDK series) |
| E19 | Indoor unit operation control unload motor control mode abnormality |
| E28 | Remote control temperature thermistor abnormality (ThC) |
| E30 | Incompatible connection of indoor and outdoor unit |
| E31 | Replicated outdoor unit address no. |
| E32 | Open L3 phase in the primary side power supply |
| E36 | Drain pipe temperature error (Tho-D1, D2) |
| E36 | Liquid overflow abnormality |
| E37 | Abnormalities of external heat exchanger temperature thermistor (Tho-R) and sub-cooling coil temperature thermistor (Tho-SC, -H) |
| E38 | Outdoor temperature thermistor abnormality (Tho-A) |
| E39 | Drain pipe temperature thermistor abnormality (Tho-D1, D2) |
| E40 | High pressure abnormality (63H1-1, 2 active) |
| E41 (E51) | Power transistor overheating |
| E42 | Power failure (CM1, 2) |
| E43 | Over-connected indoor units, over-total capacity connection |
| E45 | Communication error between inverter PCB and external control PCB |
| E46 | Mixed address setting methods available on the same network |
| E48 | External DC fan motor abnormality |
| E49 | Low pressure abnormality |
| E53/E55 | Suction pipe temperature thermistor abnormality (Tho-S), Under-dome temperature thermistor abnormality (Tho-C1, C2) |
| E54 | High pressure sensor (TSH) Low pressure sensor (PSL) abnormality |
| E56 | Power transistor temperature thermistor abnormality (Tho-P1, Tho-P2) |
| E58 | Abnormal compressor with loss of synchronization |
| E59 | Compressor start failure (CM1, 2) |
| E60 | Rotor position detection failure (CM1, 2) |
| E61 | Communication error between main unit and backup units System error |
| E63 | Emergency stop |
Written by
Ali Elm
Ali is the Head of Operations at Be Cool Refrigeration with over a decade of hands-on experience in HVAC and commercial refrigeration. He oversees every installation, repair, and maintenance project, making sure the work meets the highest standards. Ali holds full F-Gas certification and has worked across residential, commercial, and industrial refrigeration systems throughout London and the South East. When he is not on site, he writes these guides to help business owners and homeowners understand their cooling systems better.