Mitsubish Electric Error Codes

Mitsubishi Electric Error Codes List:

City Multi Systems:

• 403: Communications fault between boards. Check the inverter error details to identify the specific boards involved, and inspect the transformer, bus voltage, and interconnecting cables. 

• 900: The Lossnay unit is in a test run. ​

• 1102: Compressor discharge temperature is too high (exceeded 110°C). This may indicate a refrigerant shortage or a discharge thermistor issue. ​

• 1301: Low pressure fault detected before starting. Inspect thermistors (TH2, TH3, TH4), refrigerant charge, indoor fan, heat exchanger, and filters. ​

Mr. Slim P Series (A-Control):

• A0: Green LED – 2 flashes, Red LED – 5 flashes, Controller 6600: Lossnay units have the same address. Change the addresses and reset the unit. ​

• A2: Green LED – 2 flashes, Red LED – 5 flashes, Controller 6602: Transmission processor hardware error. Check communications wiring and the Lossnay board for faults. ​

• A6: Green LED – 2 flashes, Red LED – 5 flashes, Controller 6606: Communication error with the communication processor. Check the M-Net voltage. ​

• E0: Green LED – 2 flashes, Red LED – 3 flashes: Communication error with the remote controller. Verify wiring, voltage, and connections. If multiple systems are connected, check the master/slave settings. ​

Mr. Slim P Series (K-Control):

• E0: System transmission error. There could be a communication fault between the indoor and remote controllers. ​

• P4: Drain sensor fault. Check the drain sensor resistance and connections. ​

• P5: Drain fault. High levels of condensate detected; inspect for blockages in the drain, tray, or possible pump failure. ​

• P7: System error due to an address setting fault. ​

Additional Common Error Codes:

• P1: Intake sensor error. ​

• P2 – P9: Pipe (liquid or 2-phase) sensor error. ​

• E6 – E7: Indoor/outdoor unit communication 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.). ​

• E1 – E3: Remote controller transmission error. ​

• E9: Indoor/outdoor unit communication error (transmitting error) in the outdoor unit. ​

• UP: Compressor overcurrent interruption. ​

• U3 – U4: Open/short circuit of outdoor unit thermistors. ​

• UF: Compressor overcurrent interruption (when compressor is locked). ​

• U2: Abnormal high discharging temperature or insufficient refrigerant. ​

• U1 – Ud: Abnormal high pressure or overheating safeguard operation. ​

• U5: Abnormal temperature of heat sink. ​

• U8: Outdoor unit fan safeguard stop. ​

• U6: Compressor overcurrent interruption