Mitsubishi Electric P1
Abnormality or fault in the indoor room temperature thermistor (RT1).
Mitsubishi Electric P2 – P9
Liquid or 2-phase refrigerant pipe temperature sensor error.
Mitsubishi Electric E6 – E7
Communication signal transmission error between indoor and outdoor units.
Mitsubishi Electric P4
Abnormality or sensing failure detected in the indoor condensate drain sensor.
Mitsubishi Electric P5
Malfunction or failure in the indoor condensate drain pump mechanism.
Mitsubishi Electric PA
Forced compressor operation error or abnormality.
Mitsubishi Electric P6
Indoor coil frost protection mechanism is actively triggered.
Mitsubishi Electric EE
General transmission line communication failure between indoor and outdoor units.
Mitsubishi Electric P8
General operational abnormality or fault detected in the outdoor unit.
Mitsubishi Electric E4
Remote controller signal receiving transmission error at the indoor unit.
Mitsubishi Electric Fb
Indoor unit control system hardware or memory error.
Mitsubishi Electric E0 – E3
Communication signal transmission error at the remote controller.
Mitsubishi Electric E1 – E2
Internal control board error within the remote controller.
Mitsubishi Electric E9
Transmission signal sending error from outdoor unit to indoor unit.
Mitsubishi Electric UP
Compressor operation interrupted due to an overcurrent detection.
Mitsubishi Electric U3 – U4
Open or short circuit fault detected on outdoor unit thermistors.
Mitsubishi Electric UF
Compressor stalled or seized with locked-rotor current levels detected.
Mitsubishi Electric U2
Compressor internal thermal switch (49C) safety trip triggered.
Mitsubishi Electric U1- Ud
Abnormal high pressure or compressor overheating safeguard operation.
Mitsubishi Electric U5
Abnormal or excessive temperature detected on the inverter heatsink.
Mitsubishi Electric U8
Outdoor unit fan motor operation stopped by safeguard protection.
Mitsubishi Electric U6
Compressor shut down due to sustained overcurrent overload cut-off.
Mitsubishi Electric U7
Abnormally low discharge superheat risking liquid refrigerant slugging.
Mitsubishi Electric U9 – UH
Main circuit voltage anomaly, synchronous signal error, or current sensor fault.
Mitsubishi Electric EA
Mis-wiring between indoor/outdoor units or exceeded indoor unit connection count.
Mitsubishi Electric Eb
Indoor/outdoor unit mis-wiring or communication wire disconnection detected.
Mitsubishi Electric EC
Outdoor unit startup time limit exceeded without establishing normal operation.
Mitsubishi Electric E6
Indoor unit failed to receive communication signals from the outdoor unit.
Mitsubishi Electric E7
Indoor unit failed to transmit communication signals to the outdoor unit.
Mitsubishi Electric E8
Outdoor unit failed to receive communication signals from the indoor unit.
Mitsubishi Electric E0
Remote controller failed to receive signal from indoor unit.
Mitsubishi Electric E3
Remote controller failed to transmit signal to indoor unit.
Mitsubishi Electric E5
Indoor unit failed to transmit remote controller communication signals.
Mitsubishi Electric EF
M-NET centralized control bus signal transmission error.
Mitsubishi Electric Ed
Serial communication signal transmission error detected at the outdoor unit.
Mitsubishi Electric P2
Abnormality or fault in the indoor coil thermistor (RT2).
Mitsubishi Electric P9
Abnormality in indoor pipe temperature thermistor TH5.
Mitsubishi Electric F1
Reverse phase sequence detected on incoming three-phase AC power line.
Mitsubishi Electric F2
Open phase condition detected on power line L3.
Mitsubishi Electric F3
Low-pressure switch (63L) wiring connector open or disconnected.
Mitsubishi Electric F4
Compressor internal thermal switch (49C) wiring connector open.
Mitsubishi Electric F9
Multiple safety device wiring connectors (2 or more) detected open.
Mitsubishi Electric FA
Open phase on L2 power leg or 51CM overcurrent relay connector.
Mitsubishi Electric F7
Hardware fault in the outdoor PCB reverse phase detection circuit.
Mitsubishi Electric F8
Input sensing circuit fault detected on the outdoor main control board.
Mitsubishi Electric U1
High-pressure switch (63H) opened hardwired safety cutout circuit.
Mitsubishi Electric UE
High pressure trip caused by closed refrigerant service ball valve.
Mitsubishi Electric UL
System compressor or component overheating safeguard protection active.
Mitsubishi Electric Ud
Overheating safeguard protection triggered on the outdoor unit.
Mitsubishi Electric UA
Compressor overcurrent shutdown triggered by terminal relay operation.
Mitsubishi Electric UH
Current sensor circuit abnormality detected on the outdoor unit.
Mitsubishi Electric U3
Discharge pipe temperature thermistor open or short circuit fault.
Mitsubishi Electric U4
Outdoor ambient or pipe thermistor open or short circuit fault.
Mitsubishi Electric LED E0
Indoor unit LED blink diagnostic for communication signal error.
Mitsubishi Electric LED P1
Indoor unit operation LED blink code for room air thermistor RT1 fault.
Mitsubishi Electric LED P2
Indoor unit operation LED blink code for liquid pipe thermistor fault.
Mitsubishi Electric LED P4
Indoor unit operation LED blink code for condensate drain sensor fault.
Mitsubishi Electric LED P5
Indoor unit operation LED blink code for drain overflow protection fault.
Mitsubishi Electric LED P6
Indoor unit operation LED blink code for coil frost/overheat mode.
Mitsubishi Electric LED P3
Indoor unit operation LED blink code for signal transmission error.
Mitsubishi Electric LED P7
Indoor unit operation LED blink code for system address configuration error.
Mitsubishi Electric LED E8
Indoor LED blink diagnostic signaling an outdoor unit malfunction.
Mitsubishi Electric LED LD1 (Flash)
Outdoor board LED flash diagnostic for power reverse phase detection.
Mitsubishi Electric LED LD2 (Flash)
Outdoor board LED flash diagnostic for missing open power phase leg.
Mitsubishi Electric LED LD3 (Flash)
Outdoor board LED flash diagnostic for pipe thermistor short or open.
Mitsubishi Electric LED LD4 (Flash)
Outdoor board LED flash diagnostic for high-pressure switch (63H2) trip.
Mitsubishi Electric LED LD5 (Flash)
Outdoor board LED flash diagnostic for overcurrent relay (51CM) trip.
Mitsubishi Electric LED LD6 (Flash)
Outdoor board LED flash diagnostic for thermal switch (26C) cutout.
Mitsubishi Electric LED LD7 (Flash)
Outdoor board LED flash diagnostic for thermistor TH3 overheat protection.
Mitsubishi Electric LED LD8 (Flash)
Outdoor board LED flash diagnostic for detective input circuit signal.
Mitsubishi Electric EO
Indoor controller does not respond to remote controller signal transmission.
Mitsubishi Electric P3
Remote controller does not respond to indoor controller signal transmission.
Mitsubishi Electric P7
General system operational error detected.