Mitsubishi MR. Slim P Series A air conditioner fault codes

In order to minimize the risk of equipment failure, it is enough to carry out timely maintenance –approximately every month. But if the air conditioner has already broken or does not work correctly, use the tips from the table below to fix the problem.

A02 flash 5 flash6600Duplicate address - Lossnay units attached with the same address -
change ad dresses and reset the units power
A22 flash 5 flash6602Hardware error of transmission processor (Lossnay) - check comms wiring,
and for possible Lossnay board fault
A32 flash 5 flash6603Line busy no data could be transmitted for 8 minutes - check A- M-Net
connections (TB7 and TB3)
A62 flash 5 flash6606Communication error with communication processor - Lossnay address not
transmitted - check M-Net voltage
A72 flash 5 flash6607No ACK signal - check A- M-Net wiring, range of transmission wiring exceeded
or if faulty A- M-Net converter
A82 flash 5 flash6608M-Net no response - check A- M-Net wiring, range of transmission wiring
exceeded, faulty A- M-Net converter or if incorrect wire used for M-Net connection
EA--6844Mis-wiring/loose inter-connecting cables. Noise interference.
EB--6845Mis-wiring/loose interconnecting cables. Noise interference. Wrong cable size/spec
EC--6846Start-up time over . The unit has failed to initialise after power up.
Noise interference. Wrong cable size/spec.
ED2 flash5 flash403Serial communication error . Comms error between boards on outdoor unit
caused by M-Net interface board incorrectly fitted.
EF2 flash4 flash6607Non-defined error code. Noise interference - power down outdoor unit for 30 seconds
then switch back on
E02 flash3 flash-Remote controller communication error - check wiring, connections and comms
voltage. Also check Master/Slave settings if multiple systems are connected
E1---Remote controller issue - if grouped, check addressing. If twinned, check
wired to master indoor only
E32 flash3 flash-Remote controller issue - not transmitting - if grouped, check addressing.
If twinned check wired to master indoor only
E42 flash3 flash-Remote controller issue - not receiving - if grouped, check addressing.
If twinned, check wired to master indoor only
E52 flash3 flash-
E62 flash2 flash6840Indoor/outdoor communication error , mainly caused by outdoor unit being powered
up before indoor unit. Drain pump being wired into S1 and S2 causes interference
E72 flash2 flash-Comms fault between I/C and O/C - check for condensate pump at I/C, reset
power to O/C, check 12/24Vdc on S2 and S3 possible I/C board failure
E8--6840Comms failure indoor to outdoor (S2/S3) - check pumps wired in, check indoor
isolator and re-power in the correct sequence i.e. indoor then outdoor
FA1 flash2 flash410851CM connector open - check thermal relay for disconnection or contact failure.
Possible defective board
F11 flash1 flash4103Reverse phase detection - check power supply, try swapping 2 phases round.
Possible defective board
F21 flash1 flash4102L3 phase open - check power supply, also check for open circuit protection devices
F31 flash2 flash520263L open - check low pressure switch for disconnection or contact failure.
Possible defective board
F41 flash2 flash412449C open - compressor inner thermostat for open circuit or contact failure
F51 flash2 flash520163H open - check high pressure switch for disconnection or contact failure.
Possible defective board
F71 flash3 flash4118Phase detection circuit fault - faulty outdoor board
F81 flash3 flashNo input detected at outdoor unit - outdoor board defective
F91 flash2 flash4119Two or more protection devices are open - check protection devices
for disconnection or contact failure
P14 flash1 flash-Return air thermistor fault (TH1) - check if TH1 disconnected or open or close circuit
P24 flash1 flash-Liquid pipe thermistor fault (TH2) check if TH2 disconnected or open or close circuit
P44 flash2 flash-Drain sensor fault - DS open or close circuit
P54 flash2 flash-High condensate level - drain pump failure or blockage in the drain
P64 flash3 flash-Freezing/Overheating of indoor unit heat exchanger - mainly caused by reduced
air flow through indoor coil. Dirty filters. Fan motor problem. Blockage.
P84 flash4 flash-Abnormal pipe temperature - mainly caused by refrigerant leakage.
Possibility that the thermistor mounted incorrectly
P94 flash1 flash-TH5 condenser/evaporator thermistor open/close circuit.
Disconnected from the board.
U13 flash2 flash1302High pressure trip - outdoor fan failure, blocked coil, blockage in the system,
blocked filters on indoor in heating etc
U23 flash1 flash1102High discharge temperature - compressor over heating due to lack of refrigerant,
faulty thermistor , high ambient running conditions. Can also be caused by 49C
(comp inner thermostat or external Klixon ) tripping
U33 flash5 flash5104Discharge thermistor fault
U43 flash5 flash5105Outdoor thermistor fault
U53 flash6 flash4230Inverter heat sink temperature too high (TH8) - check for lack of air flow around
heat sink, no silicone paste, faulty thermistor (temperature can be read from
service tool (or PAR21 on power inverter model))
U63 flash4 flash4250Compressor over current - carry out inverter output test and electrical checks
to the compressor
U73 flash1 flash1520Low discharge superheat - check TH4 reading is correct. Check LEV operations