Here on the page there are lists of error codes for different models of Mitsubishi air conditioners. Mitsubishi fault codes are described separately for each model and accompanied with detailed description of technique behavior and possible causes.
In case if the item has error codes and flashes, the tables contain both of the signals. Several causes are given for every error code. The lists contain also the solutions and recommendations on checking the items. You can solve the situation by changing or repairing a remote control or by checking the wires. If there is any serious repair needed, ask for a specialist’s help.
Mitsubishi Mr. Slim Air Conditioner Fault Codes
Check code | Diagnosis of malfunction | Cause | Check points |
---|---|---|---|
EO | Signal transmitting/receiving error | During individual unit control | 1) Check the transmission wire. |
(Indoor controller does not respond to remote controller signal.) | 1) Bad contact of transmission wire | 2) Check with another remote controller. If ■‘EO" is still indicated, replace the indoor controller board. | |
2) Signal transmitting/receiving circuit is abnormal. | If other check code appears, replace the original remote controller. | ||
P1 | Abnormality of room temperature thermistor (RT1) | 1) Bad contact of thermistor | 1) Check the thermistor. |
2) Damaged thermistor | 2) Measure the resistance of the thermistor. Normal resistance should be as follows. 32T-15K2 86°F 4.3ki2 | ||
50° F 9.6k£2l04°F 3.0k£2 | |||
68°F 6 3ki2 | |||
P2 | Abnormality of indoor coil thermistor (RT2) | If the resistance is normal, replace the indoor controller board. | |
P3 | Signal transmission error (Remote controller does not respond to indoor controller signal.) | 1) Bad contact of transmission wire | 1) Check the transmission wire. |
2) Signal transmitting/receiving circuit is abnormal. | 2) Check with another remote controller. | ||
3) Wrong operation due to noise wave emitted by other appliances | If “P3’ is still indicated, replace the indoor board. | ||
If other check code appears, replace the original remote controller. | |||
3) Short-circuit between D and (2) of CN40 and attach CN40 to the following units. | |||
• Second unit in twin control | |||
• Second and third units in triple control | |||
• Sub units in group control | |||
P4 | Abnormality of drain sensor | 1) Bad contact of transmission wire | 1) Check the connector. |
2) Damaged thermistor | 2) Measure the resistance of the thermistor As for the normal resistance, refer to the case of P1. | ||
If the resistance is normal, replace the indoor controller board. | |||
P5 | Malfunction of drain pump | 1) Malfunction of drain pump | 1) Check the drain pump. |
2) Damaged drain sensor | 2) • Check the drain sensor. | ||
• Check the drain sensor heater. Normal resistance should be 8212. | |||
If the resistance is normal, replace the indoor controller board. | |||
P6 | Coil frost protection is working. | 1) Short cycle of air cycle | 1) Clear obstructions from the air cycle. |
2) Dirty air filter | 2) Clean the air filter | ||
3) Damaged fan | 3) Check the fan. | ||
4) Abnormal refngerant | 4) Check the refrigerant temperature. | ||
P7 | System error | 1) Wrong address-setting | 1) Check the address-setting. |
2) Signal transmitting/receiving circuit of remote controller is abnormal. | 2) Check with another remote controller. If check code other than “P7” appears, replace the original remote controller. | ||
3) Wrong SW6-setting | 3) Check SW6 setting. | ||
P8 | Abnormality in outdoor unit | 1) Wrong wiring of indoor/outdoor connecting wire | 1) Check the indoor/outdoor connecting wire. |
2) Reversed phase | 2) Change the connection of electric wiring. | ||
3) Protection device is working | 3) Check the protection device. | ||
4) Damaged outdoor coil thermistor | 4) Measure the resistance of the outdoor coil thermistor. If the resistance is normal, replace the outdoor controller board. |
Mitsubishi Mr Slim P Series Air Conditioner Fault Codes
Indoor unit indicator RUN light | Indoor unit indicator TIMER light | Outdoor unit Indicator LED | Wired remote Controller display (optional part) | Description of trouble | |
---|---|---|---|---|---|
Come s ON | 1 time flash | 1 time flash | E42 | Current cut | • Compressor locking |
• Open phase on compressor output | |||||
• Short circuit on power transistor | |||||
Come s ON | 2 time flash | 2 time flash | E59 | Trouble of outdoor unit | • Defective power transistor |
• Broken compressor wire | |||||
• Compressor blockage | |||||
Come s ON | 3 time flash | 3 time flash | E58 | Current safe stop | • Overload operation |
• Overcharged | |||||
Come s ON | 4 time flash | 4 time flash | E41 | Power transistor error | • Broken power transistor |
Come s ON | 5 time flash | 5 time flash | E36 | Over heat of compressor | • Gas shortage |
• Defective discharge pipe sensor | |||||
Come s ON | 6 time flash | 6 time flash | E5 | Error of signal transmission | • Defective power supply |
• Broken signal wire | |||||
• Defective indoor/outdoor PCB | |||||
Come s ON | 7 time flash | Comes ON | E48 | Outdoor fan motor error | • Defective fan motor |
• Poor connector connection | |||||
2 time flash | 2 time flash | 7 time flash | El | Error of wired remote controller wiring | • Broken remote control wire |
• Defective indoor unit PCB |
Mitsubishi PWFY Air Conditioner Fault Codes
FAULT CODE | I DESCRIPTION |
---|---|
E1 | Faulty controller |
E3 | Transmitting Error (PAR W21) - check refrigerant address on SW1 of Ecodan |
E4 | Receiving Error (PAR W21) - check refrigerant address of SW1 on Ecodan |
E5 | Receiving Error (PAR W21) - check refrigerant address of SW1 on Ecodan |
E6 | Indoor/Outdoor communication error - mainly due to Ecodan being powered up before FTC(2) |
E8 | Indoor/Outdoor communication error - mainly due to Ecodan being powered up before FTC(2) |
E9 | Indoor/Outdoor communication error - mainly due to Ecodan being powered up before FTC(2) |
EF | Non-defined error code - noise interference - power down Ecodan for 30 seconds then switch back on |
ED | Serial communication fault between Ecodan main board and Ecodan inverter board - mainly due to loose CN2 or CN5 cable |
P1 | Flow temp sensor fault - TH1 not connected, short or open circuit |
P6 | Over heating at heat exchanger - lack of water flow, air in the system, flow rate incorrectly set, blockage or pump problem |
Mitsubishi CAHV Air Conditioner Fault Codes
Code | Symptom |
---|---|
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.) |
EO, 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 super heat 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 Ecodan Air Conditioner Fault Codes
Indoor unit indicator RUN light | Indoor unit indicator TIMER light | Outdoor unit Indicator LED | Wired remote Controller display (optional part) | Description of Trouble | |
---|---|---|---|---|---|
1 time flash | Comes ON | Stays OFF | E6 | Indoor heat exchanger sensor 1 error | • Broken heat exchanger sensor 1 wire, |
• Poor connector connection | |||||
2 time flash | Comes ON | Stays OFF | E 7 | Room temperature sensor error | • Broken room temperature sensor wire, |
• Poor connector connection | |||||
4 time flash | Comes ON | Stays OFF | E9 | Drain abnormal (STM. SRRM only) | • Float switch defective, |
• Reverse gradient on drain | |||||
5 time flash | Comes ON | Stays OFF | E6 | Indoor heat exchanger Sensor 2 error | • Broken heat exchanger sensor 2 wire, |
• Poor connector connection | |||||
6 time flash | Comes ON | Stays OFF | El 6 | Indoor fan motor error | • Defective fan motor, |
• poor connector connection | |||||
7 time flash | Comes ON | Stays OFF | E6 | Refrigerant insufficient Closed service valve Heat exchanger sensor 1 error | • Refrigerant is insufficient, leaking |
• Closed service valve | |||||
• Heat exchanger sensor 1 wire, | |||||
• poor connector connection | |||||
Keeps | 1 time flash | Keeps flashing | E38 | Outdoor air temperature sensor error | • Broken outdoor sensor wire, |
flashing | • poor connector connection | ||||
Keeps | 2 time flash | Keeps flashing | E37 | Outdoor heat exchanger sensor error | • Broken heat exchanger fluid pipe sensor wire, |
flashing | • poor connector connection | ||||
Keeps | 4 time flash | ON 4 sec OFF 4 sec | E39 | Discharge pipe sensor error | • Broken discharge pipe sensor wire, |
flashing | • poor connector connection | ||||
Keeps | 5 time flash | Keeps flashing | E53 | Suction pipe sensor error | • Broken suction pipe sensor wire, |
flashing | • poor connector connection | ||||
Keeps | 6 time flash | Keeps flashing | E41 | Power transistor sensor error | • Broken power transistor sensor wire, |
flashing | • poor connector connection |
Mitsubishi City Multi Air Conditioner Fault Codes
FAULT CODE | DESCRIPTION |
---|---|
F3 | Low pressure switch failure - check connection on the board and continuity of switch |
F5 | High pressure switch failure - check connection onto board and continuity of switch |
F9 | Both pressure switch contacts are open at the same time - check connection onto board and continuity of switch and for a potential board failure |
EA | Mis-wiring fault between FTC and Ecodan - check S1 ,S2,S3 also check voltages and comms |
EB | Mis-wiring fault between FTC and Ecodan - Check S1 ,S2,S3 also check voltages and comms |
EC | Unit cannot finish start up process - generally caused by a comms fault |
U1 | Ecodan high pressure fault - mainly caused by incorrect water flow rates - check with flow setter |
U2 | Ecodan high compressor discharge temperature - mainly caused by refrigerant shortage or dirty condenser |
U3 | Ecodan discharge thermistor problem - mainly caused by TH4 discharge thermistor - open/close circuit |
U4 | Open or close circuit Ecodan thermistors (TH3, TH32, TH33, TH6, TH7, TH8) - open or close circuit or disconnected from main board |
Mitsubishi Mr.Slim A Air Conditioner Fault Codes
FAULT CODE | LED 1 | LED 2 | I DESCRIPTION |
---|---|---|---|
AO | 2 flash | 5 flash | Duplicate address - Lossnay units attached with the same address - |
change addresses and reset the units power | |||
A2 | 2 flash | 5 flash | Hardware error of transmission processor (Lossnay) - check comms wiring, |
and for possible Lossnay board fault | |||
A3 | 2 flash | 5 flash | Line busy no data could be transmitted for 8 minutes - check A- M-Net |
connections (TB7 and TB3) | |||
A6 | 2 flash | 5 flash | Communication error with communication processor - Lossnay address not |
transmitted - check M-Net voltage | |||
A7 | 2 flash | 5 flash | No ACK signal - check A- M-Net wiring, range of transmission wiring exceeded |
or if faulty A- M-Net converter | |||
A8 | 2 flash | 5 flash | M-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 | - | - | Mis-wiring/loose inter-connecting cables. Noise interference. |
EB | - | - | Mis-wiring/loose interconnecting cables. Noise interference. Wrong cable size/spec |
EC | Start-up time over. The unit has failed to initialise after power up. | ||
Noise interference. Wrong cable size/spec. | |||
ED | 2 flash | 5 flash | Serial communication error. Comms error between boards on outdoor unit |
caused by M-Net interface board incorrectly fitted. | |||
EF | 2 flash | 4 flash | Non-defined error code. Noise interference - power down outdoor unit for 30 seconds |
then switch back on | |||
EO | 2 flash | 3 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 | |||
E2 | - | - | Remote controller issue - if grouped, check addressing. If twinned, check |
wired to master indoor only | |||
E3 | 2 flash | 3 flash | Remote controller issue - not transmitting - if grouped, check addressing. |
If twinned check wired to master indoor only | |||
E4 | 2 flash | 3 flash | Remote controller issue - not receiving - if grouped, check addressing. |
If twinned, check wired to master indoor only | |||
E5 | 2 flash | 3 flash | Remote controller issue - not receiving - if grouped, check addressing. |
If twinned, check wired to master indoor only |
Mitsubishi MR. SLIM MSY-A24NA Air Conditioner Fault Codes
Flashing | RUN light | Description of trouble | Cause |
---|---|---|---|
TIMER light ON | 1 Time flash | Heat exchanger sensor 1 error | • Broken heat exchanger sensor 1 wire, poor connector connection |
2 Time flash | Room temperature sensor error | • Broken room temperature sensor wire, poor connector connection | |
3 Time flash | Heat exchanger sensor 3 error | • Broken heat exchanger sensor 3 wire, poor connector connection | |
5 Time flash | Active filter voltage error | • Defective power supply | |
6 Time flash | Indoor fan motor error | • Defective fan motor, poor connector connection | |
7 Time flash | Refrigerant insufficient | • Refrigerant is insufficient, leaking | |
Closed service valve | • Closed service valve | ||
Heat exchanger sensor 1 error | • Heat exchanger sensor 1 wire, poor connector connection | ||
RUN light Keeps flashing | 1 Time flash | Outdoor temperature sensor error | Broken outdoor sensor wire, poor connector connection |
2 Time flash | Outdoor heat exchanger fluid pipe Sensor error | Broken heat exchanger fluid pipe sensor wire, poor connector connection | |
3 Time flash | Discharge pipe sensor error | Broken discharge pipe sensor wire, poor connector connection | |
5 Time flash | Suction pipe sensor error | Broken suction pipe sensor wire, poor connector connection |