Acson AC Error Codes And Messages (Full List)

Acson Malaysia was founded in 1984 and was at that time known as the O.Y.L manufacturing company Sdn. However, in 2006 the company was acquired by Daikin, a multinational air conditioning manufacturer, and supplier based in Japan. With headquarters in Osaka, the company offers its products in China, Japan, the United States, India, Australia, Southeast Asia, the Middle East, Europe, Africa, and even Latin America.

Error codes are a common issue you may face with various appliances in your house or workplace. Rather than panicking, we suggest you grab a pen and paper and note down the code rather than pressing various buttons. This can commonly result in prolonging the issue or even causing more issues in the long run. So why risk damaging your appliance any further, when you will be able to find out the exact issue using the common error code list for Acson AC error codes listed below. Once you know the exact issue you can easily call in a professional, or fix the issue yourself.

Wall Mounted AC Inverter Unit Codes

The code indication changes as shown below, and notifies with a long beep.

Error CodesSolutions
E1Room air sensor contact loose / short. Check room sensor connection / change room sensor
E2 Indoor coil sensor contact open. Check indoor coil sensor connection / change indoor coil sensor
E3Outdoor coil sensor contact open. Check outdoor coil sensor connection / change outdoor coil sensor
E4Compressor overload protection / Indoor / Outdoor coil sensor short. If running ampere highly increase, change the compressor. If not, replace the coil sensor
E5Gas leak. Check for leakage & repair / Top up refrigerant
E6 Pump fault. Clear the clogging at drain pipe. If pump is not working, change the pump
E7 Outdoor coil sensor exist (MS model). Remove outdoor coil sensor
E8Hardware error (tact switch pin short). Check for the tact switch pin condition
E9No Feedback from indoor fan. Check indoor fan motor / fan motor wiring
EE EEPROM defrost

Error Codes for G18 and GS02 – Inverter Y Models

Netware 3C / SLM 9 – Inverter Y Models (Except 5WMY-J/JR)

Error CodesProblem
U0Insufficient gas
U2DC voltage out of range
U4Communication error
U7 Signal transmission error (on outdoor unit PCB)
UAInstallation error
UFCommunication Error (indoor and outdoor) piping and wiring
UHAnti-freeze function in other room
A1 Indoor PCB error
A3Water pump error
A6Indoor fan motor abnormal
C4Indoor heat exchanger thermistor short/ open
C9Indoor room thermistor short/ open
E1Outdoor PCB error
E3 High pressure protection
E4 Low pressure protection
E5Compressor motor lock
E6Compressor start-up error
E7 Outdoor DC fan motor lock
E8Ac input over current
E9EXV error
EA4-way valve error
F3Discharge pipe overheat
F6Heat exchanger overheat
H0Compressor sensor system abnormality
H3 High pressure switch error
H6 Position sensor abnormality
H8 AC current sensor error
H9Outdoor air thermistor short / open
J1 Pressure sensor error
J3 Compressor discharge pipe thermistor short /open / misplaced
J5 Suction pipe thermistor short/ open
J6Outdoor heat exchanger
J7Subcooling heat exchanger thermistor short/ open
J8Liquid pipe thermistor short/ open
J9 Gas pipe thermistor abnormality
LCCommunication error (control PCB and inverter PCB)
L1Outdoor PCB error
L3Electrical box temperature rise
L4Heat sink overheat
L5 IPM error / IGBT error
L9Stall prevention
P1Open phase or voltage unbalance
P4 Heat sink thermistor short / open
PJ Capacity setting error
Netware 3C - SLM 9 – Inverter Y Models
Netware 3C – SLM 9 – Inverter Y Models

Sequential Controller (SQ LCD) – SB & RT Multi Compressors

Error CodesProblems
E01Require manual reset (possible causes)
E02Compressor 1 high temperature (overload)
E03Compressor 2 high temperature (overload)
E04Compressor 3 high temperature (overload)
E05 Compressor 4 high temperature (overload)
E06Compressor 1 high pressure trip / contact open
E07Compressor 2 high pressure trip / contact open
E08Compressor 3 high pressure trip / contact open
E09 Compressor 4 high pressure trip / contact open
E10Compressor 1 trip/low refrigerant/outdoor abnormal
E11Compressor 2 trip/low refrigerant/outdoor abnormal
E12Compressor 3 trip/low refrigerant/outdoor abnormal
E13Compressor 4 trip/low refrigerant/outdoor abnormal
E14Room sensor short
E15 Room sensor open
E16Indoor coil sensor 1 short
E17Indoor coil sensor 2 short
E18 Indoor coil sensor 3 short
E19Indoor coil sensor 4 short
E20 Indoor coil sensor 1 open
E21Indoor coil sensor 2 open
E22 Indoor coil sensor 3 open
E23Indoor coil sensor 4 open
E24Outdoor coil sensor 1 short
E25Outdoor coil sensor 2 short
E26 Outdoor coil sensor 3 short
E27Outdoor coil sensor 4 short
E28 Outdoor coil sensor 1 open
E29Outdoor coil sensor 2 open
E30 Outdoor coil sensor 3 open
E31Outdoor coil sensor 4 open
E32Compressor 1 de-ice
E33 Compressor 2 de-ice
E34 Compressor 3 de-ice
E35Compressor 4 de-ice

Error Diagnosis by Wired Controller (MC301)

Error Diagnosis by Wired Controller (MC301)
Error Diagnosis by Wired Controller (MC301)
Error CodesMeaning
F3Sensor Broken (indoor outlet coil)
F4Sensor Broken (indoor return air)
F5 Sensor Broken (indoor supply air)
F6Indoor and controller communication malfunction
F7Ambient temp exceed the limit
F8 4WV malfunction
F9Refrigerant leakage
FAController storage malfunction
FBWater Pump (indoor water pump)
FCIndoor and outdoor communication malfunction
FEMaster and slave communication malfunction
H0Digital comp overload
H1Fixed Comp1 overload
H2Fixed Comp2 overload
H3Fixed Comp3 overload
H4 High pressure too high
H5 Sensor broken, high pressure
H6 Discharge temp too high
L0 Super heat too low
L1Low pressure too low
L2Sensor broken, low pressure
10System malfunction
11 Sensor broken (slave TH1 discharge temp)
12Sensor broken (slave TH2 inlet coil 1#)
13Sensor Broken (slave TH3 mid coil 1#)
14Sensor broken (slave TH4 inlet coil 2#)
15Sensor broken (slave TH5 mid coil 2#)
16 Sensor broken (slave TH6 inlet coil 3#)
17Sensor broken (slave TH7 mid coil 3#)
18 Sensor broken (slave TH8 ambient temp)
19 Sensor broken (slave TH9 outlet coil)
1ASensor broken (slave TH10 subcool outlet)
1BSensor broken (slave TH11 subcool suction)
1C Sensor Broken (slave TH12 suction)
1F Emergency run (slave)
20 Outdoor storage (slave)
27Ambient temp exceed the limit (slave)
284WV malfunction (slave)
29Refrigerant leakage (slave)
30 Digital comp overload (slave)
31 Fixed comp1 overload (slave)
32Fixed comp2 overload (slave)
33Fixed comp 3 overload (slave)
34High pressure too high (slave)
35Sensor broken, high pressure (slave)
36Discharge temp too high (slave)
40Super heat too low (slave)
41 Low pressure too low (slave)
42 Sensor broken, low pressure (slave)

R410A Multi Digital Scroll System MDS-B Series

R410A Multi Digital Scroll System MDS-B Series
R410A Multi Digital Scroll System MDS-B Series
Error CodesMeaning
EC0000## indoor unit communication
EC01 01# indoor unit communication failure
ER48Digital Compressor Overload
ER49 Fix 1 Compressor Overload
ER50Fix 2 Compressor Overload
ER51 Fix 3 Compressor Overload
ER52 Discharge pressure too high
ER53Suction pressure is too low
ER54Outdoor unit’s IC error
ER55System Error
ER56 Discharge temperature is too high
ER584 way valve failure
ER59Ambient temperature is beyond the limit
ER60Emergency run
ER61Sub heating is beyond the limit
ER62Refrigerant released
ER63Slaver outdoor unit communication failure
ER64TH1 temperature sensor failure
ER65TH2 temperature sensor failure
ER66 TH3 temperature sensor failure
ER67TH4 temperature sensor failure
ER68TH5 temperature sensor failure
ER69TH6 temperature sensor failure
ER70 TH7 temperature sensor failure
ER71 TH8 temperature sensor failure
ER72TH9 temperature sensor failure
ER73 TH10 temperature sensor failure
ER74 TH11 temperature sensor failure
ER75TH12 temperature sensor failure
ER76Discharge pressure sensor failure
ER77Suction pressure sensor failure
EC78All indoor units Communication Failure

LED Lights Diagnosis Table

Acson LED Lights Diagnosis Table
Acson LED Lights Diagnosis Table


If any malfunction of the air conditioner unit is noted, immediately switch off the power supply to the unit. Check the following fault conditions and causes for some simple troubleshooting tips.

Fault: The compressor does not operate 3 minutes after the air conditioner unit is started.

Causes / Action: -Protection against frequent starting. Wait for 3 to 4 minutes for the compressor to start operating.

Fault: The air conditioner unit does not operate.

Causes / Action:

– Power failure, or the fuse needs to be replaced.
– The power plug is disconnected.
– It is possible that your delay timer has been set incorrectly.
– If the fault persist after all these verifications, please contact the air conditioner unit installer.

Fault: The air flow is too low

Causes / Action:

– The air filter is dirty.
– The doors or windows are open.
– The air suction and discharge are clogged.
– The regulated temperature is not high enough

Fault: Discharge air flow has bad odour.

Causes / Action:

– Odours may be caused by cigarettes, smoke particles, perfume etc. which might have adhered onto the coil.

Fault: Condensation on the front air grille of the indoor unit.

Causes / Action:

– This is caused by air humidity after an extended long period of operation.
– The set temperature is too low, increase the temperature setting and operate the unit at high fan speed.

Fault: Water flowing out from the air conditioner unit.

Causes / Action: – Switch off unit and call dealer

Fault: Hissing air flow sound from the air conditioner unit during operation.

Causes / Action: – Refrigerant fluid flowing into the evaporator coil

If the fault persists, please call your local dealer / serviceman

Wiring Diagram

Acson Air Conditioner Wiring Diagram
Acson Air Conditioner Wiring Diagram


Acson Wall Mounted Split Systems AWM Manual PDF

Acson Ceiling Cassette Split Type Air Conditioner Manual PDF

Acson ART55A Rooftop Packaged Air Conditioners Technical Manual PDF

Danny Reese

*If you can't find the code you're looking for on our site, please let us know, and we'll update our database as soon as possible.

30 thoughts on “Acson AC Error Codes And Messages (Full List)”

  1. Hi there. I dont have acson model number. But i bought it back in 2011 and till date its working ausome. I have single issue that it does not tripped and i manually shut down split unit due to extremely cold. It doesnt auto tripped even on 30 c even..plz help me out


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