Error code reference
LG Washer Error Code AC4
Communication error between the LCD Module and main PBA; signals not sensed due to incorrect or loose…
Communication error between the LCD Module and main PBA; signals not sensed due to incorrect or loose connector connections or faulty soldering.
First step from the service manual
1
Check the connector connections between the LCD Module and main PBA.
The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.
MyPros+ Max
Get the full diagnostic procedure for AC4.
- ✓Step-by-step tests with expected resistance, voltage, and continuity values
- ✓Wiring diagram references and connector pinouts from the OEM service manual
- ✓Verified part numbers when replacement is required
Get the full procedure→
$29/month · Cancel anytime · Or $9.95 3-day pass
M+
M+ Max·LG Washer
AC4 on my LG WM3900HWA
M+
Communication error between the LCD Module and
From Service Manual 604861, p.33:
1.Check the connector connections between the LCD Module and main PBA.
2.Inspect the communication harness between the main control and the UI board for bent pins or unseated connectors at each end.
3.Measure supply voltage to the UI board. Expected: 5 VDC at the interface connector; a low or missing rail points back to the main control supply.
Part EBR73304220
Display PCB assembly
Related LG washer codes
All LG washer codes →- 0tPCB temperature sensor short circuit error related to…
- 1Water inlet error
- 10Ball sensor error
- 11Suds Error
- 11CWater level sensor error (Upper washer)
- 11EWater leakage error (E9)
- 12Power failure
- 12ESwitch error (USA designation) equivalent to bE1; Power…
View all 349 LG washer codes
- 13CWashing motor error and hall sensor error (Upper washer)
- 13ESwitch error (USA designation) equivalent to bE2; a button…
- 14CWater supply error (Upper washer)
- 14C2Water supply error (Upper washer)
- 14ESwitch error (USA designation) equivalent to bE3; main…
- 15CDrain error (Upper washer)
- 18C1MEMS PB error (Upper washer)
- 18C2MEMS PB error (Upper washer).
- 19C1Power error (Upper washer)
- 19C2Power error (Upper washer)
- 1ACCommunication error (Upper washer)
- 1AC4Communication error (Upper washer)
- 1AC6Communication error (Upper washer)
- 1AC7Communication error (Upper washer)
- 1bC2Switch error (Upper washer)
- 1CWater level sensor error caused by damaged/clogged/folded…
- 1dCDoor error (Upper washer)
- 1dC1Door error (Upper washer)
- 1dC4Door error (Upper washer)
- 1EWater level sensor error
- 1HCHeater error (Upper washer)
- 1HC1Heater error (Upper washer)
- 1LCWater leakage error (Upper washer)
- 1LC1Overflow error (Upper washer)
- 1OCOverflow error (Upper washer)
- 1SSystem error (Upper washer)
- 1SUdFoaming detected (Upper washer)
- 1tC1Temperature sensor error (Upper washer)
- 1tC4Temperature sensor error (Upper washer)
- 1UBUnbalance error (Upper washer)
- 2Imbalance error
- 2044Work windings open
- 2046Capacitor open
- 2048Motor shorted
- 2145Timer does not advance
- 2148Timer open
- 2EPower error
- 3Drain error
- 3CMotor driving error and hall sensor error
- 3EMotor driving error
- 3E1Hall Sensor error
- 3E2Motor overloaded due to too much laundry (non-sensing)…
- 3E3PBA connector terminal not connected, motor spin net not…
- 3E4Motor error
- 4Overflow error
- 4CWater supply error
- 4C2Water supply check occurring if PCB terminal from drain…
- 4EWater supply error caused by foreign material in the water…
- 4E1Hot water supply error during drying
- 4E2Water supply error
- 4EdWater supply error during dry cycle where water temperature…
- 5Pressure sensor error
- 5CDrain error
- 5EDrain error caused by damaged pump motor impeller, wrong…
- 6Door open error
- 6CPower error due to consumer power conditions, under or over…
- 6EWater Heater Error
- 7Heating error
- 7EHall sensor error indicating the motor hall sensor is not…
- 8Locked Motor Error
- 888Water level error
- 8CMEMS PBA error detected or data error detected; may also…
- 8C1MEMS PBA check detected or data check detected due to wire…
- 8C2Main PBA wire connection error or PBA silver nano part…
- 8EClutch motor error where the clutch position is not…
- 8E1MEMS PBA error detected or data error; check wire…
- 8E2Rear MEMS sensor PBA error
- 9Locked motor error
- 9CPower error due to under or over voltage supply, use of…
- 9C1Power error
- 9C2Power error
- 9EOvervoltage or low-voltage error
- 9E1Power error
- 9E2Power supply undervoltage
- ACCommunication error
- AC2Communication check error where signals between the DR…
- AC3Communication error between the WIFI Module and main PBA…
- AC5Communication error between the Inverter PBA and main PBA…
- AC6Communication check between Inverter PBA and main PBA not…
- AC7Communication error
- AECommunication error
- AE3Communication error between the DR Module and main PBA…
- AE4Communication error between the WIFI Module and main PBA…
- AE5Communication error between the LCD Module and main PBA…
- AE6Communication error between the Inverter PBA and main PBA…
- AOAuto Off relay failure
- AUTO OFFAuto Off relay is out of order; indicated by BLUE(BL) 1-pin…
- Auto Off ErrorAuto Off relay is out of order; Blue (BL) 1-pin connector…
- BALL PRESSURE SENSORBall Pressure Sensor is disconnected or defective…
- Ball Pressure Sensor ErrorBall Pressure Sensor is disconnected; indicated by all…
- BCSwitch check
- bC2Switch error (Main Relay Error)
- bEMotor error caused by erroneous operating signals from the…
- bE1Switch error where the Power button is pressed continually…
- bE2Switch error (Main Relay Error) where Power button is…
- bE3Main relay error
- BPBall Pressure Sensor is disconnected or defective (all…
- BRBrake resistor error.
- bSBall sensor error
- C1Water level sensor fault
- C2Motor driving check
- C3Motor hall sensor check
- C4Water supply check
- C5Water supply check
- C6Drain check
- C7Mems PBA check
- C8Mems PBA main PBA wire connection check or PBA silver nano…
- C9MEMS PBA check
- CCPower check
- CdCoupling error.
- CELock error
- CH01Indoor temperature sensor open/short circuit fault.
- CLLid locked error
- COCoupling error during operation.
- CPCoupling error.
- CrClutching error.
- CVSupplied voltage is not correct
- d75Dryer
- d80Dryer
- d90Dryer
- d95Dryer
- DCDoor check
- DC1Door check error caused by incorrectly connected door lock…
- DC2Door check caused by door lock switch unit issues; occurs…
- DC3Door check during boil wash
- dC4Door error (Upper washer inner door open)
- dCLDoor open error
- DDCAdd door is opened; door error related to add door switch…
- dEDoor error (before operation)
- dE1Door error
- dE2Door error
- dE3Door/lid error
- dE4Dryer error where Main Micom detects door close while…
- dEzDoor open error
- dFWasher failed to lock the door.
- dHDry heating error
- dHEDryer heater error
- dLDoor error (during operation)
- dnPedestal washer is being operated without a full-size…
- DODoor open error
- doorDoor being not opened
- DOOR ErLid opened during washing procedure (wash, rinse, spin) or…
- DOOR LOCKDoor is not closed properly.
- DOOR OPENLid is opened during intermittent spin, normal spin, or…
- Door Open ErrorLid is opened during intermittent spin, normal spin, or…
- DRDrainage error
- DRAINThe water level does not go below RESET even 15 minutes…
- DRAIN ErDrain is not finished within 12 minutes during drain course.
- Drain errorWater level does not decrease to the reset point within 15…
- DRAINAGEWater is not completely drained within 10 minutes…
- Drainage ErrorWater is not completely drained within 10 minutes…
- drnDryer failed to drain water.
- dSDoor error (before operation) caused by a switch contact…
- dVDrain valve problem
- EWater supply error
- E-02Cooking time setting over error for microwave (MWO) mode.
- E-03Cooking time setting over error for grill mode.
- E-04Cooking time setting over error for convection mode.
- E-05Cooking time setting over error for combination mode.
- E-06Swing heater detection error
- E-0bCooling fan motor error
- E-11Gas sensor open error
- E-12Gas sensor short error.
- E-13Gas sensor T1 max time error
- E-14Gas sensor dry up / no load error
- E-21Temperature sensor open error
- E-22Temperature sensor short error.
- E-23Temperature sensor T1 max time error
- E-24Over temperature error
- E-25Abnormal temperature sensed at microwave cook mode
- E-26Temperature not rising above fixed AD value in first 3…
- E-27Temperature sensor open error variant.
- E-28Temperature sensor short error variant.
- E-29Temperature sensor open error variant.
- E-2ATemperature sensor short error variant.
- E-2BPCB temperature sensor open error
- E-2CPCB temperature sensor short circuit error
- E-31Weight sensor open error
- E-32Weight sensor short error.
- E-33Weight sensor error
- E-34Weight sensor error
- E-35Weight sensor error
- E-36Door opens during sensor cooking (weight sensor mode).
- E-41Easy/PH sensor open error.
- E-42Easy/PH sensor short error.
- E-43Easy/PH sensor T1 max time error.
- E-44Easy/PH sensor dry up error.
- E-45Easy/PH sensor cooling error
- E-46Easy/PH sensor primary open error (3 minutes).
- E-47Door opens during cooking (PH sensor mode).
- E-51EEPROM open error
- E-53EEPROM read/write error.
- E-54EEPROM zero not to be set error.
- E-61Humidity sensor open error.
- E-62Humidity sensor short error.
- E-63Humidity sensor T1 max time error.
- E1Water Supply Error
- E2Switch error (main relay error) caused by the Power button…
- E3Motor Driving Error and Hall Sensor Error
- E4Unbalance Error
- E5Water heater error
- E6Heater overheated error
- E7Pressure Switch Assembly Error
- E8Abnormal Water Temperature Error
- E9Water Leakage Error
- EAAbnormal Water Temperature Error
- EBMotor Triac Short Error
- EcThermistor Error
- EdAbnormal water temperature error
- Ed1Breakdown detergent pump
- Ed2Open circuit detergent pump
- Ed3Breakdown softener pump
- Ed4Open circuit softener pump
- Ed5Automatic detergent injection pump connector missing or…
- EEErroneous operating signals from motor hall sensor, IPM…
- EE1Switch error
- EE2Switch error
- EE3Main relay of PBA is short-circuited, main relay terminal…
- EEEEModel option Error detected during Quick Test Mode.
- EEPROMEEPROM error
- EgEEPROM I/O test passed; no error detected.
- EILocked motor error
- EPEEPROM error
- ErAmbient temperature sensor failure
- EtEEPROM I/O error detected during PCB test mode; displayed…
- F1Dry ignition detection
- F5Dryer drainage pump doesn't work well
- FEDry duct fan error
- FFNFC module error
- FLDoor lock fail
- gASGas supply or service turned off (gas dryer model only).
- GFUnbalance error
- H1Thermistor dry error
- H2Thermistor wash error
- H3Thermistor dry overheating error
- H4Thermistor wash overheating error
- H5Water temperature error
- H6Heater wash error
- H7Heater dry error
- H8Heater wash overheating error
- HCHeater check error caused by washing heater short-circuit…
- HC1Heater error
- HC2Water level sensor operates without water (freezing or…
- HEHeater overheat error
- HE1Heater error
- HE2Dry heater malfunction
- HE3Heater relay error
- HIAmbient temperature reading above 50°C; displayed when…
- HrHeater relay error
- HSPedestal washer is being operated without a full-size…
- IEWater supply error
- IFWithout filter
- IMBALANCELoad is out of balance; the appliance imbalance detection…
- INLET ErWater supply does not reach the set level within 60 minutes.
- ISIce Maker Sensor failure or Water Tank Sensor failure.
- LAUNDRY AMOUNT SENSORIn the second QC mode a laundry amount sensor error is…
- LCWater leakage error
- LC1Water leakage check
- LEWater leakage error
- LE1Water level sensor error caused by damaged, clogged, or…
- LE2Compressor is restricted
- LE3Fan motor detects lock (Fan Error Code 71).
- LODoor unlock fail
- MOTOR ERRORMotor error
- nCNFC module error
- ndDrain error caused by damaged pump motor impeller, wrong…
- nENozzle (Vario) error
- nFWater Supply Error
- nF1Water supply error in Wool course
- NO DRAINWater is not completely drained within 12 minutes
- NO INLEWater supply error
- NO INLETWater level does not rise to the set level within 30…
- nPNot enough voltage from outlet (lower than 240V)
- nSDoor error before operation (USA variant) indicating door…
- nUNFC version error
- OCOverflow error
- OEOverflow error where water is supplied continually because…
- OE (overflow)Overflow error
- OFOverflow error
- OPnDrawer open error
- OVER FLOODINGOverflooding error displayed during the second QC Mode…
- Over Flooding ErrorDetected during second QC Mode; all process LEDs blink…
- Overflow errorOverflow condition rises for three times.
- PCClutch motor error when position of the clutch cannot be…
- PC1Clutch sensor check
- PEClutch motor hall sensor error where after completion of…
- PE1Clutch motor hall sensor error where after clutch position…
- PFPower failure
- PFEPump filter error
- PH1Power error due to under or over voltage supply, or use of…
- PloPower error
- PoFPower failure compensation
- PRESSURE SENSORSignal continuously ringing
- PSDryer power supply wire connection is wrong or loose…
- rEOver load in motor.
- SSystem error
- SdSuds error
- SELocked motor error
- SFSystem error in case of EEPROM detected fault or PBA…
- SF1System error due to micro controller operation failure.
- SF2System check
- SF3System check
- SPIN ErUnbalanced water or load detected during spin procedure.
- SrSwitch error
- StackEPedestal washer is being operated without a full-size…
- StucForeign object such as coin, pin, or clip is stuck in the…
- SudFoaming detected
- SUDSFoaming detected
- svdOversudsing detection
- TCTemperature sensor check
- tC1Temperature sensor error (washing)
- TC2Temperature sensor check error caused by dry temperature…
- TC3Heater sensor fault
- tC4Temperature sensor error
- tcLTub Clean alarm
- tETemperature sensor error
- tE1Temperature sensor error
- tE2Temperature sensor error
- tE3Temperature sensor error where the duct condensing…
- tE4Steam generator thermistor open or shorted (displayed in…
- TE5Eva Out temperature is abnormal (detected below -30 degrees…
- tHTemperature sensor error
- tSTemperature sensor fault
- tS2Dryer compressor discharge pipe thermistor temperature…
- UBUnbalance error
- UcPower error
- UEUnbalance error
- UNBALANCELaundry unbalance detected during spin; indicated by Wash…
- Unbalance ErrorLaundry unbalance detected during spin; indicated by Wash…
- uSVibration sensor error
- UVUnbalance error caused by motor hall sensor fault or…
- VSVibration sensor error
- WATER ERRWater supply error
- WATER LEVEL SENSORThe water level frequency stays over 30.0KHz or below…
- Water level sensor errorWater level sensor fails to send signal for longer than 15…
- WATER SUPPLYWater is not supplied up to the selected level even 60…
- WATER SUPPLY & INLET V/VWater level does not rise to the set level within 40…
- Water supply errorNo frequency change for 60 minutes from water supply (water…
- water supplying ErrorThe water level does not reach the selected water level…
- WIFIWIFI Modem is not connected or WIFI Modem Self Check…
- WSWater supply/inlet valve error
78,000+ service manuals · 160,000+ error codes · 55+ brands
Get Started →$29/month · Cancel anytime · Or $9.95 3-day pass