Model reference

LG FM57AH

Air Conditioner

1 document37 error codes6 service modes

Available documentation

Service Manual

Air Conditioner Service Manual - Multi-Inverter Type137 pg
Covers this model

MyPros+ Max

Diagnose your LG FM57AH.

Step-by-step diagnostics from the service manual
Test values, resistance specs, and wiring references
Verified part numbers when replacement is needed

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M+

M+ Max·LG Air Conditioner

01 on my LG FM57AH

M+

Indoor air sensor open/short circuit

From Service Manual 253595, p.47:

1.Access service mode to confirm the active fault code and read stored error history.

2.Measure door lock assembly resistance across PTC terminals. Expected: ~200 ohms cold.

3.Inspect strike and latch alignment. A misaligned strike prevents the switch stack from closing.

Part 6601ER1004C

Door lock assembly

Error codes (37)

CodeMeaning

01Indoor air sensor open/short circuit error.02Indoor inlet pipe sensor open/short circuit error.03Communication error between indoor unit and wired remote controller.04Drain pump / float switch error (float switch open).05Communication error between indoor and outdoor units (displayed on indoor unit).06Indoor outlet pipe sensor open/short circuit error.07Different operation mode error 09Indoor EEPROM check sum error.10Indoor BLDC fan motor lock 21DC Peak / IPM Fault 22CT2 / Max CT 23DC link low voltage 24Low pressure / high pressure switch open.25Abnormal AC input voltage (below 140Vac or above 300Vac).26DC compressor position detect error 27PSC/PFC fault error 28DC link high voltage 29Inverter compressor over current 32Inverter compressor discharge pipe temperature high (over 105°C).33Constant compressor discharge pipe temperature high (over 105°C).39Communication error between PFC micom and INV micom on inverter PCB.40CT sensor circuit malfunction (open/short).41Inverter discharge pipe thermistor error (open/short).44Outdoor air thermistor error (open/short).45Condenser pipe thermistor error (open/short).46Suction pipe thermistor error (open/short).47Constant compressor discharge pipe thermistor error (open/short).51Over capacity combination 52Signal/transmission error between inverter PCB and main PCB.53Communication error between indoor and outdoor units (displayed on outdoor…

View all 37 error codes

543-phase wrong wiring of outdoor unit (reverse phase or phase omission).60EEPROM check sum error on outdoor unit (inverter PCB and/or main PCB).61Condenser pipe thermistor detected high temperature (65°C).62Heat sink thermistor detected high temperature (85°C).65Heat sink thermistor error (open/short).67Outdoor BLDC fan lock 73PFC fault error (software)

Service modes (6)

Child LockPress the preset and minute setup buttons simultaneously for 3 seconds
E.S.P. (External Static Pressure) Setting1
Forced OperationPress the ON/OFF button on the indoor unit display panel. The operating condition is set…
Test Run (Cassette type)Press the button on the indoor unit for 5 seconds to start test run
Test Run (Ceiling Cassette type)Press the room temperature checking button and down timer button simultaneously for 3 seconds.
Test Run (Room/Wall type)Press the timer cancel button five times continuously on the indoor unit.

Full entry steps, exit procedures, and test sequences are available in Max.

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