How to diagnose an LG refrigerator: from error codes to checking the compressor

Refrigerators LG are famous for their reliability, but even they are not immune to breakdowns. If your unit begins to make noise, does not cool well, or displays errors on the display, do not rush to call a service technician. In 80% of cases, the problem can be identified on your own - just know how to correctly diagnose a refrigerator and what to pay attention to.

This article will help you understand the intricacies of diagnosing models LG with a system Smart Diagnosis, inverter compressors and electronic controls. We will look in detail at:

• 🔍 How to decipher error codes on the display and what they mean
• 🔧 Step-by-step check of the compressor, fan and thermostat
• ⚡ Testing methods electronics without special devices
• ❄️ Diagnostics of the No Frost system and signs of freon leak

We will pay special attention LG's unique self-diagnosis function - the Smart Diagnosis mode, which is available even without connecting to Wi-Fi. You will learn how to activate this mode and what data it provides to accurately determine the malfunction.

Important: if your refrigerator is still under warranty, some types of diagnostics (for example, disassembling the case) may lead to its loss. In such cases, it is better to contact the service center LG.

1. Primary diagnostics: what to check before disassembly

Before picking up tools, perform basic checks. They will help eliminate simple problems not related to equipment breakdowns.

Start with an inspection:

• 🔌 Make sure that the refrigerator is connected to the outlet. Check the voltage with a multimeter - it should be within 220±10 V.
• 🚪 Does the door close tightly? Carry out a test with a paper sheet: if it falls out, the seal requires replacement.
• 🌡️ Look at the temperature in the room. If the room is hotter +32°C, the refrigerator may not be able to cope with the load.

Then check the settings:

• 📱 On models with a display (LG Instaview Door-in-Door, LG ThinQ), reset the settings to factory settings through the menu Settings → Factory Reset.
• ❄️ refrigerators with No Frost make sure that the "Vacation" mode (Vacation Mode) is not activated, in which the freezer is on and the refrigerator is turned off.

Ring the socket with a tester|

Clean the rear grille from dust|

Check the door seal|

Make sure there is no overload of products|

Reset settings (if there is a display)-->

If after these steps the problem remains, proceed to in-depth diagnostics. Please note: some models LG (for example, series GR and GC) have a self-diagnosis function through the application LG ThinQ. Connect the refrigerator to Wi-Fi and check the error log in the mobile application.

⚠️ Attention: If the refrigerator makes noise strong chemical smell, immediately disconnect it from the network! This may indicate a leak of freon, a substance hazardous to health. In this case, professional repair is required.

2. Decoding error codes on the LG display

Modern refrigerators LG display faults in the form of alphanumeric codes. Decoding them will help narrow down the search for the problem.

On models without a display (for example, LG GA-B489), errors are displayed by blinking indicators. Explanation:

• 🔴 Red freezer indicator flashes 3 times: problem with the temperature sensor.
• 🟢 Green refrigerator indicator flashes 5 times: compressor or start relay malfunction.

How to reset the error on LG after eliminating the cause?

1. Unplug the refrigerator for 1 minute.

2. Turn it back on and immediately press the buttons Freezer and Fridge (or Express Freeze and Express Cool for some models).

3. Hold for 5-7 seconds until the display blinks or a beep sounds.

4. The error should clear. If not, the problem is not resolved.

If the error code does not match the table, use Smart Diagnosis mode. To do this:

1. Press and hold the button Express Freeze (or Ice Plus) for 8 seconds.
2. The refrigerator will emit a beep and start transmitting data.
3. Move the phone microphone to the front panel of the refrigerator (distance 3-5 cm).
4. Launch the application LG Smart Diagnosis and record the sound for 3-5 seconds.
5. The application will decipher the code and give recommendations.

⚠️ Attention: The Smart Diagnosis function only works on models LG released after 2018. For old refrigerators (for example, series LR 2015–2017), this method is not suitable.

3. Diagnostics of the No Frost system: why the refrigerator does not freeze

If your LG equipped with a system No Frost (this is most models, except for some budget series), but ice appeared in the freezer or the temperature rose higher -12°C, the problem lies in the system defrost.

Signs of a No Frost malfunction:

• ❄️ Ice (“fur coat”) is growing on the back wall of the freezer.
• 🌬️ The fan is louder than usual or stops periodically.
• 🔥 The refrigerator often turns on, but does not cool well.

For diagnostics:

1. Check the defrost heating element:
   • Turn off the refrigerator and defrost it.
   • Remove the back panel of the freezer cameras (unscrew the screws or remove the latches).
   • Find the heating element - this is a tube with wires located under the evaporator.
   • Test the heating element with a multimeter: there should be resistance 20–40 Ohm. If the device shows a break (OL) - the heating element has burned out.
2. Test the defrost sensor (defroster):
   • The sensor looks like a small plastic part with two wires.
   • At room temperature, its resistance should be 4–6 kOhm.
   • Place the sensor in ice for 10 minutes - the resistance should increase to 20–30 kOhm.

Check the timer defrost:

• On models with electromechanical control, the timer is located on the board or behind the front panel.
• Turn the timer knob clockwise until it clicks - the defrosting heating element should turn on.
• If the heating element does not heat up, the timer is faulty.

On models with Smart ThinQ (for example LG InstaView), the No Frost system is diagnosed automatically. If a notification appears in the application "Defrost System Error", this indicates:

• 🔌 Open circuit of the heating element or sensor.
• 🕒 Timer malfunction (for models without electronic control).
• ❄️ Fan freezing due to incorrect air circulation.

4. Checking the compressor: how to determine its performance

The compressor is the “heart” of the refrigerator. If it doesn't work, there will be no cooling. The models LG use two types of compressors:

• 🔄 Inverter (silent, with smooth power control). Installed in series GA, GC, GR.
• ⚡ Linear (traditional, with a starting relay). Found in budget models (LG LRF).

How to check the compressor without disassembling:

1. Unplug the refrigerator.
2. Remove the back cover (on some models it is enough to remove the bottom panel).
3. Find the compressor - it is a black cylinder with tubes and a relay.
4. Turn on the refrigerator and listen:
   • ✅ Inverter compressor It should work almost silently, with a slight hum.
   • ✅ Linear compressor makes a uniform buzz without clicks.
   • ❌ Clicks every 5-10 seconds indicates a faulty start relay.
   • ❌ Loud knocking or vibration is a sign of wear piston group.

Check with a multimeter:

1. Disconnect the refrigerator and discharge the capacitor (short-circuit it with a screwdriver with an insulated handle).
2. Disconnect the terminals compressor.
3. Ring the windings:
   • The resistance between C (common) and S (start) should be 2–5 Ohm.
   • Resistance between C and R (run) — 1–3 Ohm.
   • Between S and R there should be a total resistance (3–8 Ohm).

If at least one value is outside the limits, the compressor is faulty.

On models. s Smart Diagnosis the compressor is tested automatically. If an error "Compressor Error" or "ER CM"appears in the application, this may mean:

• 🔌 Broken windings or interturn short circuit.
• 🔋 Malfunction of the inverter board (for inverter models).
• 🛠️ Wear of the piston group (typical for compressors older than 10 years).

If the compressor does not turn on at all, check:

• 🔌 Start relay — it should click when turned on. If not, check. replace.
• 🔋 Control board —there should be no blackened elements or swollen capacitors on it.
• 📡 Thermostat —when its contacts are closed, the compressor should start.

⚠️ Attention: If the compressor is hot to the touch and turns off after 1-2 minutes of operation, this is a sign interturn short circuit. Further operation is dangerous - risk of fire!

5. Electronics diagnostics: control board and sensors

Modern refrigerators LG are controlled by electronic boards, which can also fail:

• 📵 The refrigerator does not respond to buttons or the display does not turn on.
• 🔄 Spontaneous reboots occur.
• 🔥 Blackened tracks or swollen capacitors are visible on the board.

How to check the board controls:

1. Disconnect the refrigerator from the network.
2. Remove the top cover (on most models the board is located there).
3. Inspect the board for:
   • 🔥 Blackened or burnt elements.
   • 💥 Swollen capacitors (they must be flat).
   • 🕸️ Oxidized or unsoldered contacts.

Ring the fuse (usually marked as F1 or F2) - the resistance should be 0 Ohm.

Checking temperature sensors:

In refrigerators LG 2-4 sensors are used (depending on the model):

• 🌡️ Refrigeration chamber sensor (usually located on the back wall).
• ❄️ Freezer chamber sensor (under the evaporator).
• 🌐 Ambient sensor environment (on the board or next to the compressor).

For testing:

1. Disconnect the sensor from the board.
2. Measure its resistance at room temperature (~25°C):
• ✅ Norm: 4–6 kOhm (for most models LG).
• ❌ Open circuit (OL) or short circuit (0 Ohm) - the sensor is faulty.

Place the sensor in a glass of cold water - the resistance should increase to 20–30 kOhm.

If the control board is faulty, you can:

• 🔧 Repair (replace burnt elements if you have soldering skills).
• 🆕 Replace with a new one (original boards for LG cost from 3,000 to 8,000 rubles).
• 💻 Reflash (relevant for models with Smart ThinQ, if the failure is caused by a software error).

On some models (for example, LG GR-B207) the control board is combined with the display. If the display does not turn on, but the refrigerator is working, the problem may be in the backlight or cable, and not in the board itself.

6. Diagnosis of a freon leak and a clogged capillary tube

If the compressor is working, but the refrigerator does not cool, two problems are possible:

1. Freon leak (refrigerant leaked through microcracks in the system).
2. Clogged capillary tube (oil or moisture plug).

Signs of a freon leak:

• 🔊 The compressor runs non-stop, but the freezer does not cool.
• 🌡️ The condenser (grid on the back wall) remains cold.
• 💨 At the leak site it may there may be an oil stain (freon comes out along with the oil).

Signs of a clogged capillary tube:

• 🔄 The compressor turns on and after 1-2 minutes turns off due to overheating.
• 🌡️ The condenser heats up unevenly (one part hot, the other cold).
• 🕳️ In the freezer, a “snow cap” may form at the entrance of the capillary tube.

How to check:

1. Turn off the refrigerator and defrost it.
2. Find capillary tube a thin copper tube going from the filter-drier to the evaporator.
3. Check the temperature of the tube:
   • ✅ Normal: after For 10 minutes of compressor operation, the tube should be warm at the inlet and cold at the outlet.
   • ❌ If clogged: the tube is uniformly cold or hot.

Inspect filter drier (the metal cylinder on the tube If it is blackened, replacement is required.

On models with Smart Diagnosis freon leak may be displayed as an error "ER RF" or "Refrigerant Leak". In this case:

• Do not turn on the refrigerator - this may damage the compressor.
• Contact the service center LG to find a leak and refuel.

Repair cost for a freon leak:

7. Diagnostics of the fan and cooling system

In refrigerators LG with a system No Frost the fan is responsible for air circulation. If it does not work, the refrigerator compartment will not cool well, and the freezer compartment will freeze.

Signs of a fan malfunction:

• 🔇 The refrigerator has become quieter than usual (the fan does not make noise).
• ❄️ There is a build-up in the freezer compartment ice, and heat in the refrigerator.
• 🌬️ There is little or no air flow from the vents.

How to check the fan:

1. Unplug the refrigerator.
2. Remove the back panel of the freezer cameras.
3. Find the fan - this is a plastic impeller with a motor.
4. Check:
   • 🔄 The blades should rotate freely (without jamming).
   • 🔌 Ring the motor winding - the resistance should be 200–500 Ohm.
   • 🔋 Apply voltage to the fan 12 V (from the power supply) - it should spin up.

If the fan does not work, the reasons may be be:

• 🔌 Wiring break (check the circuit from the board to the fan).
• 🛠️ Bearing wear (the fan hums, but does not rotate).
• ❄️ Icing of the blades (defrost refrigerator).

On models with Smart ThinQ fan malfunction is displayed as an error "ER FF". In this case:

1. Defrost the refrigerator for 24 hours.
2. Check whether ice is blocking the blades.
3. If the problem persists, replace the fan (part cost: 1,500–3,000 rubles).

8. When to call a technician: signs of serious breakdowns

Not all faults can be fixed on your own. Contact the service center LGif:

• 🔥 Burn marks or swollen capacitors are visible on the control board.
• 💨 The refrigerator has stopped cooling, but the compressor is running non-stop (a freon leak is likely).
• ⚡ After switching on, the circuit breaker in the panel is triggered (short circuit in the compressor windings).
• 📵 The display shows an error "ER IF" or "ER CM", and resetting does not help.

Cost of repairs in service centers LG (approximately):

Breakage	Cost (rub.)	Warranty period
Replacement compressor	12 000 – 20 000	1 year
Repair of control board	3 000 – 8 000	6 months
Elimination of freon leakage	5 000 – 12 000	1 year
Replacement of heating element defrost	2 500 – 4 000	6 months

How to choose a service center:

• 🔍 Check whether the center has a certificate from LG (official partners use original spare parts).
• 📄 Check whether the work and parts are guaranteed (minimum 6 months).
• 💰 Compare prices: in unofficial workshops, repairs may cost less, but without a guarantee.

If the refrigerator is under warranty, do not disassemble it yourself! This will result in loss of warranty. Contact an authorized service center LG by phone 8-800-200-77