LG Air Conditioner Error 4
⚡ Quick Answer: The LG air conditioner error 4 indicates a communication failure between the indoor and outdoor units, often linked to an exhaust temperature sensor m... ✅ DIY Fixable
What Does Error 4 Mean?
The LG air conditioner error 4 indicates a communication failure between the indoor and outdoor units, often linked to an exhaust temperature sensor malfunction. Symptoms include the unit not responding, stopping cooling or heating, and briefly running before shutting off. This error typically appears shortly after startup or during operation.
Common Symptoms:
- Error displayed shortly after startup or during operation
- Unit may stop cooling or heating when code appears
- System may run briefly then shut off
Possible Causes
- Exhaust temperature sensor fault or related sensor malfunction (medium)
How to Fix Error 4
DIY Fix Basic verification and restart
- Turn off the AC and disconnect power
- Wait for at least 5–10 minutes
- Reconnect power and restart the system to see if the code reappears
Technician Only Inspect and potentially replace temperature/exhaust sensor
- Access the internal sensors (exhaust/temperature thermistor) with power off
- Check sensor connections for corrosion or loose contacts
- Measure sensor resistance/response against expected values
- Replace the faulty sensor if readings are outside expected range
Parts needed: Temperature/exhaust sensor (thermistor), Associated wiring/connectors
- If error persists after power cycle and sensor inspection
- If multiple codes appear simultaneously
- If there are signs of electrical damage or burning smell
Next step
Choose the next step for 4
Confirm the diagnosis before ordering. An error code can identify the system involved, but it does not prove that a specific part has failed.
Most relevant component to inspect
Thermistor
Measures precise temperature changes and sends resistance feedback to the control board.
- Typical part-only price
- $15 - $35
- DIY difficulty
- Easy
- Estimated time
- 15-30 mins
Where can I find the model number?
Check the rating label around the door, lid, frame, rear panel, or inside the appliance cabinet. Use the complete model number, including suffixes.
Verify the complete model and part number on the retailer's compatibility page before ordering.
Other parts options
Check related components first; use model search as a fallback.
Wiring Harness
Connects controls, sensors, motors, and other electrical components inside the appliance.
Model-compatible Air Conditioner parts
Enter the complete model number to browse compatible replacement parts. This is a model-based parts search, not a diagnosis that a specific component failed.
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Optional routine care
Maintenance supplies
These products support cleaning or routine upkeep. They are separate from the possible repair components above and are not claimed to fix this error code or symptom.
Air Conditioner Fin Cleaner
For routine cleaning of accessible coil fins when permitted by the manufacturer. Disconnect power and follow product and appliance instructions.
Model-Compatible Washable AC Filter
A reusable filter option only where the appliance supports one. Match the full model, dimensions, and filter specification.
Compatibility check required: use the complete appliance model and compare the existing filter, bag, or specification before ordering.
Affiliate disclosure: As an Amazon Associate I earn from qualifying purchases. Recommendations are based on routine-care relevance, not commission rate.
Technical Specifications
| wattage | 2000W |
|---|---|
| component | Control Board |
| resistance | 10-20 ohms |
| part_number | LG 6711A20045B |
| voltage_rating | 220V AC |
Common Questions
What does 4 error mean on lg air conditioner?
Error 4 indicates a communication failure, often tied to a malfunctioning temperature sensor.
Can I fix lg air conditioner 4 error myself?
Yes, you can try restarting the unit by powering it off for 5-10 minutes.
How much does it cost to fix 4 error?
The estimated repair cost ranges from ¥5,000 to ¥25,000, depending on the region.
When should I call a technician for 4?
Call a technician if the error persists after a power cycle or if you notice multiple error codes.
Sources & References
Data last verified: 2026-07-26
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