LG Mini-Split Error Codes — CH01 Through CH67 Diagnosis Guide
LG mini-splits display 'CH' (check) codes when a fault is detected — each code maps to a specific component or circuit. Models including the LS120HEV2, LMU36CHV multi-zone, LMN096HVT, and LAN090HYV4 share a largely common error code system. Many CH codes can be cleared by the homeowner with basic tools; others require a technician with gauges and inverter diagnostic equipment. This guide covers every major LG mini-split error code with diagnosis steps, starting with the most common and DIY-accessible.
Try the AI Diagnosis ToolAI Repair Tools
Common Symptoms
- CH error code on the indoor unit display or LG ThinQ app
- Indoor unit running but no cooling or heating output
- Outdoor unit not running when indoor unit is calling for conditioning
- Unit repeatedly cycles on and trips the same CH error code
- LG ThinQ app shows fault history with CH codes and timestamps
Most Likely Causes
- 1
CH01 — Indoor Temperature Sensor Fault
CH01 means the indoor air temperature thermistor (room temperature sensor) has failed or is reading out of range. This sensor is typically a small NTC thermistor on the indoor PCB or on a lead wire near the return air intake. A failed sensor prevents the unit from determining room temperature, disabling normal operation.
- 2
CH02 — Indoor Coil Temperature Sensor Fault
CH02 indicates the indoor heat exchanger (coil) thermistor has failed. This sensor controls freeze protection and over-heat protection. A severely dirty filter can cause coil temperature to drop out of range, triggering CH02 without an actual sensor failure — always clean filters first.
- 3
CH03 / CH10 — Communication Fault (Indoor-to-Outdoor)
CH03 = communication error between indoor and outdoor units on the low-voltage control circuit; CH10 = outdoor communication fault (PCB or wiring issue at the outdoor unit specifically). Check the communication wire terminals at both units and inspect the wire for damage.
- 4
CH05 — Indoor Fan Motor Lock
CH05 means the indoor cross-flow fan motor has stalled or is drawing excessive current. Causes: debris in the fan wheel, fan blade cracked or loose on the motor shaft, or failed motor bearing. Inspect the fan wheel for obstructions before replacing the motor.
- 5
CH38 — Inverter PCB or Compressor Protection Fault
CH38 on LG mini-splits typically points to the inverter PCB (EBR81363109 or similar) or a compressor protection trip. This is one of the more serious codes — it can indicate an inverter component failure, a short in the compressor windings, or a refrigerant-related high/low pressure event that triggered inverter protection.
- 6
CH67 — Outdoor Fan Motor Fault
CH67 indicates the outdoor fan motor has stalled, locked up, or is drawing current outside the expected range. The outdoor fan is critical to heat rejection — a failed outdoor fan will cause high-pressure trips on the refrigerant circuit and rapid loss of cooling or heating capacity.
Not sure if this is the right fix for your exact model?
Upload a photo of your appliance label — Fix-It Fast AI will identify your exact unit and tailor the diagnosis.
Quick DIY Checks
LG mini-splits operate on 208/240V single-phase circuits. Always turn off the circuit breaker and the outdoor disconnect before accessing the indoor control board, outdoor control board, or any wiring. Verify power is absent with a non-contact voltage tester before touching any terminals.
Do not attempt to handle refrigerant, access refrigerant service ports, or test compressor pressures without EPA 608 certification. LG mini-splits use R-410A refrigerant at high pressures. Refrigerant diagnosis requires manifold gauges and proper certification.
When accessing the indoor coil for cleaning, keep water and coil cleaner foam away from the PCB control box at the right end of the indoor unit. Water intrusion into the control box causes additional faults and board corrosion.
The LG Art Cool panel (LAN090HYV4) is a glass or acrylic decorative cover that can crack if forced. Release both bottom tabs simultaneously before pulling the panel — do not pry or use tools to remove it.
- 1Open the LG ThinQ app (on smartphone) and connect to your mini-split if registered. Navigate to Diagnostics → Error History. This shows the full CH code history with timestamps, which helps confirm whether the code is intermittent or persistent. Also check the current sensor readings if your model supports them (LMN096HVT and LAN090HYV4 expose more data in ThinQ).
- 2For CH01 or CH02: remove and clean the indoor air filters first. On LS120HEV2, lift the front panel and pull the mesh filters out from each side. Rinse under running water, dry fully, reinstall. Then cycle power at the breaker for 60 seconds. A dirty filter causing coil freeze will often trigger CH02 as a secondary symptom — filter cleaning alone resolves it.
- 3For CH03 or CH10: inspect the communication wire connecting the indoor and outdoor units. On LG systems this is typically a 3-conductor cable in the same conduit as the power wires. At the outdoor unit terminal block, locate the terminals labeled 1, 2, 3 (or S1, S2, S3). Confirm each wire is secure with no loose strands. Tighten terminal screws and reset power. Also confirm the outdoor unit's 240V circuit breaker is on.
Get the full fix — Pro members get unlimited AI diagnoses
Save your repair history, get step-by-step AI guidance on any HVAC & cooling issue, and avoid $150+ service call fees.
Try Pro — $7.99/mo- 4For CH05: power off the unit at the breaker. Open the indoor unit front panel and visually inspect the cross-flow fan (a long cylindrical fan wheel running the width of the unit). Look for leaves, dust clumps, or foreign objects jammed in the blades. Spin the fan wheel by hand — it should rotate freely with no grinding or resistance. If it's obstructed, clear it. If it grinds or has excessive resistance, the motor bearing has failed.
- 5For Art Cool models (LAN090HYV4): the Art Cool panel is a flat decorative front that snaps off before accessing the filters and indoor coil. Depress the two release tabs at the bottom corners of the art panel and pull it straight forward. Behind it is the standard indoor unit with mesh filters. Perform filter cleaning and coil cleaning with no-rinse foam before diagnosing any error code.
- 6For CH38: cycle the breaker off for 5 minutes (not just 60 seconds — the inverter capacitors need time to fully discharge). Restore power and attempt to start in COOL or HEAT mode. If CH38 returns immediately, the fault is likely in the inverter PCB (EBR81363109) or compressor. Measure the AC supply voltage at the outdoor disconnect — CH38 can be caused by voltage supply issues. If voltage is correct (208–240V), contact an LG-authorized HVAC technician for inverter board testing with proper diagnostic equipment.
Save $150+ on a single service call
Less than a cup of coffee — fix it yourself with expert guidance.
- ✓ Step-by-step repair guides with exact part numbers
- ✓ Expert diagnosis in seconds — 500+ problems covered
- ✓ Full tool list & cost estimate before you spend a dime
$150+ service call vs. $7.99/mo · Cancel anytime
Repair vs Replace
Most LG CH codes point to sensors ($15–$40), fan motors ($60–$200), or communication wiring — all repair-friendly. CH38 with a confirmed inverter PCB failure costs $150–$400 in parts. Consider replacement only if the Dual Inverter Compressor has mechanically failed on a unit over 10–12 years old.
Est. Repair Cost
$0–$500 DIY (filter clean, sensor replacement, communication wire, fan motor)
Est. Replacement Cost
$2,000–$6,000 installed for a new LG multi-zone or single-zone system
Recommended Tools & Parts
- Buy on Amazon →
LG Mini-Split Inverter PCB EBR81363109
Replacement inverter control board for LG mini-split outdoor units. Required when CH38 persists after power cycle and voltage supply is confirmed correct. Match part number to your specific outdoor unit model — verify on the unit's rating label before ordering.
$150–$400
- Buy on Amazon →
LG LS120HEV2 Indoor Temperature Sensor (CH01 repair)
Replacement NTC thermistor for LG mini-split indoor air temperature sensing (CH01 error). Test existing sensor resistance at room temperature (~10–15kΩ typical) before replacing. A reading of OL or near-zero confirms failure.
$10–$30
- Buy on Amazon →
LG LMN096HVT Indoor Coil Thermistor (CH02 repair)
Replacement indoor heat exchanger thermistor for LG mini-split CH02 error. Required after confirming CH02 persists after filter cleaning and power cycle.
$10–$30
- Buy on Amazon →
LG Indoor Cross-Flow Fan Motor (CH05 repair)
Replacement cross-flow fan motor for LG LS120HEV2 and LMN096HVT indoor units. Test motor windings before replacement. Required when CH05 persists after clearing fan wheel obstructions.
$60–$180
- Buy on Amazon →
LG Mini-Split Communication Wire (3-conductor, 18 AWG)
Replacement 3-conductor communication wire for LG indoor-to-outdoor control circuit. Required when CH03 or CH10 is caused by damaged wiring. Verify run length before ordering.
$10–$25 per 50 ft
Links are Amazon affiliate links (tag: fixitfastai-20). Prices are estimates.
Still stuck? Let AI take a look.
Describe your problem or upload a photo — get a diagnosis in seconds.
Related Repairs
Senville Mini-Split Error Codes — E0 Through F6 Complete Guide
Senville mini-split showing E0, E1, E4, E5, or F-codes? This guide decodes every Senville error code for SENL-09CD, SENA-18HF/Z, LETO, and AURA Series.
Read guide →LG Window AC Not Cooling
LG window AC running but not cooling? Check Energy Saver mode, filter indicator, error codes E1 and CH, and condenser fins before calling a tech.
Read guide →Goodman Furnace Blink Codes: 1–9 Flashes — What Each Code Means & How to Fix
Goodman or Amana furnace LED flashing? Count the flashes: 3 = pressure switch, 4 = high limit, 6 = ignition failure. Full code list, diagnosis steps, and lockout reset procedure.
Read guide →Carrier Furnace Blink Codes: 13, 14, 24, 31, 33 — How to Read & Fix
Carrier or Bryant furnace LED flashing? How to read dual-LED fault codes, plus full code guide: 13 (limit lockout), 14 (ignition lockout), 24 (blown fuse), 31 (pressure switch open), 33 (limit rollout lockout).
Read guide →Save $150+ on a single service call
Less than a cup of coffee — fix it yourself with expert guidance.
- ✓ Step-by-step repair guides with exact part numbers
- ✓ Expert diagnosis in seconds — 500+ problems covered
- ✓ Full tool list & cost estimate before you spend a dime
$150+ service call vs. $7.99/mo · Cancel anytime
Still not sure what's wrong?
Get an AI diagnosis in seconds — describe the problem or upload a photo.
Get an AI Diagnosis⚡ Get step-by-step help for YOUR specific appliance
Our AI diagnoses your exact model — not just generic advice. Upload a photo or describe the issue and get a repair plan in seconds.
No account needed for diagnosis. Cancel Pro anytime.
Related Tools
Frequently Asked Questions
- What is LG's LGRED Heat Technology and what error codes are specific to it?
- LGRED (Low Ambient Heating with Enhanced Defrost) is LG's cold-climate heat pump technology, available on models like the LMU36CHV and LAN090HYV4. It maintains full 100% heating capacity down to 5°F and delivers heat output down to -13°F ambient. Error codes specific to LGRED operation: CH38 is more common on LGRED units at extreme cold temperatures because the inverter works harder, increasing thermal stress on the IPM board. CH67 outdoor fan motor faults can occur in ice-over conditions when the fan motor stalls trying to push air through a heavily frosted outdoor coil — the unit should defrost automatically, but severe icing from restricted airflow or refrigerant issues prevents full defrost. If CH codes occur specifically during very cold weather, confirm outdoor unit clearance (18+ inches on all sides) and that drainage from the unit is not backing up and re-freezing.
- How do I use the LG ThinQ app to diagnose my mini-split error codes?
- The LG ThinQ app (available for iOS and Android) provides remote diagnostics for LG Wi-Fi-enabled mini-splits. To use it: (1) Ensure your mini-split is registered in the ThinQ app. (2) From the main dashboard, select your mini-split. (3) Tap the three-dot menu or 'More' → 'Diagnostics' or 'Smart Diagnosis.' (4) The app will show current sensor readings (room temp, coil temp, fan speed) and error history with timestamps. The error history is particularly useful for intermittent CH codes — you can see if CH38 or CH02 occurred at a specific time and correlate it with conditions (extreme cold, power outage, etc.). Some LG models also support a phone-based Smart Diagnosis that transmits diagnostic data from the unit speaker to the ThinQ app microphone — useful if the Wi-Fi module is offline.
- What is the difference between LG's Dual Inverter Compressor and a standard inverter mini-split?
- Standard inverter mini-splits use a single-piston rotary compressor with a variable-frequency drive — speed varies but the basic compression mechanism is single-stage. LG's Dual Inverter Compressor (used in LMU36CHV, LMN096HVT, and LAN090HYV4) uses a twin-rotary compressor with two pistons offset 180 degrees. This reduces vibration significantly, allows a wider speed range (15–115 Hz vs. 30–90 Hz on standard inverters), and improves energy efficiency at part load. From a troubleshooting perspective: CH38 on a Dual Inverter system may indicate the inverter PCB (EBR81363109) or the twin-rotary compressor itself. A compressor winding test (resistance between terminals with power off) can help distinguish — an open winding OL indicates compressor failure; balanced winding resistance (typically 1–5Ω between terminals) suggests the inverter board is the fault.
- How do I remove the Art Cool panel on the LAN090HYV4 to access the indoor coil?
- LG Art Cool panels are decorative glass/acrylic front covers that attach with snap-tabs. To remove: (1) Power off the unit at the breaker. (2) Stand in front of the unit. The Art Cool panel has two release tabs at the bottom corners — press both inward simultaneously. (3) With both tabs depressed, pull the bottom of the panel toward you. The panel pivots from the top and detaches from the upper clips. (4) Do not force it — if resistance is felt, check that both tabs are fully depressed before pulling. Behind the Art Cool panel is the standard indoor unit housing with mesh filter access. Do not bend, flex, or drop the Art Cool panel — glass or acrylic panels crack easily. After servicing, align the top clips first, then press the bottom into position until both tabs click.
- LG mini-split CH38 — is it the inverter board or the compressor?
- CH38 on LG mini-splits can point to either the inverter PCB (EBR81363109) or the compressor. To distinguish them: (1) Turn off the breaker for 5+ minutes to allow inverter capacitors to discharge fully. (2) With power off, disconnect the three compressor leads from the inverter board. (3) Use a multimeter in resistance mode to test compressor winding resistance between each pair of terminals (T1-T2, T2-T3, T1-T3). A healthy compressor reads 1–5Ω between each pair and OL (open circuit) between each terminal and ground (compressor body). If any reading between terminals is OL, the compressor winding has failed — the compressor needs replacement, which is typically uneconomical on a residential mini-split. If compressor windings are balanced, the inverter PCB (EBR81363109) is the likely failure — replace the board.