Outdoor Air Temperature Sensor
LG CH44 Error Code
The LG CH44 error code shows when the outdoor unit can no longer read the sensor that measures the temperature of the outside air. LG uses that reading to plan defrosting, fan speed and compressor limits, so the system stops when it disappears. Here is a clear guide to the cause, the checks and the repair.
Explained
What Is the LG CH44 Code?
Every LG outdoor unit has a small sensor that measures the temperature of the air flowing into it. It is usually mounted on a bracket near the back of the outdoor coil, where it samples air before the unit warms or cools it. It does the same job outside that the room sensor does inside.
CH44 appears when the board reads a value from this sensor that falls outside what is physically possible. LG service information describes it as the outdoor unit inlet air thermistor being open or short circuited. Put simply, the outdoor air sensor has stopped giving a believable number.
Like other sensor codes, CH44 does not mean the compressor or refrigerant circuit is damaged. It means the board has lost an input it relies on. The system shuts down because running without that input would risk poor or unsafe operation, particularly in extreme weather.
Owners sometimes think the code is triggered by a genuinely extreme day. That is not the case. A very hot or very cold day is still within the sensor’s reading range. CH44 is about the sensor failing, not about the weather itself being too harsh.
What It Controls
Why Does LG Need to Know the Outdoor Temperature?
The outdoor air reading feeds into a surprising number of decisions. Losing it affects the system in several ways at once.
Defrost Timing in Heating
In winter heating, the outdoor coil gets colder than the air around it and can frost over. The board compares the outdoor air temperature with the coil temperature to decide when to run a defrost cycle. Without the air reading, it cannot judge this properly.
Outdoor Fan Speed
On mild days the outdoor fan can slow down to save energy and reduce noise. On hot days it needs to run faster. The air reading helps set the right speed.
Compressor Limits
The board limits compressor speed in very hot or very cold weather to protect it. The outdoor temperature is one of the inputs for those limits.
Display and Smart Features
Some LG models and apps show the outdoor temperature or use it for energy features. Those stop working accurately when the sensor fails.
Reading the Code
How Does CH44 Appear on My LG?
On models with a number display, you will see CH and 44 on the indoor unit. On lights only models, a blink pattern repeats, often using two indicator lights to show the two digits. Ducted systems show CH44 on the wired controller.
Because the code comes from the outdoor board, the indoor unit only shows it once communication has been established. If the system was working normally and then stops with CH44, the sensor has likely failed or lost contact during operation.
Some owners notice a related symptom before the code appears. In heating mode, the system may run unusually long defrost cycles or skip them, leaving the outdoor coil heavily iced. That can be a sign of a sensor that is drifting before it fails completely.
Open more detail
Some code lists online give CH02 as the outdoor air sensor. That belongs to older or different equipment. On current LG residential splits, CH02 is the indoor coil inlet sensor and CH44 is the outdoor air sensor. The technician will confirm the meaning for your specific model, especially for multi split, commercial or older units.
Ranked Causes
What Makes the LG Outdoor Air Sensor Fail?
The outdoor air sensor is directly exposed to the weather on many units. That makes it more vulnerable than sensors hidden inside the casing.
Easier Causes
- A temporary glitch after a power interruption
- The sensor knocked off its bracket by debris or garden work
- A loose plug on the outdoor board
- Water sitting on the plug after heavy rain
Harder Causes
- The sensor bead cracked by years of sun and weather
- A lead damaged by pests, whipper snippers or sharp metal
- Corrosion on plug pins from salt air
- A failed sensor input on the outdoor board
Garden maintenance deserves a special mention. Line trimmers, hedge cutters and leaf blowers used close to an outdoor unit can throw debris into the coil area, and the outdoor air sensor sits right where that debris lands. A sensor that was fine yesterday can be dislodged in seconds.
Your Checks
What Can I Safely Look At for CH44?
You can look at the outside of the outdoor unit and its surroundings. Do not reach into the coil area, pull on any wires or remove panels.
- Photograph the code on the indoor display or controller.
- Switch off at the remote and then at the breaker. Wait five minutes, then restore power.
- From a safe distance, look at the back of the outdoor unit for a small sensor hanging loose on its lead or knocked out of position. If you see one, do not touch it, but mention it when you book.
- Remove leaves, grass clippings and other debris from around the outdoor unit by hand, keeping clear of the coil fins.
- Check that sprinklers are not spraying directly onto the unit.
- Restore power and test once.
If the code returns, switch off at the breaker and book a technician. A dangling sensor is a quick fix for a technician, but it needs the power isolated.
Using the System
Is It Safe to Keep Running My LG With CH44?
Most LG units will stop the compressor while CH44 is active. Some may run in a limited way. Either way, it is wise to leave the system off until the sensor is repaired.
In heating mode, the main risk is poor defrost control. Without the outdoor air reading, the coil can ice up badly, which reduces heating and puts stress on the outdoor fan and coil. In cooling mode, the board may not set fan speed and compressor limits correctly on very hot days.
The fault itself is low risk in terms of damage, and the repair is usually simple. Leaving the system off while you wait keeps it that way.
Repair Process
How Does a Technician Fix LG CH44?
The repair is normally one of the simpler outdoor jobs. The technician still follows safe isolation procedures, because the sensor plugs into the inverter board area.
Isolate the Unit
Power is isolated at the outdoor unit and the board is allowed to discharge before covers come off.Find the Sensor
The technician locates the outdoor air thermistor, usually on a bracket near the rear of the coil, and checks it is in its correct position.Inspect the Lead and Plug
The lead is followed back to the board, checking for cuts, chewing, weather damage and corrosion at the plug.Measure Resistance
The thermistor is tested and its resistance compared with the expected value at the current air temperature.Check the Board Input
If the sensor is fine, the board’s input voltage is checked to see whether the board is at fault.Replace and Secure
A new sensor is fitted to its bracket and the lead routed and tied clear of moving parts and sharp edges.Test in Operation
The system is run and the outdoor temperature reading checked against actual conditions.
Winter Heating
Why Is CH44 More Noticeable in Winter?
Owners often meet CH44 for the first time on a cold morning. There are good reasons for that. Heating mode relies heavily on the outdoor air reading to manage defrosting. A sensor that is drifting may get away with it in cooling season, then fail once the board starts asking more of it.
Cold, damp nights also bring condensation and dew onto outdoor parts. Water collecting on a damaged lead or corroded plug can tip a marginal sensor into a full fault. As the morning warms and things dry out, the code may clear, only to return the next night.
If your CH44 follows that pattern, appearing on cold mornings and clearing later in the day, mention it when you book. It points strongly towards moisture getting into the sensor or its connection.
What Happens to Defrost Without the Air Reading?
During heating, a reverse cycle system pulls heat out of the outdoor air. On cold, humid nights, moisture in that air freezes onto the outdoor coil. A layer of frost acts like a blanket, cutting the coil’s ability to absorb heat. Every so often, the system must briefly reverse to melt it off.
Knowing when to start and stop that defrost depends on comparing coil temperature with air temperature. Too few defrosts and the coil ices solid. Too many and the home loses warmth while the system wastes energy. With the air reading gone, LG plays it safe and stops rather than guessing. That is frustrating on a frosty morning, but it protects the outdoor coil and fan from heavy ice damage.
Owners in cooler climates, and in inland areas where frosty mornings are common, tend to notice this most. A prompt sensor repair restores normal, efficient defrosting.
While you wait for the repair, a portable heater or extra layers may be needed on cold days. Avoid repeatedly switching the air conditioner on and off in the hope it will start heating again. That will not bypass the protection, and it adds needless wear to relays and the compressor drive. Leave it off at the breaker and wait for the technician instead, keeping a note of any changes you see.
Climate Factors
How Does the Australian Climate Affect the Outdoor Sensor?
Sunlight is a big factor. Ultraviolet light breaks down plastic and rubber over time, and an outdoor sensor lead exposed to strong sun can become brittle and crack. Units on north and west facing walls see the strongest exposure.
Coastal homes face salt. Salt settles on the sensor and its plug and draws in moisture, speeding up corrosion. Inland areas can see dust coating the sensor, which can slightly affect readings and hold moisture against the lead.
Storms bring two risks. Power disturbances can cause temporary sensor errors that clear with a reset. Strong winds can blow debris against the back of the outdoor unit and knock the sensor out of place. Hail can damage the coil and anything mounted on it in severe events.
Protecting It
How Do I Reduce the Chance of CH44?
A tidy, well positioned outdoor unit is the best protection for its sensors.
Careful Garden Work
Keep line trimmers and blowers well away from the outdoor unit. Pull weeds near the unit by hand instead.
Keep the Back Clear
Leave clear space behind the unit. Plants, fences and stored items close to the coil trap debris and moisture around the sensor.
Service Inspections
During routine servicing, ask the technician to check the outdoor sensors and leads while the unit is open.
A Typical Visit
What Does a Typical CH44 Repair Look Like?
Many CH44 calls are resolved in a single visit. A common story starts with a homeowner who has had a gardener in, or who has trimmed the hedge beside the outdoor unit. The next time the system runs, it stops with CH44.
On arrival, the technician finds the sensor hanging loose from its bracket or with a nicked lead. If the sensor itself is undamaged, it is refitted and secured. If the lead is cut or the bead is cracked, a replacement sensor goes in. Either way, the system is usually back in action the same day.
Other visits take a little longer. If corrosion has spread into the plug on the board, or if the board input has failed, more work is needed. The technician will explain the findings and options before going further.
What Should I Have Ready?
Have the model number of the outdoor unit, a photo of the code, and a note of any recent garden work, storms or pest activity. If the outdoor unit is hard to reach, such as on a roof or high bracket, let us know when you call.
Related Codes
Which Codes Are Related to LG CH44?
These sibling pages cover other LG sensor codes and outdoor faults that often come up in the same conversations.
LG CH01
The indoor room air sensor, the indoor counterpart of CH44.
LG CH41
The discharge pipe sensor, another outdoor thermistor.
LG CH67
The outdoor fan motor, whose speed depends partly on outdoor temperature.
For the full set, visit the LG error codes hub, or explore the wider error code library.
Getting a Technician Out
Who Can Fix an LG CH44 Code in My City?
We arrange licensed technicians for LG outdoor sensor faults in Sydney, Melbourne, Brisbane, Perth and Adelaide. Pick your city for local information.
Melbourne
Cold mornings that test defrost control.
Adelaide
Hot, dry summers and chilly winter nights.
Perth
Strong sun that weathers outdoor parts.
Rapid Air Cooling is a booking service and is not affiliated with LG. The technicians we send hold the licences their work requires.
Questions
Frequently Asked Questions
Does a very hot day cause CH44?
No. Extreme weather is still within the sensor’s range. CH44 means the sensor reading is missing or impossible, not that the day is too hot or cold.
Can I push a loose outdoor sensor back into place?
Please do not. It sits near the coil and is wired to the inverter board. A technician should refit it with the power isolated.
Why does CH44 only appear on cold mornings?
Moisture from dew or condensation can upset a damaged lead or corroded plug. As things dry out, the code clears. A technician can find the weak point.
Is CH44 expensive to fix?
Usually not. Most repairs involve refitting or replacing the sensor. A board input fault is a larger job and you will be told before any work.
Will heating work without the outdoor sensor?
Generally no. The board needs the outdoor reading to manage defrosting safely, so it stops or limits heating until the sensor is fixed.
Could my gardener have caused CH44?
It is possible. Trimmers and blowers used near the outdoor unit can dislodge or cut the sensor lead. Mention any recent garden work when you book.
Where can I learn more?
Our troubleshooting guide covers everyday issues, and our page on air conditioning service Australia explains how bookings work.
LG Showing CH44?
Give us a call with the code and we will arrange a licensed technician to test and refit the outdoor air sensor so your system can read the weather again.
Reviewed by AC repair and service specialist on 22 October 2026. How we write our articles