C1 error code LG air conditioner

The C1 error indicates that there is an error with an open or closed circuit for the indoor temperature sensor of your air conditioner.

The temperature sensor or thermistor is an integral part of how your air conditioner measures the ambient and cooling temperature of your room.

When your LG air conditioner is displaying “C1” error code, this indicates that there is a problem with the thermistor of your indoor unit, for which you can contact a professional, or investigate and fix yourself.

What does a temperature sensor do?

The temperature sensors of your air conditioners are used to measure the ambient temperature of the air in your space. This helps your air conditioner figure out how close it is to cooling down the temperature in your room to the desired temperature that you have selected.

The most common type of temperature sensor used in air conditioners is called a thermistor and it uses resistance to communicate with the computer which controls the heating and cooling functions of your air conditioner.

C1 error code LG air conditioner

LG is one of the leading manufacturers of air conditioners, but this does not mean that LG air conditioners are faultless or indestructible.

LG air conditioners are manufactured to display specific error codes when there is an issue with one of the unit’s components, electrical systems, or any other part of the air conditioner, so that you can identify the problem and fix it yourself, or even contact a professional for a repair service if necessary.

The C1, CH01, or E2 error codes are all indicative of an issue with an open or short circuit for the indoor pipe sensors on your air conditioner.

This is an auto-stop protection error, which means that your air conditioner stops automatically when this error occurs, and it will not switch on again until the error is cleared to protect you and your home.

LG recommends that you contact a professional in order to clear this error message from your display, but savvy DIY-experts have devised ways that you can investigate and safely try to clear this error yourself, by following these steps:

  • Step 1: Check the sensor for poor connections
  • Step 2: Check if the sensor is broken or short
  • Step 3: Check if the sensor has the correct resistance

By working through these troubleshooting solutions, you will be able to determine and maybe even fix the problem with the thermistor of your LG air conditioner.

You may also need a screwdriver to unscrew panels so that you can access the thermistor, PCB board, and other components during this process.

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Check the sensor for poor connections

Your first step when you are investigating the C1 error for your LG air conditioner should be to determine whether the indoor temperature sensor is just loose or if it is disconnected. You should also make sure that your air conditioner is unplugged before you start with this process.

Then, you can remove the front cover, air filters, and any other service panels, until you can see and access the thermistor and the PCB board.

Make sure that the thermistor is connected to the PCB board of your air conditioner and that there are no loose or frayed wires. If it looks like the wires are loose or disconnected, tighten and reconnect them before you try to switch your unit on again.

Check if the sensor is broken or short

Check whether the sensor has been damaged in any way. This could be causing a short circuit, which is why your air conditioner will be displaying the C1 error code and why it cannot continue to operate safely.

Common damages to this type of sensor include frayed wires, broken components, rusted or corroded wires and components, and in some cases, the thermistor could even be cut off completely.

This will result in an open or short circuit, which can be dangerous and the sensor should be replaced as soon as possible to avoid any damage and to ensure that you can continue to use the air conditioner as usual.

Check if the sensor has the correct resistance

If there are no visible signs of damage or a bad connection on the thermistor assembly, your last step in the investigation is to determine whether the sensor has the right resistance and is working correctly, using:



You can then place the tip of the thermistor into the cup of ice water to take a resistance reading. If this reading does not correlate to the resistance that is specified in your user manual, your thermistor needs to be replaced.

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