What it means
LG Canada's split system chart says 'Indoor unit return air thermistor has disconnected or has shorted out.' LG's US page for portable and window units pairs CH01 with E2 but describes it as an indoor pipe sensor fault, so the two LG sources disagree on which sensor it is. That page also says there is no homeowner fix on those units.
What to check, in order
- Reset the power
Unplug the unit or switch off its breaker, wait about 5 minutes, then switch it back on and see if the code clears.
- Stop using it if it returns
LG says that if the same code comes back after a reset, stop using the unit and request service to prevent further damage.
When to call an engineer
LG lists a faulty sensor, a loose or disconnected sensor, a main circuit board error or a temporary electrical problem as possible causes. A technician needs to test the sensor and its connection.
A repair visit will usually check the sensor's reading and its wiring.
- Note the model and serial number. They're on a label on the side of the indoor unit, and on the outdoor unit.
- Write down the exact code, and what the appliance was doing when it appeared.
- Check whether it's still under warranty. If it is, the repair may cost you nothing.
Quick answers
What does the LG CH01 error code mean?
The sensor that measures the air coming back into the indoor unit has disconnected or shorted out, so the unit has stopped. LG Canada's split system chart says 'Indoor unit return air thermistor has disconnected or has shorted out.' LG's US page for portable and window units pairs CH01 with E2 but describes it as an indoor pipe sensor fault, so the two LG sources disagree on which sensor it is. That page also says there is no homeowner fix on those units.
Can I fix LG CH01 myself?
Engineer only (engineer visit). Start with: reset the power; stop using it if it returns. LG lists a faulty sensor, a loose or disconnected sensor, a main circuit board error or a temporary electrical problem as possible causes. A technician needs to test the sensor and its connection.
Is LG CH01 worth repairing?
Worth fixing. Usually a sensor or its plug, which is a fairly small repair for a technician.
Checked against
- LG Canada: Single / Multi-Split Air Conditioner Error Codes
- LG USA: How to troubleshoot error codes CH01, CH02, CH06, CH12, CH41 to CH48, E1, E2, E3, E7, E8, F2, F3, CH21, CH23, CH26, CH29 and E9
- LG USA: Room air conditioner (portable, window, through-the-wall) error codes
Last reviewed October 2026. Manufacturers update their pages, and your manual is the final word. Spotted a mistake? Email contact@appliance-error-codes.com.