LG Heat Pump Error Code qx

The Qx error code on an LG heat pump indicates an open circuit or short circuit in the room temperature sensor of the indoor unit identified by the address number following the Q. The system uses this sensor to measure ambient room temperature and control operation. When the sensor signal falls outside acceptable resistance limits, the unit faults out and displays this code to prevent inaccurate climate control.

The system will typically suspend normal operation when this fault is active, so continued use is often not possible without clearing the fault. Even if the unit were to continue running, operating without a valid room temperature reading would cause it to heat or cool inaccurately. It is best to address the sensor fault before resuming regular use.

A power reset may temporarily clear the fault display, but the Qx code will return as soon as the system attempts to read the sensor again and detects the same open or short condition. The underlying sensor or wiring issue must be physically corrected for the fault to clear permanently. Repeated resets without addressing the root cause will not restore normal operation.

A knowledgeable DIYer can perform initial checks such as reseating the sensor connector and inspecting the wiring for visible damage. Testing the thermistor requires a multimeter to measure resistance across the sensor terminals. If the sensor itself has failed or wiring needs replacement, those repairs are generally straightforward, but working inside the indoor unit requires safely powering down the system first and having some comfort with electronics and wiring.

If only the sensor needs replacement, parts typically cost in the range of $15 to $60 depending on the specific indoor unit model. Adding professional labor for diagnosis and replacement, total repair costs generally fall in the range of $100 to $300. If the PCB is the root cause, costs will be significantly higher due to the price of the board itself.