LG Heat Pump Error Code E315

E315 indicates a high pressure sensor OPEN or SHORT error on an LG heat pump. The control board checks the sensor signal voltage just before the compressor starts, and flags this code if the voltage is below 0.4V (SHORT) or above 4.2V (OPEN). Both conditions mean the sensor is not producing a valid signal, so the unit prevents the compressor from running to avoid unmonitored operation.

The unit will not allow the compressor to start while E315 is active, which is a built-in protection measure. You should not attempt to bypass this protection. Operating a heat pump compressor without a functional high pressure sensor removes a key safeguard against dangerously elevated refrigerant pressures that can cause component failure or system damage.

Repair costs vary depending on the root cause. Replacing a high pressure sensor typically involves parts costs in the range of $30 to $120, plus labor. If the main control board is at fault, parts alone can range from $150 to $400 or more depending on the model. Wiring repairs or connector service are generally on the lower end of the cost spectrum. Getting a diagnostic visit from a qualified technician is the best way to get an accurate estimate.

Some aspects of diagnosing E315 are accessible to a knowledgeable DIYer, such as inspecting the wiring harness and connectors for visible damage, corrosion, or loose pins. However, testing sensor output voltage and replacing the high pressure sensor or control board involves working near refrigerant lines and electrical components, which is best handled by a certified HVAC technician. Refrigerant system repairs legally require EPA 608 certification in the United States.

A power reset may temporarily clear the error code, but if the underlying fault in the sensor or wiring is still present, the code will return as soon as the unit attempts to start the compressor again. A reset alone does not fix the root cause and is not a reliable solution for E315.