LG Heat Pump Error Code E158

E158 is an electric heater discharge temperature protection error. It means the control board detected that the temperature at the discharge point of the electric auxiliary heater exceeded the safe operating limit and shut the heater down as a protective measure. This code can result from restricted airflow, a faulty temperature sensor, or a malfunctioning heater component. A technician should inspect the system before restoring normal operation.

Yes, this error represents a real safety protection event. The system shut down the electric heater because temperatures reached an unsafe level, which if left unaddressed could risk damage to internal components or create a fire hazard. Do not disable or bypass the protection circuit. Have a qualified technician diagnose and repair the fault before returning the system to full operation.

Clearing or resetting the code without addressing the underlying cause will not fix the problem. The error will return once the heater runs again and the same fault condition is detected. Permanent resolution requires identifying and correcting the specific cause, whether that is improving airflow, replacing a faulty sensor, or repairing the heater circuit.

You can attempt a reset by powering the unit off at the breaker for several minutes and then restoring power, but if the underlying cause is not corrected the error will return. Before resetting, check that your air filter is clean and that all supply and return vents are open and unobstructed. If the error comes back immediately or the unit repeatedly faults, the system needs professional inspection to identify the root cause.

Repair costs vary depending on the cause. If the fix is simply replacing a dirty filter, costs are minimal, typically under $30. A replacement discharge temperature sensor can range from $20 to $80 for the part, plus labor. A faulty heater relay or heater element replacement including parts and labor may range from $150 to $500 or more depending on the model and service rates in your area.