LG Heat Pump Error Code E410

E410 indicates an OPEN or SHORT circuit fault in the discharge temperature sensor for fixed capacity compressor 3 on the outdoor unit. The system detects this error when outdoor temperature is above -10°C and the sensor voltage reads above 4.95V (suggesting an open circuit at around -30°C) or below 0.5V (suggesting a short circuit at around 151°C). The heat pump shuts down the affected compressor to prevent damage until the fault is resolved.

Running the system with an active E410 code is not recommended. The error means compressor 3 lacks a functioning discharge temperature sensor, so the unit cannot protect that compressor from overheating during operation. Continued use could cause compressor damage, which is a far more costly repair than addressing the sensor fault.

Repair costs vary depending on the cause. If the fix is simply reseating a loose connector, the cost is limited to a service call fee, typically in the range of $80 to $150. If the discharge temperature sensor itself needs replacement, parts and labor combined generally range from $150 to $350. If the outdoor PCB is at fault, costs can rise significantly, often falling between $400 and $800 or more depending on the unit model and labor rates in your area.

A homeowner can safely check whether the sensor connector is visibly loose or disconnected at the outdoor PCB and reseat it if needed. However, measuring sensor resistance, tracing wiring faults, and replacing components on the refrigerant circuit board requires technical knowledge and appropriate tools, so a qualified HVAC technician should handle those steps. Working inside the outdoor unit also involves exposure to line voltage, so caution is essential.

A power reset may temporarily clear the error display, but E410 will return if the underlying sensor fault is still present. The system continuously monitors sensor voltage, and once it detects the out-of-range reading again, it will re-trigger the fault code. The root cause, whether a disconnected connector, failed sensor, or wiring issue, must be corrected for the error to clear permanently.