Samsung Heat Pump Error Code E401

E401 indicates that the condenser outlet (COND OUT) temperature sensor has been detected as detached, defective, or unable to read properly during heating operation. The sensor monitors refrigerant temperature at the condenser outlet, and the control board triggers this fault when the signal falls outside the expected range. The most common cause is the sensor physically separating from its mounting clip or holder.

A reset may temporarily clear the fault display, but the error will return if the underlying problem has not been resolved. If the sensor is physically detached, reseating it before resetting gives the repair a good chance of holding. If the sensor is defective, resetting alone will not prevent the fault from recurring.

If the fix is simply reseating a loose sensor, there may be no parts cost at all, though a service call to diagnose and perform the repair typically runs in the range of $75 to $150 depending on your region and provider. If the COND OUT sensor itself is defective and requires replacement, parts and labor combined generally fall in the range of $100 to $300. Costs can be higher if a refrigerant flow restriction is identified as the underlying cause.

Start by powering down the unit and inspecting the COND OUT sensor and its holder to confirm the sensor is fully seated and the holder is securely clipped in place. If the sensor has come loose, reinsert it firmly and restart the system. If the fault returns after reseating the sensor, the sensor itself may need resistance testing to determine whether it has failed and requires replacement.

It is not recommended to continue operating the unit while this error is active. The COND OUT sensor data is used by the control board to protect the compressor and manage heating operation safely. Running the system without a reliable sensor reading can lead to uncontrolled operating conditions that may cause further component damage.