Samsung Air Conditioner Error Code E407

E407 indicates a PWM discharge temperature sensor OPEN or SHORT error in the outdoor unit. The control board has detected a sensor signal voltage outside the valid operating range, either above 4.95V (indicating an open circuit, associated with readings below -30°C) or below 0.5V (indicating a short circuit, associated with readings above 151°C). This fault is only triggered when the outdoor temperature is above -10°C.

No, you should not attempt to bypass or continue running the system with an active E407 error. The discharge temperature sensor protects the compressor from overheating. Without accurate discharge temperature data, the system cannot prevent compressor damage, which could lead to a much more expensive failure.

A power reset may temporarily clear the error code, but it will return if the underlying sensor or wiring fault has not been corrected. The control board re-evaluates the sensor circuit each time the system runs, so the E407 will reappear as soon as the fault condition is detected again. A reset alone is not a repair.

Some basic checks are within reach for a knowledgeable DIYer. You can inspect the sensor connector on the outdoor unit for looseness, corrosion, or visible wiring damage. However, measuring sensor resistance accurately and replacing the thermistor or control board requires access to the outdoor unit's electrical components, so a qualified technician is recommended if the connector inspection does not reveal an obvious issue.

Repair costs vary depending on the root cause. If the issue is a loose connector or minor wiring repair, labor costs may be the primary expense, typically in the range of $75 to $150. Replacing the discharge temperature sensor itself usually costs $50 to $150 for parts plus labor. If the outdoor control board has failed, parts and labor combined can range from $300 to $600 or more.