Samsung Air Conditioner Error Code E424

E424 indicates a high pressure sensor OPEN or SHORT circuit fault detected when the compressor is preparing to run. A SHORT is flagged when the sensor output voltage drops below 0.4V, and an OPEN is flagged when it rises above 4.2V. The compressor is prevented from operating until the fault is resolved. This is a protective measure to prevent damage from operating with an unreliable pressure reading.

No. The E424 error prevents the compressor from operating because the high pressure sensor is not providing a valid reading. Attempting to bypass or ignore this fault removes an important safety protection, as the system would have no reliable way to detect dangerously high refrigerant pressures. Do not operate the unit until the sensor circuit has been repaired and verified.

Repair costs depend on what is causing the fault. If only a connector or wiring repair is needed, costs are generally lower, typically in the range of $75 to $200 including labor. Replacing the high pressure sensor itself can range from $150 to $400 depending on the unit and labor rates in your area. Control board replacement, if required, is usually the most expensive option and can range from $300 to $700 or more.

Some basic checks are within reach for a knowledgeable DIYer, such as inspecting the sensor wiring harness for visible damage and ensuring the connector is fully seated. However, measuring sensor output voltage, testing the sensor itself, and handling refrigerant-side components typically require professional tools and certifications. It is recommended to have a qualified HVAC technician diagnose and repair this fault.

A power reset may temporarily clear the fault display, but if the underlying sensor or wiring problem still exists, the error will return when the compressor attempts to start again. The fault is detected at the point of compressor activation, so it will reappear unless the root cause is corrected. A reset alone is not a repair.