Samsung Air Conditioner Error Code E242

E242 indicates an open or short circuit fault in the equal oil temperature sensor circuit in the outdoor unit. This sensor monitors compressor oil temperature to protect the system during operation. The error means the control board is receiving a signal that falls outside the expected range, either no signal at all or an abnormally low resistance reading. The system flags this fault to prevent potential compressor damage from running without accurate oil temperature data.

It is not recommended to continue operating the unit while E242 is active. The oil temperature sensor is a protective component, and running the system without accurate oil temperature monitoring could result in compressor overheating or damage. You should address the fault before resuming normal operation to avoid more costly repairs.

A power reset may temporarily clear the error display, but if the underlying fault in the sensor circuit is still present, E242 will return once the system runs a diagnostic cycle again. Resetting without addressing the cause does not fix the problem. A proper repair of the sensor, wiring, or connector is required to permanently clear the code.

Some basic checks are accessible to a knowledgeable DIYer, such as verifying the sensor connector is securely seated on the outdoor PCB. However, testing sensor resistance, inspecting wiring harnesses, and replacing components inside the outdoor unit typically require familiarity with HVAC electrical systems and refrigerant safety. If you are not comfortable working inside the outdoor unit, a qualified technician should perform the diagnosis and repair.

Repair costs vary depending on the root cause. If only the connector needs to be reseated, there may be no parts cost, just a diagnostic service fee. Replacing the oil temperature sensor typically costs between $50 and $150 for the part, plus labor. If the outdoor PCB needs replacement, total costs can range from $300 to $700 or more depending on the model and technician rates.