Samsung Air Conditioner Error Code G4

The G4 code indicates that the oil temperature sensor has broken away or disconnected from the compressor, and this was detected at least once during the first 30 minutes of compressor operation. The sensor monitors compressor oil temperature to protect the unit from thermal damage. Without a secure sensor connection, the system cannot safely verify compressor conditions and will flag this fault.

Running the unit with an active G4 fault is not recommended. The oil temperature sensor exists specifically to protect the compressor from overheating, and without a reliable sensor reading, the control board cannot detect unsafe temperature conditions. Continued operation under this fault risks undetected thermal stress and potential compressor damage.

If the sensor only needs to be reseated and no parts are required, repair costs may be limited to a service call fee, typically in the range of $75 to $150 depending on your area. If the sensor, mounting hardware, or wiring harness needs replacement, total repair costs could range from $150 to $400 or more, depending on parts availability and labor rates. Getting a diagnosis before authorizing repairs is the best way to understand the full scope of cost.

The first step is to check whether the oil temperature sensor has physically separated from the compressor and to reseat it if so. This is a mechanical inspection that a knowledgeable DIYer may be able to perform if they can safely access the outdoor unit and compressor. However, if the wiring is damaged or the sensor itself has failed, a technician with proper tools and replacement parts will be needed to complete the repair.

A simple power reset is unlikely to permanently clear the G4 code because the fault is caused by a physical sensor disconnection, not a software glitch. The code will likely return once the compressor starts and the control board again detects a missing or invalid sensor signal. The underlying sensor connection issue must be resolved before the error will stay cleared.