Samsung Air Conditioner Error Code E266

E266 means the top temperature sensor on compressor 1 has become detached or lost contact with the compressor body. This thermistor monitors the compressor temperature to protect it from overheating. The control board cannot receive a valid reading from the sensor and flags the fault to prevent potential compressor damage.

Running the system while E266 is active is not recommended. The top compressor sensor provides critical temperature protection, and without an accurate reading the control board cannot properly safeguard the compressor from overheating. Continued operation could result in compressor damage, which is a significantly more expensive repair.

If the sensor only needs to be reattached and no parts are required, you may only pay for a service call, typically in the range of $75 to $150 depending on your area. If the thermistor itself has failed and needs replacement, parts and labor combined generally run between $100 and $250. Costs can be higher if the fault caused compressor damage due to delayed repair.

If the sensor has simply slipped out of its retaining clip, a knowledgeable DIYer can reseat it and verify the wiring connections without special tools. However, if the fault requires working inside the outdoor unit near refrigerant lines or electrical components, a qualified technician should perform the repair. Replacing a failed thermistor is a straightforward parts swap but does require accessing the compressor area of the outdoor unit.

A reset will clear the displayed fault temporarily, but E266 will return if the underlying sensor issue has not been corrected. The sensor must be physically reattached and confirmed secure, or replaced if defective, before the fault will stay cleared during normal operation.