Samsung Air Conditioner Error Code E165

E165 means the system detected no change in the evaporator outlet temperature during its piping check routine. The piping check is designed to confirm that refrigerant is flowing properly through the indoor unit. When the sensor reading does not change as expected, the unit flags E165 and halts operation. The most common starting points for diagnosis are the indoor unit address configuration and the EEV connection to the PCB.

E165 is a diagnostic fault rather than an immediate safety hazard. The system stops normal operation and reports the error to prevent running in an unverified state, which protects the compressor and refrigerant circuit from potential damage. You can leave the unit powered off until a technician evaluates it without risk of injury.

A power reset may temporarily clear the error code and allow the unit to restart, but if the underlying cause is still present, the piping check will fail again and E165 will return. Resetting without fixing the root cause is not a lasting solution. Address the address configuration, EEV connection, thermistor, or PCB issue first to prevent the fault from recurring.

Some steps, such as verifying the indoor unit address setting and visually inspecting the EEV wiring harness for a loose connection, can be performed by a knowledgeable DIYer comfortable working with electronics. However, testing EEV coil resistance, checking thermistor values, and replacing PCB components typically require proper tools and familiarity with refrigerant systems. If the wiring and address checks do not resolve the error, a certified technician should complete the diagnosis.

Repair costs vary depending on the root cause. If only an address setting or a connector needs correction, costs are primarily for the service call and labor, typically in the range of $75 to $150. Replacing an EEV coil or thermistor adds parts costs, generally bringing the total to $150 to $400. A full PCB replacement is the most expensive scenario, often ranging from $300 to $600 or more depending on the model and labor rates in your area.