DTC P0141-00: O2 Sensor Heater Circuit (Bank 1/Sensor 2): General Description
WARNING: This page is about a different car, the 2018 Hyundai Accent. However, it is still accessible from the selected car via links, so may be relevant.
HO2S (S2) is in the rear side of Catalytic Converter to check the proper operation of catalyst. Oxygen density after the catalytic converter has to be within specific range (around 0.5V when there is no acceclation and deceleration.) If the oxygen density changes in accordance with HO2S (S2), it means the poor performance of catalytic converter.