Bank 1/Sensor 1

Disconnect the battery (-) terminal.
Disconnect the heated oxygen sensor connector (A), and then remove the clip (B).

Courtesy of HYUNDAI MOTOR AMERICA
Remove the heated oxygen sensor (A).
Tightening Torque:

39.2 - 49.0 N.m (4.0 - 5.0 kgf.m, 28.9 - 36.1 lb-ft)

Courtesy of HYUNDAI MOTOR AMERICA