There is one knock sensor on 2005 and earlier models and two on 2006 and later models, located in the valley between the cylinder heads. Begin by disconnecting the cable from the negative battery terminal. Next, remove the intake manifold and disconnect the electrical connector(s) of the knock sensor(s). For 2005 and earlier models, unscrew the knock sensor; for 2006 and later models, unscrew the mounting bolt and remove the sensor. Installation is the reverse of removal, ensuring to tighten the knock sensor or mounting bolt to the specified torque.