Disconnect the cable from the negative battery terminal. For four-cylinder models, the two knock sensors are located on the front side of the block, behind the intake manifold. Remove the intake manifold, then disconnect the electrical connector from the knock sensor. Remove the knock sensor bolt and take out the knock sensor, ensuring the right-hand sensor is installed with the wire end pointing towards the 6 o'clock position and the left side sensor towards the 3 o'clock position. Installation is the reverse of removal, and the knock sensor bolt should be tightened to the specified torque. For V6 models with a 3.0L engine, a single knock sensor is located on the left rear side of the engine block. Raise the rear of the vehicle and support it securely on jackstands, then loosen the knock sensor heat shield and position it aside. Disconnect the knock sensor electrical connector, remove the mounting bolt, and take out the sensor. Installation is the reverse of removal, with the knock sensor bolt tightened to the specified torque. For 3.SL engines, the knock sensors are located in the valley between the cylinder heads, under the coolant pipe, sharing the same wiring harness and needing to be replaced as a pair. Remove the upper and lower intake manifold, then remove the thermostat housing and coolant tube. Disconnect the knock sensor electrical connector, remove the knock sensor bolts, and take out the knock sensors. Installation is the reverse of removal, and the knock sensor bolts should be tightened to the specified torque.