When servicing an oxygen sensor, exercise caution,the oxygen sensor has a permanently attached pigtail and electrical connector that should not be removed, and contaminants like grease and dirt must be kept away from the electrical connector and the sensor's louvered end. Avoid using cleaning solvents on the sensor, prevent rough handling or dropping, and ensure correct positioning of the silicone boot to prevent melting and ensure proper sensor operation. For upstream oxygen sensors, locate the electrical connector and disconnect it, detaching the sensor wiring harness from clips if necessary. Unscrew the sensor using an oxygen sensor socket, and if reusing the old sensor, apply anti-seize compound to the threads. Installation is the reverse of removal. For downstream oxygen sensors, raise the vehicle securely on jackstands, disconnect the wiring harness from the sensor's pigtail, and unscrew the sensor with an oxygen sensor socket. Again, if reusing the old sensor, apply anti-seize compound to the threads before securing the sensor tightly during installation.