How to Replace a Mercedes Oxygen Sensor

1. Jack the vehicle off the ground using the Mercedes front jack point. Place the jack stands under the frame of the vehicle (on either side) and lower the Mercedes onto the jack stands.
2. Locate the O2 sensor underneath the Mercedes. It will be located near the catalytic converter, sticking out of the exhaust piping. Unplug the electrical connectors from the O2 bung housing.
3. Loosen and remove the O2 sensor using the O2 sensor removal tool. Place the tool over the end of the O2 sensor and turn it counterclockwise.
4. Apply a small amount of anti-seize compound to the threads of the O2 sensor. This will help to prevent seizing of the threads the next time you have to change the sensor, making it easier to remove.
5. Install the new O2 sensor by reversing Step's 3 procedure.