How to Replace an O2 Sensor on a 2001 Audi A6 4.2


1. Jack up the front of the vehicle using a floor jack under the front jack point behind the radiator.
2. Place a jack stand under each of the front pinch welds under the front doors and lower the A6 onto the stands.
3. Locate the O2 sensors on the exhaust. The O2 sensors look like small plugs secured to the exhaust with wires attached to them. There will be one before the catalytic converter and one after the converter on the exhaust pipe.
4. Disconnect the electrical connectors running to the O2 sensors.
5. Unscrew the O2 sensors from the exhaust using an O2 sensor socket, turning in a counterclockwise direction.
6. Thread and tighten the new O2 sensors.
7. Reconnect the electrical connectors to the O2 sensors.
8. Lower the A6 to the ground using the floor jack.