How to Replace an O2 Sensor in a BMW


Instructions
1. Find the oxygen sensor on the pre-catalytic converter. This is located near the front-right wheel well.
2. Remove the large air intake pipe connected to the air box and rear turbo. You will also need to remove the two smaller air pipes connected to the air box and blow off valves. Soak the old O2 sensor with penetrating lubricant (WD-40 or equivalent) to make removal easier.
3. Use the 7/8-inch wrench to remove the old O2 sensor. Locate the engine lift loop near the firewall to find the stock sensor wire. Splice this wire and connect it with the wires of the new O2 sensor using crimp connectors.
4. Apply a small amount of anti-seize paste to the threads of the new O2 sensor. Be careful not to get any of the paste on the rest of the sensor or it will ruin it. This will make removal of the sensor easier for next time.
5. Screw in the new O2 sensor by hand as tight as you can get it. Use the wrench to fully tighten it. Snap in the connecting wires back into the wire holders. Reconnect all the air pipes again.