In this guide, you will find instructions on how to change the oxygen (O2) sensor on an Audi.

This guide will show you how to change the upstream oxygen sensor for the catalytic converter. That would be Bank 1 Sensor 1 or Bank 2 Sensor 1. 

In addition, to change the downstream oxygen sensor for the catalytic converter you will need to jack up the car and/or use ramps. In addition, you will have to remove the splash shield from underneath the car.

Symptoms

• Check Engine Light is ON
• A decrease in fuel economy
• Engine Hesitation or misfiring
• Rough Idling

What you will need

• Audi Oxygen Sensor
• Oxygen Sensor Tool
• Ratchet Wrench
• Penetrating Oil
• Jack and Jack Stands 
  • For downstream sensors. Bank 1 Sensor 2 and Bank 2 Sensor 2 Only. 

Procedure

1. Park your Audi, set the parking brakes, and open the hood. Allow the engine to cool down or you will risk getting burned. Open the hood.
2. Disconnect the negative battery terminal. 

3. Locate the oxygen sensor on your Audi. Above, you'll see the upstream oxygen sensor on an Audi Q5.Location of O2 sensor on Audi A4.

   
4. Disconnect the O2 sensor. Press the connector and pull it away to unplug the connector. 

5. Remove the sensor and place the oxygen sensor socket on the sensor and break it loose. Remove the old Audi oxygen sensor.

6. You may need to spray penetrating oil and allow it to sit for at least 10 minutes. Especially on high mileage Audi cars where the oxygen sensor is stuck.
7. Install the new O2 sensor. Tighten your new Audi oxygen sensor to the new sensor hand tight then turn an extra 1/2-3/4 turn. 
8. Connect the oxygen sensor wire harness by plugging it in. If you are using a universal oxygen sensor you will need to use the diagram that came with the sensor to find out which wires to splice. 

The typical cost to change the Audi oxygen sensor yourself is around $100. 

This guide will help owners of Audi models such as the A1, A3, A4, A5, A6, A7, Q3, Q5, Q7, and TT.