How to Check and Replace an Oxygen Sensor

How to Check and Replace an Oxygen Sensor: Do It On Your Own

You might not realize it, but an oxygen sensor is one of the most important parts of your car. Without being too technical, the main function of the oxygen sensor is to improve the efficiency of the engine operation. It detects the oxygen content in the exhaust stream. It gauges the fuel mixture, letting you know if it is burning rich or lean.

It is paramount for any driver to maintain the best condition of the oxygen sensor. In some instances, it might not be broken, but a replacement is still necessary. In fact, according to experts, it needs to be replaced after every 100,000 miles. This can be a bit costly, but it is one thing that should not be ignored for the optimal performance of your car.

Now, if you are wondering how to check and replace an oxygen sensor, this post is for you. I will let you know how to inspect the sensor to be sure that it is the problem. More importantly, the discussions below will also cover how you can replace the sensor. It might seem difficult at first, but it is actually a straightforward task.

What You Will Need to Follow This Tutorial

To successfully complete this task, be sure that you have the following materials:

  • Multimeter
  • Oxygen sensor replacement
  • Oxygen sensor socket
  • Gloves
  • Wrench

Step-by-Step Guide on How to Check and Replace an Oxygen Sensor

Before anything else, you have to make sure that there is a problem with the oxygen sensor.

Check and Replace an Oxygen Sensor


  • The most obvious indication of the problem is the blinking of the Check Engine light.
  • By now, you already know that there is a problem with the engine, but you are still not sure that it is the oxygen sensor. This is the time when you will need to use a multimeter to diagnose the problem.
  • Before working, make sure that the engine is cool. It is extremely hot and you will burn yourself if you rush to work.
  • Look for Bank 2, Sensor 1. Test the sensor. This will provide you with an assurance that the actual source of the problem is the sensor.
  • Press the tab and pull out. By this time, you should see four wires – two black, one blue, and one white. Use a multimeter. Connect the multimeter to the prongs connecting to the black wires. If there is no resistance or reading, this is an indication that you have a problem.
  • Now that you are sure that the oxygen sensor is the issue, it is time to have it replaced with a new one.

You are ready to replace your faulty oxygen sensor. To be sure that you are doing it the right way, these are the things that you should do:

  • Use an oxygen sensor socket. You do not have to buy a new one. You can rent it from a local mechanic. This is going to make the task a lot easier and quicker to accomplish. The main function is to strip the old sensor and install a new one easily.
  • Slide the socket into the wire. Once it is in place, use a wrench to remove the old sensor. Screw it all the way until it is completely removed. To be sure, wear thick gloves as the surface can still be hot.
  • Install the new oxygen sensor. Before you proceed, compare the new one with the old one and make sure that they are the same. You can also remove the old one first, bring it to a car parts store, and ask them to give you the same one. This way, there is a lesser likelihood that you will end up committing a mistake.
  • Thread the new oxygen sensor in its place. Use the socket to do this. Connect the clip on the other end.
  • It is important to make sure that the sensor is not too loose, as the gases can escape. On the other hand, if you tighten it too much, the sensor can end up being damaged. Use a torque wrench to be sure.
  • Start the engine and see if the Check Engine light is still on. If it does not blink anymore, this means that the problem has been successfully fixed.

For a visual guide of the steps that have been mentioned above, this short video will help:

Pro Tips

To guarantee the best outcomes, here are some of the tips that you have to keep in mind:

  • A quick visual inspection will already give you an idea that an oxygen sensor is damaged. Usually, the color should be light tan. If it is light gray, black, or white, this can be a sign that there is a need for a replacement. Nonetheless, you should still proceed with the testing to be sure.
  • It is important that you protect your hands by wearing gloves, as noted in the steps I have mentioned above. You should also be careful with the probes. See to it that their tips won’t end up touching the exhaust pipe or the exhaust manifold because its extreme heat can damage the probes.
  • The oxygen sensor can be extremely fragile. For this reason, you need to handle it with extreme caution. The tip should not get in contact with anything as it can end up being contaminated. It is made from a special type of ceramic, so you have to be extra cautious.
  • Always consult with the manual from the manufacturer. The appearance of oxygen sensors may differ depending on the car that you have, so that means there can be different approaches to how things should be done.
  • Do not use oils and sprays to clean the oxygen sensors. They contain contaminants that will have a negative effect on the performance and function of the sensors.
  • Generally speaking, oxygen sensors do not need care and maintenance. Once they become faulty, they can no longer be saved. Instead, the best thing to do is to have them replaced.


Knowing how to check and replace an oxygen sensor is vital for every car enthusiast, which can also help you save a lot of money in the long run. You do not need to rely on the services of a local mechanic and pay them for the job. You can do it on your own, but you have to be careful, especially in terms of determining that this is actually the problem.

Have you tried checking and replacing an oxygen sensor before? Is there anything else that you would like to share? Do not hesitate to leave a comment below.