How to Replace an Oxygen Sensor

Oxygen sensors are one of the most important components on a modern vehicle’s engine management system. They are responsible for monitoring the air fuel mixture of the engine, and their readings affect important engine functions such as timing and air fuel mixture.

Over time, with normal use, oxygen sensors can begin to function with a delayed response, and they will eventually fail. Typical symptoms of a failed oxygen sensor are decreased engine performance, decreased fuel efficiency, rough idle, and in certain cases, even misfires. Usually a failed oxygen sensor will also set off a check engine light, specifying which sensor on what bank has failed.

In most cases, replacing an oxygen sensor is a relatively straightforward procedure that usually only requires a few tools. In this step by step guide, we will go over what removing and replacing an oxygen sensor typically entails.

Part 1 of 1: Replacing an oxygen sensor

Materials Needed

scanning tool

Step 1: Identify the faulty sensor. Before beginning, connect the OBD II scan tool to the vehicle and read the codes to determine which specific oxygen sensor has failed and needs to be replaced.

Depending on the engine design, vehicles can have multiple oxygen sensors, sometimes on both sides of the engine. Reading the trouble codes will tell you exactly which sensor is in need of replacing — either the upstream (top) or downstream (bottom) sensor — and on what bank (side) of the engine.

vehicle raised on jack stands

Step 2: Raise the vehicle. Once the faulty sensor has been identified, raise the vehicle and secure it on jack stands. Be sure to raise the vehicle on the side which you will allow you to access the oxygen sensor that needs to be replaced.

person disconnecting the oxygen sensor

Step 3: Disconnect the oxygen sensor connector. With the vehicle raised, locate the faulty oxygen sensor and disconnect the wiring harness connector.

person using tools to remove the oxygen sensor

Step 4: Remove the oxygen sensor. Using the oxygen sensor socket or the appropriate size open end wrench, loosen and remove the oxygen sensor.

side by side comparison of the oxygen sensor

Step 5: Compare the faulty oxygen sensor with the replacement sensor. Compare your old oxygen sensor with your new replacement to ensure the correct fitment.

new oxygen sensor installed

Step 6: Install the new oxygen sensor. Once fitment has been verified, install your new oxygen sensor, and connect the harness.

person using a scan tool to erase the trouble codes

Step 7: Clear the codes. Once the new sensor has been installed, it is time to clear the codes. Connect the OBD II scan tool to the vehicle and clear the codes.

person inserting and turning key in the ignition

Step 8: Start the vehicle. Once the codes have been cleared, remove and reinsert the key, and then start the vehicle. The check engine light should now be gone, and the symptoms you were experiencing should be alleviated.

In most vehicles, replacing an oxygen sensor is a simple procedure that requires only a few tools. However, if this is not a task you are comfortable doing on your own, this is something that any professional technician, such as one from YourMechanic, can take care of quickly and easily.

Next Step

Schedule Oxygen Sensor Replacement

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Recent Oxygen Sensor Replacement reviews

Excellent Rating


Rating Summary


23 years of experience
25 reviews
23 years of experience
Lexus ES350 - Oxygen Sensor Replacement (Front/Upper/Upstream) - Marietta, Georgia
James was great!! He answered all my questions, was patient and professional. I don’t want to have to use a mechanic any time soon but if I have to I would request James.
Chevrolet Malibu - Oxygen Sensor Replacement (Front/Upper/Upstream) - Austell, Georgia
Very nice, very knowledgeable, and got the job a lot quicker than I expected. He even recommended what should be done next. Extremely helpful. Would recommend.


14 years of experience
277 reviews
14 years of experience
Toyota Corolla - Oxygen Sensor Replacement (Front/Upper/Upstream) - Chicago, Illinois
Outstanding performance done by Chuy. Not only he did what I asked to do, but also he took care of small details that I would have not caught otherwise! I’d ask Chuy for any other services in the future.
Subaru Outback - Oxygen Sensor Replacement (Front/Upper/Upstream, Rear/Lower/Downstream) - Villa Park, Illinois
Church had to work extra hard to make sure that the repairs were properly done. The work was completed to my satisfaction. Thank you.


20 years of experience
653 reviews
20 years of experience
Hyundai Santa Fe - Oxygen Sensor Replacement (Rear/Lower/Downstream) - Los Angeles, California
Kenneth came early and did the work in record time. He also made recommendations for additional things ne noticed needed to be done.
Chevrolet Suburban 2500 - Oxygen Sensor Replacement (Front/Upper/Upstream, Rear/Lower/Downstream) - Pico Rivera, California
Great communication with updates on vehicle status and recommended services. Would recommend and book again for maintenance needs.


17 years of experience
269 reviews
17 years of experience
Chevrolet Cruze - Oxygen Sensor Replacement (Front/Upper/Upstream, Rear/Lower/Downstream) - San Antonio, Texas
There is nothing negative to say about the services rendered. Best experience ever getting a vehicle fixed. I will be a repeat customer.

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