How to Change O2 Sensors

Also known as air-fuel ratio sensors and oxygen sensors, the O2 sensor in your vehicle measures your exhaust’s oxygen levels and alerts the computer when rich or lean fuel mixtures are detected to allow the fuel mixture to be altered appropriately. The oxygen sensors in your car are integral to the performance and gas mileage, so it is important to inspect this item if you notice signs of failure. Bad O2 sensor symptoms include stalling, a rough idle, decreased fuel efficiency and engine performance, a Check Engine light that turns on, or increased exhaust and emissions. O’Reilly Auto Parts stocks the right tools and parts, including O2 sensor sockets, and replacement upstream and downstream oxygen sensors to help you repair your car, truck, or SUV in no time.

Tools & Materials

safety glasses Safety Glasses
Protective Gloves Nitrile Gloves
O2 sensor O2 Sensor
O2 sensor socket O2 Sensor Socket
floor Jack Jack
jack stands Jack Stands
o2 sensor wrench power torque O2 Wrench
anti-seize anti seize lubricant versachem Anti-Seize Lubricant

Instructions

For this job we will start with the car raised. Check out our video on how to safely jack up your vehicle. If you’re not completely comfortable doing the job yourself, we’d be happy to recommend a professional technician in your area.
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pointing out o2 sensor

Step 1: Determine the Sensor to Be Replaced

The first thing you’ll need to do is determine which sensor needs to be replaced. Each side of the vehicle has upstream and downstream O2 sensors. In our example we’ll be replacing the downstream sensor on the passenger side of the vehicle.

Do It Right: Stop by your local O’Reilly Auto Parts Store, and we’ll scan your codes for free to help you determine which sensor you need. Find A Store.

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Hand locating and removing old O2 sensor

Step 2: Locate and Remove the Old O2 Sensor

With the car raised, we’ll locate the sensor that needs replacing, which screws directly into the exhaust system.
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disconnect the electrical wire by pushing the tab

Follow the electrical wire away from the sensor and disconnect it by pushing the tab down and pulling the two halves apart.
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unscrewing the sensor socket by hand

Once it’s disconnected, use your socket to loosen the sensor, and then finish unscrewing it by hand.
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applying anti-seize lubricant to new o2 sensor

Step 3: Install the New O2 Sensor

Next, apply anti-seize to the threads of your new sensor, being careful not to get any on the sensor itself. Some sensors will come with a packet of anti-seize, and some will already be treated.
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thread the new sensor in place with the wire

Thread the new sensor into place with your fingers, making sure it threads properly and smoothly.
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tighten the sensor to specs

Finally, tighten it to manufacturer’s specifications with your socket.
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reconnect electrical wire

Reconnect the electrical wire.
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If you have more than one sensor that requires replacement, the steps will be the same for each one.
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Additional Resources

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How to Clean Your Windshield
how to replace wiper blades

How to Install Wiper Blades
how to replace blower motor

How to Replace Blower Motor

The automotive repair work depicted in this series is performed under the direction of the manufacturer of the product featured. Prior to undertaking any of the demonstrated repairs on your vehicle, we suggest you consult with a certified mechanic or another professional who can adequately advise you of the proper repair or remedy required. O’Reilly Automotive Stores, Inc. and its affiliates (“O’Reilly”) disclaims any responsibility for injury or damage resulting from a viewer’s attempt to recreate the repairs shown in this series.