How to change an oxygen sensor on Cars

by Contributing Writer; Updated June 12, 2017

If the check engine light on the dash of your Jeep car is on, stop into an auto parts store and ask them to scan your Jeep car for codes. Nearly all major auto parts store offer this service for free. Failure of the oxygen sensor is a common problem, but the part can be changed at home, saving you a major repair bill. The oxygen sensors are in the exhaust pipe between the engine and the catalytic converter on the Jeep car. You will need a special socket to remove the oxygen sensor, available at most auto parts stores and tool supply stores.

Under The Hood:

 How to change an oxygen sensor on Jeep Grand Cherokee

First you must locate the bad oxygen sensor. You can have your car diagnosed at Auto Zone for free which will specify which sensor out of four sensors. The 1993-2004 Jeep Grand Cherokee 4.0L engines have four oxygen sensors. Two located upstream and two located downstream. See attached diagram. 2 upstream (referred to as 1/1 and 2/1) and 2 downstream (referred to as 1/2 and 2/2). With this emission package, the rear/upper upstream sensor (2/1) is located in the exhaust downpipe just before the rear mini-catalytic convertor. The front/upper upstream sensor (1/1) is located in the exhaust downpipe just before the front mini-catalytic convertor. The rear/lower downstream sensor (2/2) is located in the exhaust downpipe just after the rear mini-catalytic convertor, and before the main catalytic convertor. The front/lower downstream sensor (1/2) is located in the exhaust downpipe just after the front mini-catalytic convertor, and before the main catalytic convertor.

Second you must purchase your oxygen sensor either from a local automotive parts store or online. I recommend BOSCH oxygen sensors. All four oxygen sensors located in the Jeep Grand Cherokee are different prices and sizes. While you are purchasing your oxygen sensor, ask the store clerk or look online for an oxygen sensor socket. It has a split down the middle for the cable to fit.

Third, use the picture above for specific location on the oxygen sensor you need to replace. Use the socket to remove the bad oxygen sensor and replace it with the new one.

Items you will need

  • Oxygen sensor(BOSCH)

  • Split oxygen sensor socket.

  • Socket wrench

 How to Replace the Oxygen Sensor in a Buick Rendezvous

Removing the Oxygen Sensor

Drive your Rendezvous for 20 minutes on the highway, to bring the engine up to operating temperature. Drive home, and park on level ground. Raising the exhaust system temperature will make it easier to unthread the oxygen sensor.

Open the hood, and locate the primary oxygen sensor, mounted on the exhaust manifold, near the front exhaust pipe that connects to the manifold. Locate the secondary oxygen sensor, at the rear of the catalytic converter. The converter is the rectangular metal box, between the front and rear exhaust pipes.

Remove the exhaust manifold heat shield with a ratchet, short ratchet extension and socket, if you have a 3.5-liter engine model.

Raise the front of your vehicle with a floor jack, and support it on two safety stands, if you need better access to the O2 sensor on your particular Buick model. Apply the parking brakes, and install a chock against each of the rear wheels, to keep the vehicle from rolling.

Put on your goggles; get under the vehicle, and unplug the oxygen sensor electrical connector. Detach the sensor electrical connector, by hand, from the clip that secures the connector away from the exhaust pipe, if you have the 3.5-liter engine model.

Unfasten, and remove, the sensor, with an oxygen sensor socket and a ratchet.

Installing the New Oxygen Sensor

Coat the threads of the new sensor with anti-seize compounds, but do not get any compound on the tip of the sensor.

Thread the new sensor, finger tight, and tighten the sensor to 30 ft-lbs. (41 Nm), with a torque wrench and the oxygen sensor socket.

Plug in the sensor electrical connector.

Attach the sensor electrical connector, by hand, to the clip, to secure it away from the exhaust pipe, if you have the 3.5-liter engine model.

Lower your Rendezvous off the safety stands, and remove the chocks from the rear wheels.

Items you will need

  • Ratchet

  • Short ratchet extension, if necessary

  • Socket, if necessary

  • Floor jack, if necessary

  • 2 safety stands, if necessary

  • 2 chocks, if necessary

  • Goggles

  • Oxygen sensor socket

  • Anti-seize compound

  • Torque wrench

 How to Replace an Oxygen Sensor in a Wrangler

Lift the Jeep with a jack and support it on all four corners with a set of jack stands. The oxygen or O2 sensors are in the exhaust under the middle of the Jeep, so you will have to lift the entire Jeep to access them effectively.

Locate the two O2 sensors in the exhaust system. The first one is near the center of the transmission, and the second is between the resonator and the catalytic converter. Unplug the wiring harness connectors from both sensors by lifting the locking tab with a small flat screwdriver and pulling them from the harness.

Remove the O2 sensors, one at a time, using a oxygen sensor socket and a ratchet. Turn the sensor counter-clockwise to remove it from the exhaust. Discard the old sensor.

Install the two new sensors into the threaded sections of the exhaust where you removed the old ones from. The two sensors used by Jeep are identical, so either one is fine in each hole.

Tighten the sensors with an oxygen sensor socket and a torque wrench to 22 foot-pounds. Do not use thread locker, anti-seize or any other compound on the threads of the sensor.

Insert the wiring harness connectors on both sensors into the plugs on the wiring harness. Verify that they lock into the connector by checking the tab to see that it is engaged.

Remove the jack stands and lower the Jeep to the ground. Test run the engine and check your CEL or check engine light to ensure it has gone off.

Items you will need

  • Jack

  • Jack stands

  • Small flat screwdriver

  • Oxygen sensor socket

  • Ratchet

 How to Replace an Oxygen Sensor in a Dodge Ram

Remove the Oxygen Sensor

Turn on the engine and let it idle for about three minutes.

Raise the front of your Dodge Ram using a floor jack and safely support it with two jack stands.

Locate the sensor(s) by following the front and back exhaust pipes connected to the catalytic converter. You will find a sensor on each side of the converter. If your particular model is equipped with double catalytic converter, there should be another pair of sensors attached to the second unit. These sensors have a cylindrical body about the size of a spark plug, and will have a tail wire and an electrical connector.

Unplug the oxygen sensor's electrical connector.

Unscrew the oxygen sensor using a box-end wrench or ratchet, ratchet extension and oxygen sensor socket (see Resources). Remove the sensor from the vehicle.

Install a New Oxygen Sensor

Apply a light coat of anti-seize compound to the threads of the new oxygen sensor. This will make it easy to remove the next time and prevent the threads from being damage. Make sure to keep your fingers, dirt and other contaminants off the tip of the sensor, which may interfere with its proper operation.

Hand-start the sensor in place to prevent thread damage.

Tighten the sensor using the box-end wrench or ratchet, ratchet extension and oxygen sensor socket, but do not over-tighten.

Plug the oxygen sensor's electrical connector.

Replace the next sensor, if necessary, by following Step 3 from the previous section through Step 4 of this section.

Items you will need

  • Floor jack and jack stands

  • Box-end wrench

  • Ratchet, ratchet extension and socket

  • Anti-seize compound

 How to Change an Oxygen Sensor in a Mitsubishi Lancer

Raise the front end of your Lancer off the ground with a jack and support it with jack stands so you can safety work under it. Be sure you are on flat ground so the car stays still while you work.

Locate the catalytic converter under your car. It is in front of the muffler near the front of the exhaust system. The O2 sensor will be right in front of it or right behind it, depending on which engine you have in your car.

Disconnect the wiring harness connector for the O2 sensor by depressing the locking tab and sliding the connectors apart. You can leave the connector coming from the wiring harness hanging; you will connect the new sensor to it shortly.

Remove the O2 sensor from the exhaust pipe using an O2 sensor socket and a ratchet. Turn the sensor counter-clockwise until the sensor is free.

Insert the new sensor into the pipe and turn it clockwise to tighten it with the socket and ratchet. Connect the new O2 sensor to the wiring harness by plugging the pig tail into the wiring harness connector. Make sure it locks into the connector.

Lift the front of the car with a jack and remove the jack stands. Slowly lower the car to the ground, then start it to ensure it is running properly.

Items you will need

  • Jack

  • Jack stands

  • Ratchet

  • Oxygen sensor socket

 How to Change the Oxygen Sensor on a VW Beetle

Start your car and drive around till the vehicle reaches the normal operating temperature. Park on a level surface and set the parking brake. Chock the rear wheels.

Jack the front of the vehicle and support the front end with jack stands. After the vehicle's weight is being supported by the jack stands, let the jack support the center of the front end. This adds stability and another layer of safety.

Locate the sensor on the exhaust pipe. The sensor is mounted on top of the exhaust pipe, just forward of the catalytic converter. Wear gloves as the exhaust system will be hot. See Photograph Step 3.

Follow the sensor wiring aft to locate the junction box. Using the crescent wrench, remove the two nuts and remove the junction box cover. Pop the sensor's connector end out of the junction box and disconnect from the car's harness. The sensor harness is secured by clips. Remove the harness from the clips and remove the heat shield blanket that snaps in place over the harness. Take the 7/8-inch wrench and remove the sensor. See Photograph Step 4.

Place anti seize on the new sensor's threads. Install the new sensor and tighten securely. Reinstall the harness and connector in the reverse order of the above steps.

Items you will need

  • Oxygen sensor

  • 7/8-inch open end wrench

  • Small crescent wrench

  • Anti seize compound

  • Jack

  • Jack stands

  • Wheel chocks

  • Gloves

 How to Replace an Oxygen Sensor in a Sable

Locate the oxygen (O2) sensor, screwed into the driver's side exhaust manifold. The sensor has a green wire coming out of it and looks similar to a spark plug. Use the replacement O2 sensor for a visual aid.

Trace the green wire from the sensor to the wiring harness the wire connects to. Unplug the wire from the harness.

Remove the sensor from the exhaust manifold, using an open-ended wrench. The sensor is removed by turning counterclockwise.

Thread the new sensor into the hole in the exhaust manifold with your fingers, and tighten it with the open-ended wrench.

Plug the green wire on the new O2 sensor into the wiring harness. Complete Step 1 through Step 5 with the passenger side's exhaust manifold sensor.

Locate the driver's side catalytic converter O2 sensor. To do so, follow the exhaust pipe from the exhaust manifold, until you locate the O2 sensor, screwed into a bung on the exhaust pipe.

Trace the green wire from the sensor to the wiring harness the wire connects to. Unplug the wire from the harness.

Remove the sensor from the exhaust pipe bung, using an open-ended wrench. The sensor can be removed by turning it counterclockwise.

Thread the new sensor into the bung in the exhaust pipe with your fingers, and tighten it with the open-ended wrench.

Plug the green wire on the new O2 sensor into the wiring harness. Complete Step 6 through Step 10 with the passenger's side exhaust manifold sensor.

Items you will need

  • Wrench set

 How to Replace the Oxygen Sensor on a Nissan Pathfinder

Raise the front of the truck with a jack and support it with jack stands placed under the frame. Locate the two oxygen sensors in the exhaust system. There is one in the front right exhaust pipe and one in the front left exhaust pipe. They are both slightly down stream from the exhaust manifolds.

Locate the wiring harness connector on the end of the sensor. Disconnect the connector and lay the harness aside.

Remove the oxygen sensor with an oxygen sensor socket and a ratchet, turning the sensor counterclockwise to loosen it. Lift it out of the threaded insert in the exhaust pipe and discard it.

Thread the new sensor into the exhaust pipe fitting and tighten it with the oxygen sensor socket and a ratchet. Plug the electrical connector into the wiring harness connector on the truck.

Move to the second sensor and repeat the process to replace it as well. Support the truck with your jack and remove the jack stands, then lower the truck to the ground.

Items you will need

  • Jack

  • Jack stands

  • Ratchet

  • Oxygen sensor socket

 How to Replace an Oxygen Sensor in a Hyundai Tiburon

Use the floor jack to lift up on the front jack point located just behind the radiator on the Tiburon. The jack point is an extension of the frame of the vehicle and is the only safe jack point on the front of the vehicle.

Place a jack stand under each of the front pinch welds on the driver and passenger sides of the Tiburon.

Lower the Tiburon onto the jack stands.

Climb under the Tiburon and unplug the electrical leads from the O2 sensors. There are two sensors on the Tiburon, one in front of (before) the catalytic converter and one behind (after) the converter.

Place the O2 sensor tool over the O2 sensor and turn it counterclockwise with a socket wrench to loosen and remove it.

Thread and tighten the new O2 sensors using the O2 sensor tool and a socket wrench.

Reconnect the electrical leads to the O2 sensors.

Items you will need

  • Floor jack

  • Jack stands

  • O2 sensor tool

  • Socket wrench

  • Replacement O2 sensors

 How to Replace an Oxygen Sensor in a Nissan Truck

Park the Nissan truck up onto two car ramps and apply the parking brake. Open the hood.

Place a wheel block behind one of the rear tires.

Crawl underneath the truck with all the tools and a pair of safety glasses on. Locate the sensor you need to replace.

Spray the threads of the sensor with a generous amount of penetrating lubricant and allow 5 to 10 minutes to soak in. Repeat this step if necessary.

Locate the wire harness plug of the oxygen sensor and disconnect it.

Use an oxygen sensor socket and a flex-head ratchet for upstream sensor removal or a 22mm box-end wrench for downstream sensor removal. Turn the sensor counterclockwise to remove it from the exhaust port. If using the ratchet and sensor socket, place the wire of the sensor into the slot of the socket. For the 22mm wrench, feed the wire through the wrench before placing the box-end side onto the sensor.

Screw the new sensor into the exhaust port. Most quality replacement sensors will have a slight amount of anti-seize compound on the threads of the sensors right out of the box. Don't get the compound onto the thimble tip of the sensor. If the sensor does not have compound on the threads, it's recommended to put a little on them for future replacement repairs.

Tighten the sensor using the ratchet or wrench. Be extremely careful not to overtighten the sensor. The threads are very delicate and there are only four or five threads, so it's easy to strip them out. Tighten them snug only. Plug the sensor wire back into the wire harness.

Remove the wheel block and lower the truck to the ground. Close the hood and drive the truck as normal. The service engine soon light will reset within 50 to 100 miles, or you can take it back to the parts store and have it reset for you.

Items you will need

  • Car ramps

  • Wheel block

  • Oxygen sensor socket

  • Flex-head ratchet

  • 22-mm box-end wrench

  • Penetrating lubricant

  • Replacement OEM style oxygen sensor(s)

 How to Change the Oxygen Sensor in a Chrysler 300M

Raise the 300M using the jack and set it down on four jack stands, one on each corner. Crawl underneath the car and locate the oxygen sensors. These are three inches long, with wires running out the ends. They are located on the exhaust, one on each side of the transmission.

Unplug the electrical connection to the sensor using your hands. Remove the oxygen sensor from the exhaust using the oxygen sensor wrench, then discard the old sensor.

Apply anti-seize compound to the threads at the end of the oxygen sensor, then install it into the exhaust tubing. Install it first by hand, then use the oxygen sensor wrench.

Repeat Steps 2-3 for the remaining oxygen sensor if necessary. Lower the 300M off of the stands and set it on the ground using the jack.

Items you will need

  • Jack

  • Jack stands

  • Oxygen sensor wrench

  • Replacement oxygen sensor

  • Anti-seize compound

 How to Change the Oxygen Sensor on 3.3L Dodge

Removing the Oxygen Sensor

Disconnect the ground cable from the negative battery terminal by loosening the retaining bolt with a wrench. Pull the clamp off the terminal.

Raise the front of the vehicle using an automotive jack. Support with jack stands placed underneath the front frame.

Locate the oxygen sensor. It will be screwed into the intake manifold near the flange that connects the exhaust manifold to the head pipe.

Separate the wiring connector on the oxygen sensor from the engine wiring harness, by pressing in both tabs with you hands. Then pull the two sides of the connector apart.

Unscrew the oxygen sensor from the exhaust manifold using an oxygen sensor removal socket and breaker bar. The oxygen sensor socket features a slot along the side to facilitate removing the socket without damaging the wiring harness.

Installing the Oxygen Sensor

Screw the new oxygen sensor into the exhaust manifold, using the oxygen sensor socket.

Plug the oxygen sensor wiring connector onto the engine wiring harness connector using your hand.

Lower the vehicle.

Reconnect the ground cable to the negative battery terminal by sliding the clamp over the terminal. Tighten the retaining bolt using a wrench.

Items you will need

  • Wrench set

  • Automotive Jack

  • Jack stands

  • Oxygen sensor socket

  • Breaker bar

 How to Replace an Oxygen Sensor on a Lexus GS300

Raise the vehicle up in the air using the jack and secure it on jack stands. Double-check that the vehicle is secure prior to crawling underneath it.

Locate the oxygen sensors underneath the vehicle. They are small nipples that extend perpendicularly to the exhaust tubing and have a wire lead at the base. Manually unplug the harness leading out of one of the sensors.

Place the oxygen sensor socket onto the end of a 3/8-inch ratchet and place it over the oxygen sensor. There is a slot on the oxygen sensor socket that will allow the wire lead from the oxygen sensor to run out the side and not get damaged. Remove the oxygen sensor and discard it.

Place the replacement oxygen sensor in the bung on the exhaust and tighten it in place using the oxygen sensor socket and the ratchet. Reconnect the wiring harness to the pigtail on the sensor. Repeat the process for any additional sensors on the exhaust.

Items you will need

  • Jack

  • Jack stands

  • Oxygen sensor socket

  • 3/8-inch ratchet

  • Replacement oxygen sensor

 How to Replace an Oxygen Sensor on 2005 Subaru Outback

Removing the Old Oxygen Sensor

Start the engine and let it warm up for about 15 minutes or, if you prefer, run an errand and plan on replacing the oxygen sensor as soon as you are back home. Working on a warmed engine reduces the possibility of stripping the exhaust pipe threads as you remove the sensor.

Open the hood and disconnect the ground (black) battery cable with a wrench.

Take the air intake duct off the air intake assembly at the top of the engine with a flat-head screwdriver, if you have the 2.5L engine model. This will give you access to the oxygen sensor electrical connector.

Locate the oxygen sensor connected to the exhaust pipe. Follow the pipe attached to the exhaust manifold. The sensor has a cylindrical body, about the size of a spark plug and three wires coming out of the rear of the sensor that lead to an electrical connector.

Unplug the sensor’s electrical connector.

Lift the front of the Outback with a floor jack and support it with two jack stands.

Put on your goggles, crawl under the vehicle and remove the engine undercover with a ratchet, short ratchet extension and socket.

Put on your working gloves and unfasten the oxygen sensor form the exhaust pipe with a ratchet and an oxygen-sensor socket.

Installing the New Oxygen Sensor

Coat the threads of the new oxygen sensor with anti-seize compound, being careful not to get any compound on the tip of the sensor, and start the sensor into the exhaust pipe by hand.

Tighten the oxygen sensor with the ratchet and oxygen-sensor socket.

Reinstall the engine undercover with the ratchet, short ratchet extension and socket.

Lower your Outback off the jack stands.

Plug in the sensor’s electrical connector.

Replace the air intake duct with the flat-head screwdriver, if you have the 2.5L engine model.

Reconnect the ground (black) battery cable with the wrench.

Items you will need

  • Wrench

  • Flat-head screwdriver

  • Floor jack

  • 2 jack stands

  • Goggles

  • Ratchet

  • Short ratchet extension

  • Socket

  • Oxygen-sensor socket

  • Anti-seize compound

About the Author

This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information. To submit your questions or ideas, or to simply learn more about It Still Runs, contact us.