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The 3.3L Dodge engine is a front wheel drive V6 engine that was first introduced in 1990 for use in Dodge mini-vans and front wheel drive cars. The oxygen sensor on these vehicles is a small sensor located in the exhaust manifold. The oxygen sensor measures the amount of unburned oxygen in the exhaust. This measurement allows the engine computer to adjust the air fuel ratio for optimal efficiency.

Instructions

Removing the Oxygen Sensor

1

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

2

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

3

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

4

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.

5

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

6

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

7

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

8

Lower the vehicle.

9

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

A fuel-injected engine uses many different sensors to determine how to make your engine run properly. The 1987 and newer GM trucks use one or more oxygen sensors located along the exhaust. Theyre not difficult to replace, but they can take some elbow grease and some basic safety equipment to do properly.

Instructions

Lift the Truck

1

First, make sure the vehicle is turned off, has cooled down for a few hours and the emergency brake is set. Using a jack, lift the front of the truck so that the front tires are off the ground. A good jack point is the front crossmember, or alternatively, the sides of the frame below the doors.

2

With the truck properly supported, slide underneath the vehicle and look for the O2 sensor. Depending on the year of the truck, there will be just one sensor located on the passenger side near the transmission, or several sensors on the later models, located both before and after the catalytic converters. Theyre easy to spot, as they stick out about 2 inches from the exhaust tubing and have two wires coming out from the body.

3

Unplug the harness that connects the O2 sensor to the stock wiring. If the clip that holds the harness together is difficult to disconnect, use a small flathead screwdriver to pop it free.

4

Using an O2 sensor socket or an appropriately sized wrench, loosen and remove the old O2 sensor. It unthreads like any other bolt would, going to the left to loosen. Should the sensor be stuck in the threads, loosen them with some WD-40 or similar product. Should the sensor still not come loose, the bung can be cut out of the exhaust, but it will have to be welded back into place by a professional, and should only be done as a last resort.

5

Before installing the replacement O2 sensor, put some anti-seize compound around the threaded area of the sensor. This will help you the next time you have to replace the sensor, as the heat of the exhaust wont cause the threads to seize up on you.

6

To reinstall, thread the O2 sensor into the bung on the exhaust, reconnect the wiring and lower the truck off of the jackstands.

The oxygen sensor in a car is now an integral part of the exhaust system. Although it has been around for many years--since the implementation of On-Board-Diagnostics II in 1996--the amount of oxygen sensors per car has doubled. Finding them for replacement is now much trickier.

Location

The oxygen sensors are located directly in the exhaust system, usually by portholes that the sensor screws into on the exhaust pipes--and in some cases, on the exhaust manifold. The exterior portion of the sensor provides a wire and plug that plugs the harness into the ECU and transmits the voltage for monitoring.

History

Designed in the 1960s by a Robert Bosch, the oxygen sensor in a car made its first introduction in the late 1970s on a Volvo that also introduced the 3-way-catalyst system. By 1981, to reduce emissions, all vehicles were being manufactured with catalytic converters.

Function

The function of the oxygen sensor (also known as the Lambda sensor) is to monitor the amount of fuel-to-air mix in the combustible engine of a vehicle. The sensor transmits voltage and the engine management computer (ECU) monitors the ratio. There is an ideal ratio--when a sensor fails or there is an internal problem with the engine, more pollutants emit from the exhaust.

Types

The older sensors were "unheated" sensors. Since they do not transmit voltage until their internal temperature reaches 600 degrees Fahrenheit or more, this allows a period of time in between the ECU being able to monitor the sensor. "Heated" sensors are common today, have extra wires for the heating element and assist in heating the sensor more rapidly.

Considerations

If replacing an oxygen sensor, a direct-fit replacement is far superior to the "universal" sensor which would require cutting, identifying and splicing the wires of the sensor. The direct-fit sensor provides the necessary wires and plug to fit the plug of the wire harness easily.

The 1999 Saturn SL features a four-cylinder, 1.9-liter engine with two oxygen sensors that monitor the exhaust emissions. One is located directly into the manifold and can be accessed and replaced from the engine compartment. The other is located just behind the catalytic converter in the converter/front flex-pipe assembly. Because of the easier access to the "upstream" sensor (in the manifold), the sensor is actually easier to replace than the "downstream" sensor (near the converter), unlike the case with many other vehicles, which require you to get under the vehicle to replace any oxygen sensor.

Instructions

Downstream Sensor

1

Place a wheel chock behind one of the rear tires and then apply the parking brake to the Saturn SL.

2

Lift the drivers-side front quarter of the vehicle with a jack high enough to place a jack stand under the front frame rail (place it up in front of the converter to keep it out of the way of the work space). Repeat the procedure for the passenger-side front quarter to elevate the front axle.

3

Put on safety glasses and crawl under the front-center of the Saturn to the location of the steering rack just above the catalytic converter shell. The downstream sensor wire will be visible. The wire runs along the drivers-side edge of the converters heat shield and its plug connection is fastened up near the steering rack. Reach up to lift the wire harness plug clip lock while pulling the sensor wire mating plug free.

4

Snip the zip tie retainers of the wire down the length of the sensor wire. Repositioning from under the front-center over to the drivers side may help you reach the lower downstream zip ties to the sensor location.

5

Slide the heat-resistant cover off the oxygen sensor wire.

6

Align the sensor wire into the slot on the side of the oxygen sensor socket. Place the socket firmly onto the oxygen sensor. The small heat shield for the sensor makes it a tight fit.

7

Attach the ratchet to the socket and turn the sensor counterclockwise to remove it. It may be stubborn at first, but some leverage and ingenuity will pay off.

8

Hand-thread the new sensor into the oxygen sensor port. Tighten the sensor snugly with the ratchet and socket, again aligning the wire into the slot of the socket. Do not over-tighten or the threads of the sensor may strip.

9

Slide the original heat-resistant wire cover over the plug connection of the new sensor and feed it down to the sensor.

10

Plug the sensor back into the wire harness mating plug.

11

Zip-tie the wire to the heat shield, so it does not droop, before lowering the Saturn back to the ground.

Upstream Sensor

12

Open the hood and locate the upstream sensor. Its clearly visible in the front-center of the engine placed at the top of the manifold.

13

Disconnect the sensor harness plug from the wire harness mating plug located (and affixed) to the fan shroud. Lift the lock on the wire harness side of the plug and pull the socket wire plug away.

14

Place the socket onto the sensor, aligning the single wire into the slot of the socket.

15

Place the ratchet on the socket and turn counterclockwise to remove.

16

Place the new sensor into the sensor port, hand-tighten and the snugly tighten with the ratchet and socket before plugging the sensor into the wire harness mating plug. Close the hood.

The oxygen sensor monitors the fuel-to-air ratio in the spent exhaust near or on the manifold. Since the integration of OBD II (on-board diagnostics) in 1996, the amount of oxygen sensors on vehicles has doubled. Upstream sensors still monitor the exhaust from the manifold; downstream sensors now monitor the catalyst efficiency near the catalytic converters. While replacing some oxygen sensors is a simple task, vehicle designs can frustrate the most seasoned mechanics when it comes to replacing them due to lack of access. Tool companies advance along with technology. Luckily, theres always the right tool for the job.

The Environment of the Oxygen Sensor

Most oxygen sensors screw into portholes or bungs in the exhaust system. Due to extreme heat from the exhaust of the combustion engine, the pipes of the exhaust system heat up when operating and then cool down after the vehicle is shut off. This creates an unfriendly environment for the metals of the exhaust pipe and the threads of the oxygen sensor. Even sensors that are easily accessible can provide a high degree of difficulty when trying to be unscrewed from the exhaust pipe.

Tools and Taps

Rest assured that there is the right tool to remove the most challengingly accessible oxygen sensor. While many offer easy access, todays tools will offer you a variety of choices as well as combining other common tools in order to successfully remove oxygen sensors.

Oxygen sensor wrench with flex heads are now available. Oxygen sensor sockets with slotted edges are also quite popular. Wrenches that fit onto the hex-head of the sensor--most commonly a 22-mm or a 7/8-inch drive--accompanied with a square drive in the wrench to accommodate a ratchet extension can be used. Swivels are another friendly tool for access-challenged sensors. And in the easiest ones to remove, a box-end wrench can even be used.

Always unplug the wire harness of the sensor before attempting to remove it.

A Little Heat Might Help

So now, youve found the right tool or the right combination, youve unplugged the wire and placed it through the wrench or into the slot of the socket and the sensor is still stuck. While some suggest heating up the engine by running it will help, the fact is, under this procedure, the heat expands both the exhaust pipe and the sensor threads. Penetrating lubricant in liberal doses may help in this manner, but if you have a small propane or oxyacetylene torch, you can also heat the edges of the bung on the exhaust pipe. This will expand the pipe and bung without greatly affecting the sensor. A little heat will go a long way when removing stubborn sensors.

Its also a good idea to allow the pipe to cool down and then chase or tap the bung with an O2 sensor thread tap or chaser. Commonly an 18-mm diameter with a 1.5-mm thread pitch is used, but check the sensor threads and diameter at the parts store when you buy it to make sure. This will make threading the new sensor easier. Since the threads of oxygen sensors are much weaker than the bung, you can easily damage or cross-thread a new sensor trying to install it without chasing the threads of the bung. Apply a little anti-seize lubricant on the threads of the sensor--being caul not to get any on the head of the sensor--before tightening; although many quality aftermarket sensors will provide some anti-seize compound on the threads for you already.

The oxygen sensor in your 2001 Toyota Tundra may one day go bad and need replacement. The oxygen (O2) sensor is responsible for regulating the oxygen and fuel ratio in your vehicle, contributing to the efficiency of gas usage. If the oxygen sensor goes bad, your Tundra may run poorly and get poor gas mileage. Knowing how to replace it yourself can save you money.

Instructions

Instructions

1

Locate the oxygen sensor on the pre-catalytic converter. This is located near the right-front wheel well of your Tundra.

2

Detach the large air intake pipe that is connected to the air box going to the rear turbo. Also remove the two smaller air pipes connected to the air box running to the blow off. This will give you access to reach the sensor. Soak the oxygen sensor in penetrating oil (WD-40 or similar) to loosen it for easier removal.

3

Use the 7/8-inch wrench to remove the old oxygen sensor. Find the stock sensor wire near the engine lift loop by the firewall. Splice the stock sensor wire and connect it with the wires to the new oxygen sensor using crimp connectors.

4

Apply some of the anti-seize paste to the threads of the new sensor. Be caul not to get any of the paste on the sensor itself or it will ruin it. This will make the oxygen sensor easier to remove the next time.

5

Screw the new sensor in by hand. Fully tighten it with the wrench so it can not be loosened by hand. Reattach the air pipes again.

The oxygen (or O2) sensor on your Toyota helps balance the engines fuel-to-air ratio. A faulty O2 sensor can cause your engine light to come on. It might also prevent the vehicle from starting. Your Toyota is equipped with two O2 sensors. They are located underneath the vehicle on the exhaust pipe, with one on either side of the catalytic converter.

Instructions

1

Set the emergency brake.

2

Jack up the front end of your Toyota. Put the jack stands in place.

3

Slide under the vehicle with the socket set and locate the O2 sensor you will be replacing. Sensor 1 is located on the exhaust pipe, on the left hand side of the catalytic converter. Sensor 2 is located on the right hand side of the catalytic converter closest to the vehicles rear end.

4

Loosen the two mounting bolts that hold the sensor to the exhaust pipe with your socket set.

5

Unplug the sensor from its socket by squeezing in the two safety tabs on the sides of the socket and pulling the sensor free.

6

Plug in the new O2 sensor. Re-mount it to the exhaust pipe with the mounting bolts.

7

Remove the jack stands and lower your Toyota.

You might need to replace the oxygen sensors on your 2002 Hyundai Sonata if you notice your fuel consumption increasing, or if your "check engine" light illuminates. The oxygen sensor measures the amount of oxygen being expelled through the exhaust and adjusts the fuel necessary to meet certain oxygen levels. You have two sensors, one in the manifold and one inline with the catalytic converter. Remove both in the same manner.

Instructions

1

Locate the oxygen sensor in the exhaust manifold or the exhaust pipe next to the catalytic converter. It resembles a spark plug and has one thin wire extending from it. Use the replacement sensor for a visual aid.

2

Push in on the lock on the wire harness at the top of the sensor. Pull the wire off.

3

Remove the sensor with a deep well socket or wrench. Due to the extreme heat generated in the manifold and exhaust pipe, it is common for the sensor to become stuck. If necessary, use spray-on rust breaker such as liquid wrench to aid in the removal process.

4

Place a small amount of anti-seize compound on the threads of the new oxygen sensor and thread the sensor back into the manifold or tail pipe.

5

Push the connector of the wire back onto the oxygen sensor.

The V6 4.3-liter engine of the 2002 Chevrolet Blazer has four oxygen sensors that monitor the fuel-to-air ratio and the catalyst efficiency. Locating the correct oxygen sensor or sensors to replace may be more challenging than actually replacing them. Keep in mind that the bank one sensor is on the same side as the number one cylinder, and the two sensors one (1) are on the front pipe just below the manifold. The two rear sensors are on the passenger side of the SUV; one placed in front of the catalytic converter and one directly behind it. These are referred to as sensors two (2).

Instructions

1

Drive the 2002 Chevrolet Blazer up onto two car ramps, and then apply the parking brake.

2

Place a wheel block behind one of the rear tires.

3

Put the safety glasses on, and crawl underneath the Blazer with the remaining items.

4

Locate the oxygen sensor(s) you intend to replace. The two front ones are located in the front Y-pipe of the exhaust system towards the front of the engine. There is one per side of the Y-pipe. The other two are located before and after the catalytic converter (which is just behind the Y-pipe towards the center of the vehicle on the passenger side).

5

Spray the threads of the oxygen sensor with penetrating lubricant, and allow it to soak in for a few minutes.

6

Follow the wire harness from the oxygen sensor to the plug connection. Use a small forked pry tool to unseat the retaining tab of the plug connection from the frame or undercarriage of the SUV. Disconnect the wire harness plug.

7

Place the plug of the sensor through the box-end side of the 22-mm or 7/8-inch wrench, and then place the wrench onto the hex-headed portion of the sensor.

8

Turn the sensor counterclockwise using the wrench. A quick jerking motion of the wrench should loosen the sensor effectively, but if necessary, start the engine for a couple of minutes to warm up the exhaust system and expand the binding metals of the pipe and sensor. Be careful that it will not heat up the front Y-pipe sensors because they can become hot enough to burn you.

9

Thread the new replacement sensor into the exhaust port by hand as far as it will allow. Tighten the sensor to 30-foot pounds with a torquing hand wrench. Do not over-tighten the sensor, or you will damage the threads.

10

Reconnect the wire harness of the replacement sensor to the plug connection, and then push the retaining tab back into its respective hole in the frame or undercarriage.

The oxygen sensors in the exhaust system of your 1998 Mercury Mountaineer help the fuel system regulate the amount of fuel burned by the engine. If the oxygen sensors fail, you may notice a drastic decrease in the fuel mileage of your truck. The 1998 Mountaineer is equipped with four oxygen sensors. There is a sensor on each side of both catalytic converters. Buy replacement sensors from an auto parts retailer.

Instructions

1

Lift the truck with a jack to support it with jack stands. Locate the oxygen sensors on each side of the dual catalytic converters in the exhaust system.

2

Disconnect the wiring harness at the top of the oxygen sensor. You can pull the connector apart by hand. Remove the oxygen sensor with an oxygen sensor socket and ratchet.

3

Thread the new sensor into place by hand to prevent cross threading. Torque the sensor to 30 pound-feet with your torque wrench. Connect the wiring harness by pressing the electrical connection together.

4

Repeat the process for the remaining sensors you want to change. Raise the truck slightly and remove the jack stands. Lower the truck to the ground.

The oxygen sensor on your Honda Civic is a little electronic device that measures the emissions in your cars exhaust and forwards the information to your Civics on-board computer. The computer then takes those measurements and adjusts the fuel-and-air mixture pumped into the combustion chambers of the engine so as to keep harmful emissions as low as possible. When an oxygen sensor breaks, the computer is unable to determine the proper mixture, so emissions will increase. This can be harmful to the environment and can prove expensive to repair.

Instructions

1

Lift your Civic off the ground using the jack. Because of the oxygen sensors locations on your exhaust manifold, youll need to be under the car to reach them. And because the Civic is so low to the ground, you will not be able to reach the sensors without raising the car.

2

Settle your Civic onto jackstands so that you can work under the car safely without only the jack serving to support the vehicle.

3

Locate your oxygen sensors by starting at the back of the exhaust system and working your way toward the front of the car. The Civic has two oxygen sensors, one located immediately before the catalytic converter and the other located farther up the exhaust manifold past the catalytic converter. They will look like fat golden or brass pegs with a large wire coming out of the tips.

4

Unplug the sensors wire from where it is plugged into the cars wiring harness. Take care not to damage the electrical socket, as doing so may keep your new sensor from working correctly.

5

Use your wrench or ratchet and socket to unscrew the oxygen sensor from the exhaust manifold.

6

Apply WD-40--or a similar lubricating substance--to the threads of the oxygen sensor to ensure a smooth installation.

7

Screw the new oxygen sensor into the exhaust manifold and tighten it down securely. Plug the new sensors wire back into the electrical socket mentioned in step 4.

8

Repeat steps 3 through 7 for the other oxygen sensor.

9

Raise your Civic off the jackstands, then lower it down to the ground.

If your GMC Yukon is running rough or burning through more gas than usual--and especially if these symptoms are combined with an illuminated "check engine" light--you may have a failing oxygen sensor. The oxygen sensor is located just below the manifold, behind the wheel well on the driver side of the Yukon. You can access it easily from beneath the truck. Purchase a new oxygen sensor at an auto parts store or GMC dealership.

Instructions

1

Raise the front end of your GMC Yukon using a jack. Place a set of jack stands beneath the front of the truck to secure it. Remove the jack.

2

Remove the retaining clip from the wiring harness connected to the oxygen sensor by pulling it up to release it. Remove the wiring harness from the sensor. The GMC Yukon uses a wiring harness that pulls free by hand, so carefully pull it upward away from the sensor.

3

Remove the oxygen sensor using an oxygen sensor socket and ratchet. Check the thread area on the truck and wipe it with a clean rag if needed to clear any debris.

4

Insert the new oxygen sensor using the oxygen sensor socket and ratchet. It may be easier to thread it in by hand so that you dont cross-thread the sensor. Torque the sensor to 31 foot-pounds with a torque wrench.

5

Raise the truck with the jack. Remove the jack stands. Lower the truck to the ground.