How to Replace Exhaust Sensors on a Nissan

The oxygen sensors (O2S) on your Nissan monitor the oxygen content of the exhaust gas stream coming out of the combustion chambers. The computer uses this and other sensors' information to calculate the best air/fuel mixture at any given time for best engine performance. However, O2 sensors wear out, affecting engine efficiency. Depending on your particular model, your Nissan may come equipped with two or three oxygen sensors. Make sure to locate the one(s) you need to replace before beginning the job.
Difficulty: Moderately Easy
Instructions
Things You'll Need
Floor jack, if necessary
2 jack stands, if necessary
Goggles, if necessary
Box-end wrench or oxygen sensor socket, if necessary
Wrench or ratchet and socket, if necessary
Anti-seize compound, if necessary
New oxygen sensor gasket, if necessary
Scan tool, if necessary
Removing the Oxygen Sensor(s)
1

Park your car in a level surface.
2

Start the engine and let it idle for about 15 minutes or drive your Nissan for about 15 to 20 miles prior to replacing the sensor(s). This will bring the engine and exhaust system to operating temperature and help you avoid using excessive force to remove the sensor(s), which may damage the exhaust pipe threads.
3

Disconnect the ground (black) battery cable using a wrench.
4

Raise the front of your Nissan using a floor jack and support it on jack stands, if you are replacing a downstream oxygen sensor. This sensor is located at the outlet pipe of the catalytic converter, under the vehicle. The upstream sensor threads either to the exhaust manifold or down exhaust pipe, close to the manifold, and usually you do not have to lift the car to replace it.
5

Put on your goggles if you are replacing a downstream oxygen sensor. Rust particles may fall and injure your eyes as you work underneath your vehicle. Also, wear long sleeves, if necessary, since you will be working around a hot exhaust system.
6

Unplug the oxygen sensor electrical connector. On some Nissan models, you will have to remove the passenger seat and look for the connector under the carpet, to disconnect the downstream sensor.
7

Unscrew the sensor using a box-end wrench or oxygen sensor socket, if your Nissan model has the screw-in type. With flange type sensors, unscrew the two hold-down nuts or bolts suing a wrench or ratchet and socket.
8

Remove the oxygen sensor from the vehicle. Flange type sensors come equipped with a gasket. Make sure to remove it as well.
Installing the Oxygen Sensor(s)
1

Coat lightly the threads of the new sensor (screw-in type) with anti-seize compound, if your new sensor does not come with it already. This will help your remove the sensor next time you need to replace it. Be careful not to let the compound come in contact with the sensor's tip to avoid damage to the active elements inside.
2

Place the new sensor in place and start threading the sensor or mounting nuts/bolts by hand. If you are replacing a flange type, use a new gasket.
3

Tighten the sensor using the box-end wrench, oxygen sensor socket (screw-in type), wrench or ratchet and socket (flange type).
4

Plug the oxygen sensor electrical connector. Replace the carpet and passenger seat, if you had to remove them.
5

Lower the vehicle, if you had to raise it.
6

Connect the ground (black) battery cable using the wrench.
7

Start the engine and make sure the Check Engine Light is off. Otherwise, you will need to erase any Diagnostic Trouble Codes (DTC's) stored in the computer's memory using a scan tool.