How to Change a Vehicle's Oxygen Sensor

If your car is not giving you the desired mileage, chances are that your vehicle's oxygen sensor needs r epairing. An oxygen sensor is an important part of the vehicle's engine and emission system. Most cars have a computer system that detects how much oil is required by the engine and transfers the fuel from the fuel tank to the engine. The purpose of the oxygen sensor is to detect the amount of unburned elements in the exhaust pipe and convey this information to the computer controlling the fuel. The computer in turn interprets the reading and provides the right amount of fuel to the engine.

A brand new oxygen sensor can be purchased for $100 and installing it is not as difficult as it looks. The oxygen sensor can be purchased from any local automotive parts store. Many automotive online stores also sell oxygen sensors online. In a single vehicle, there can be more than one oxygen sensor. In most cases, the sizes are also different. Thus, it is a good idea to ask the store experts to give you an oxygen sensor socket that has a split in the middle to allow the cable to fit effectively. 

Tool Required

  • Oxygen Sensor
  • Sensor Socket
  • Generic Code Reader
  • Jack Stands
  • Spray to loosen the oxygen sensor /PB Plaster/ WD-40

Step One: Testing the Oxygen Sensor

Find out whether your hunch about the oxygen sensor malfunctioning is right or wrong. The best way to detect this is by using a code reader. Read the manual thoroughly and attach the code reader to your car's engine. If the reader shows the oxygen sensor needs to be replaced, proceed to the next step. 

Step Two: Raising the Car

Use a jack stand to elevate the car. This is required as the car oxygen sensor is placed near the exhaust. The car being in an elevated state will give you a better view and access to the work area. 

Step Three: Removing Cables from the Battery

Disconnect the cables connected to the battery.

Step Four: Locating the Oxygen Sensor 

Find out the exact location of the oxygen sensor. Once detected, remove the oxygen sensor. Use a specially designed oxygen sensor socket to replace the malfunctioning one. In case your oxygen sensor is dirty and cannot be removed easily, you can use a spray to loosen the oxygen sensor. Apply the spray and leave it on for a few minutes. The spray would work on the dirt particles and loosen them. Once loose, you can easily remove the oxygen sensor and replace it. 

Step Five: Installing the New Sensor

Install the new sensors with the help of a socket and ratchet. Torque the sensor with a torque wrench to about 20 foot-pounds and firmly attach the cable wiring to the sensor.

Additional Tips

  • Use a flashlight as the oxygen sensor is located beneath the engine.
  • This may sound obvious, but there is no harm in mentioning it here. Ensure the vehicle engine is switched off (in case you chose not to disconnect the battery). Never work on the vehicle engine when it is powered on or running.