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How To Replace an Oxygen Sensor

The oxygen sensor is one of the most important sensors on your vehicle. It monitors the amount of oxygen in the engine’s exhaust gas and is usually located on the exhaust manifold. Most oxygen sensors operate like a small battery. Differences in oxygen content between the sensors' inner and outer surfaces cause it to generate a small voltage signal. 

The sensor is electrically heated internally for faster switching when the engine is running. When there’s a lot of oxygen (lean) present, the sensor produces a low voltage signal; when there’s little oxygen (rich), it produces a signal of higher voltage. By monitoring the oxygen content and converting it to electrical voltage, the sensor acts as a lean-rich switch. 

If you’ve noticed a decline in your engine’s performance in addition to stalling or backfiring, it could be time to replace your O2 sensor. 


Here’s What You’ll Need:

  • O2 Sensor Socket
  • Wrench Set
  • Jack Stands
  • Jack
  • O2 Sensor Anti-seize Compound

Words of Wisdom From The King: 

  • Every vehicle is different. Always follow the owner’s manual when it comes to maintenance and repairs.

  • Safety should be your number one priority. Don’t smoke, drink alcoholic beverages, or wear a necktie while working on the car. Watch out for hot objects, sharp instruments, hazardous materials and other potential safety hazards in and around your workspace.

  • Don’t work with a Philips when the job calls for a flat. Substituting tools can compromise your safety or your vehicle’s performance.

  • Finally, when the fun turns to frustration, or if the job requires specialized knowledge beyond your capabilities, please do not attempt it yourself. Talk to a professional mechanic or installer.


Steps For Replacing an Oxygen Sensor 

Steps for Removing Your Old O2 Sensor

  1. Disconnect the ground battery cable.
  2. Raise and support the vehicle securely on jack stands (see our DIY on How to Jack Up a Vehicle)
  3. Disconnect the electrical connector from the O2 sensor

Steps For Replacing an Oxygen Sensor 

Steps for Installing Your New O2 Sensor

  1. Apply anti-seize compound to the threads of the new sensor.
  2. Install new O2 sensor and tighten to specified torque.
  3. Reconnect the electrical connector.
  4. Lower the vehicle.
  5. Take the vehicle for a test drive to ensure everything is running smoothly.