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How to replace an oxygen sensor

If your oxygen sensor malfunctions, your vehicle's power and performance will go down the tubes. Luckily, replacing it yourself is easy and inexpensive.

What does an O² Sensor do? 

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.

Getting Started

Parts you'll need:

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

Safety Comes First

Every vehicle is different. When it comes to maintenance and repairs, always follow the vehicle's owner's manual. 

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. 

  1. Disconnect the ground battery cable.
  2. Raise and support the vehicle securely on jack stands.
  3. Disconnect the electrical connector from the 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.