An oxygen sensor, also known as an O2 sensor, is used by your vehicle’s computer to control and determine the proper fuel-air ratio that is being pumped into your engine. A defective oxygen sensor will cause a dry fuel/air mixture, which in turn leads to an increase in harmful emissions from your exhaust system. The O2 sensors are designed to be replaced every 90,000 miles (144,837 km) or less, and because of this, they are considered to be “disposable” parts. In short, you can “fix” a defective or damaged oxygen sensor by replacing it. Fortunately, it is not difficult or costly to replace an O2 sensor.
- Locate your defective oxygen sensors. Older vehicles, before 1990, will usually have a single oxygen sensor located in front of the catalytic converter in the exhaust manifold. The new vehicles will have two oxygen sensors, one just before the catalytic converter and one later. The dual exhaust systems of vehicles will have two sets of oxygen sensors with the same arrangement. In most vehicles, the O2 sensor will look like a type of gold or brass plug with a group of wires coming out of the tip.
- Disconnect the wires from your oxygen sensor, from where they connect to the electrical harness of your vehicle. Be careful when disconnecting them from not damaging or destroying the electrical connector in your car, as this will make your new O2 sensor not work correctly.
- Use your key or ratchet to remove the old sensor. You may have to exert additional force since oxygen sensors have a tendency to stick or “freeze” and do not turn quickly until they are released. Discard the old sensor when you have managed to remove it.
- Cover the threads of your new O2 sensor with WD-40 or similar lubricating oil. Do the same for the wires in the exhaust manifold. This is to ensure trouble-free installation and to ensure you do not damage the threads when you screw them into the new sensor.
- Screw the new O2 sensor into the exhaust manifold and connect the wires to the electrical outlet. Your O2 sensor has been installed correctly.
If you can not get the old sensor off, spray an abundant amount of penetrating oil over the place where the sensor is screwed into the manifold and let it sit for about ten minutes. This will allow the oil to lubricate the threads and will enable you to release the sensor.