Car PartsOxygen Sensor

Aftermarket & OEM Oxygen Sensor

How can you tell if your oxygen sensor is bad?

It's hard to tell which came first: the check engine light or the faulty oxygen sensor - they go hand in hand. The O2 sensor can get very dirty over time, and it could fail to report accurately. Eventually, it will burn out completely and require replacement. Since the oxygen sensor monitors particulate emissions and regulates the air/fuel mixture to comply with regulations, if it has failed or is failing you risk sending an overdose of hydrocarbons, carbon monoxide, or mono-nitrogen oxides into the atmosphere. And if you are located in a climate where you need the car to warm up in your garage in the morning, you are filling that space with deadly gas. At best, your fuel consumption will elevate, gas mileage will decline, and you won't pass your next round of emissions testing. That is why your check engine light goes on; it's a warning. And when it does, the problem needs to be diagnosed so you know exactly what you need to fix. So if your oxygen sensor or air/fuel ratio sensor is determined to be faulty or dead, you really should get it changed as soon as possible.

O2 sensors and their roll in your emissions system.

New Oxygen SensorsOxygen sensors were invented in the 1960's by Bosch, and designed for use in their fuel injection systems. Early designs used a ceramic-coated zirconia element surrounded by a platinum thimble that used the car's exhaust gas to heat it up, while current designs use an internally-heated planar-style ceramic element which provides much more rapid and accurate reports. They work together to measure concentrations of oxygen in an engine's exhaust gas, and will report to the engine control module so that it can adjust the air/fuel mixture to compensate for irregularities. Oxygen sensors are also in charge of monitoring the performance of the catalytic converter which removes particulates from exhaust gasses, and will alert the vehicle's onboard diagnostic computer when it is below standard. Clearly, the performance of your engine's electronic fuel injection system (relating to fuel economy, horsepower, and emissions) depends on the accuracy of the reporting of these oxygen sensors.

One of the simplest D.I.Y. jobs you'll ever do.

The hardest part of changing an oxygen sensor is identifying which one needs to be replaced. Any mechanic with an OBD-II reader can sort through the trouble codes and make that determination.
  • Once you have located the bad oxygen sensor, you now must follow the wire harness all the way back to where it connects to the ECU. This is easiest when the car is cool and on a lift or jack stands.
  • Now unplug the connector from the module, and unscrew the sensor from your exhaust pipe or manifold.
  • Next, screw the new oxygen sensor in. Make sure you don't over tighten, since the bung will get tighter as it heats up.
  • Finally, connect the wire harness to the ECU and re-test using the OBD-II reader. There should be no more check engine light.

Get rid of that "check engine" light!

Oxygen and air/fuel ratio sensors are sensitive parts, and are absolutely crucial in order to keep your engine performing at peak efficiency. Sometimes a simple cleaning is enough to restore functionality. However, if you need to replace your oxygen sensor we offer only the best brands in the business. Top quality manufacturers from the US, Japan, and Germany can be found right here at Car Parts Discount, all at our everyday low prices with fast shipping right to your door. So don't delay, order now.

One of Our Most Requested Parts