With a properly functioning Kia oxygen sensor, your engine will have the ability to perform optimally at any altitude you might be traveling by making on the fly adjustments to the air/fuel ratio. The oxygen sensor's location on your engine can be found by observing the component that is sticking out of the exhaust pipe just below the exhaust manifold. Many cars will also have one near or after the catalytic converter. The Kia oxygen sensor supplies the onboard computer with the correct ratio of oxygen in the exhaust gases as compared to that is currently present in the atmosphere around the vehicle. Depending on this reading the Kia onboard computer will either richen the air to fuel ratio or lean it out. The failing of the oxygen sensor will be indicated just like any other sensor on your Kia, the check engine light will illuminate on the dash board instrument panel. Each sensor has a specific code that will be stored in the onboard computer ready for retrieval. Once it is determined the oxygen sensor has failed it has to be replaced. Failure to do so will hinder the onboard computers ability to provide the correct air to fuel mixture to the combustion chambers. Your Kia will also fail the emission test required by your local authorities. The replacement of the oxygen sensor is generally carried out by the owner of the vehicle. The first step is to disconnect the battery. This will clear the codes stored in the onboard computer and make it safe to handle the electronic component you are about to remove. With the wire to the sensor disconnected, it can be removed with the aid of a wrench. Once the new sensor is in place on your Kia, you are ready for the emission inspection.