With the data being supplied by the Mitsubishi oxygen sensor, the correct adjustments can be made to the fuel system so the best possible mileage can be obtained and highest power can be produced. The oxygen sensor takes a reading of the exhaust gases and compares it to the oxygen level of the air around the vehicle on a constant basis. As the oxygen levels of both vary, the correct leaning or enriching of the air to fuel mixture can occur. Because the Mitsubishi oxygen sensor is an electronic component, it will fail periodically and be in need of replacement. The owner of the Mitsubishi will become aware of a problem when the check engine light is illuminated on the dash. When this light goes on, a code is simultaneously sent to the onboard computer. This code will properly identify the problem as a faulty oxygen sensor. A list of what each code represents is located in the service manual of your vehicle. Each model has its own set of codes, so the correct manual is required to translate a numerical number to a specific part. The replacement of the oxygen sensor, once the code has been retrieved, is very simple and only requires the use of a single wrench. Because this sensor is an electrical component, the battery should be disconnected before this sensor is unplugged and removed from your Mitsubishi. This will remove the possibility of an electrical shock occurring to the person replacing the oxygen sensor. It will also clear the stored codes in the onboard computer so the check engine light will no longer be illuminated. With the sensors replaced on your Mitsubishi, the engine should be able to perform at its maximum level while achieving the best possible fuel mileage while on the road. Just make sure you don't start this job until your exhaust pipe has cooled down.