The 20.9 Percent Factor (Oxygen Sensor)

Do you know what gas makes up 20.9% of the air we breathe? It's oxygen.   Oxygen is an important part of the combustion process that enables your engine to make power.  The amount of oxygen in the exhaust provides clues as to how well your engine is running.  Your vehicle has oxygen sensors that provide the engine computer with the information it needs to adjust the combustion process.

Many vehicles have more than one oxygen sensor.  They are positioned in the exhaust system, one between the engine and the catalytic converter, and another after the catalytic converter.  An onboard computer compares the oxygen levels before and after the catalytic converter to determine if the converter is working properly.

An oxygen sensor may fail for many reasons.  You could have bad fuel that contaminated it.  Your sensor may have simply worn out.  Your engine may be burning oil, and that soot can ruin the sensor.  Road contaminants, like salt and water, can corrode the sensor. 

There are signs that your oxygen sensors may be going bad.  You may see your Check Engine illuminated.  A trained technician at your NAPA AutoCare Center can retrieve a diagnostic code generated by your engine computer.  Another sign is that your engine may be running rough.  If you spot black, sooty smoke coming out of the tailpipe or notice your fuel economy has plunged, that could be a sign.

If you see any of these signs, head on over to your auto Care Center.  They have the equipment and training to track down the problem.  Simply replacing the oxygen sensor is often not enough; the technician will have to get to the root of what's causing the sensor to fail and repair that as well. 

That gas that makes up 20.9% of the air could hold the key to your vehicle running at 100%.  Make sure your oxygen sensors are working the way they should.


Oxygen , O2
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