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Q: O2 Sensor

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Had a warning light come on today. Had the codes pulled. It indicated an O2 sensor is going bad. Wondering how long until it completely fails? What happens when it does.

Thank you.

My car has 113000 miles.
My car has an automatic transmission.

Hi There, There are a number of possible reasons as to what may have caused this code to show up as the O2 sensor reads the exhaust gases that are a product of many different variables. Unfortunately, there is no way to tell exactly how long it may last or not, however if the code has shown up, it is likely that it has already failed and is reading incorrectly. The [oxygen sensors]((https://www.yourmechanic.com/services/oxygen-sensor-replacement) which are part of your emissions system read exhaust gases to determine whether or not the appropriate amount of oxygen is present in the exhaust. Based upon this reading, this information is relayed to the car’s ECU which then makes a determination as to whether or not to add more or less fuel to the engine. When too much or too little oxygen is present, this will cause check engine light to come on. Too much oxygen may be present in the exhaust gas due to things like an exhaust leak, a vacuum leak, a faulty mass air flow sensor (causing a lean fuel condition) or faulty fuel injectors. Too little oxygen may be present in the exhaust gas may be caused by things like a clogged air filter, a failing mass air flow sensor (causing too much fuel to be introduced to the motor), bad fuel injectors or a clogged catalytic converter. When the O2 sensor is not working properly, this will cause false readings to be relayed to the computer causing inaccurate adjustments to be made to the intake and fuel system in your engine. I would suggest having an expert from Your Mechanic come to your home to diagnose your emissions system.

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