# audi a3 8l 1.8t aum o2 sensors



## fitonmuji (11 mo ago)

hello everyone i'm confused about some things about my car especially about o2 sensors i have some questions
are the o2 sensors the same in aum engines because I have a problem with them lately and I do not know what kind to buy to change them or maybe they have a part number it would be very helpful to have two and I do not know if they have any difference and can you tell me what function the first has and what the second has or do they have the same function
thanks.


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## Darepoole (Sep 3, 2019)

There is two different lengths for the oxygen sensors front and rear usually. I'm from the states and we didn't get the a3 8l so I'm not sure about the part numbers. The front(main) oxygen sensor is used to calibrate air fuel ratio. this oxygen sensor is the most important and causes running issues when it doesn't function properly. The rear (secondary) oxygen sensor are just there for emissions purpose, they confirm that the catalytic converter is working properly.


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