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Q: Service engine light is on

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I'm trying to figure out if i need to replace the catalytic converter or is it the oxygen sensor. Should i replace the oxygen sensor first and if so how do i know which one to replace because my car has two oxygen sensors????

My car has 150000 miles.
My car has an automatic transmission.

Hi There, Generally when the check engine light is on, it will register a code in the computer indicating which oxygen sensor is bad. i would suggest starting with replacing oxygen sensors first as this is much more common to fail than a catalytic converter and is much less expensive to repair. I would recommend having a professional from YourMechanic come to your location to diagnose using a scanning tool which should more specifically narrow down what the cause for the check engine light might be.

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