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Q: O2 sensors

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I have 2 bad o2 sensors. Bank 1 sensor 2 and bank 2 sensor 2. How do i know which ones to purchase? They usually have names like left or right upstream or downstream. Please help. Thanks!

My car has 183000 miles.
My car has an automatic transmission.

A: Bank 1 is the cylinder bank that has number...

Bank 1 is the cylinder bank that has number 1 cylinder. In your case that would be the front bank. Each bank has two oxygen sensors, the upstream sensors are sensor 1 and the downstream sensors are sensor 2. So in your case, you need both downstream sensors. Replacing Oxygen sensors involves working underneath the car and requires some special tooling. If you decide you don’t want to do the job, Call your mechanic to schedule an Oxygen sensor replacement at your home and at your convenience.

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