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Old 12-19-2012, 10:27 AM   #1
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Bank 2 post cat O2 sensor

I'm replacing my bank 2 post cat O2 sensor this weekend. I'm gathering from other posts that this is the rear sensor of the two sensors behind the cat. Is this correct?
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Old 12-19-2012, 12:21 PM   #2
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No, it's not correct. Well,, it could be, but that's not the way to identify the sensor location.

There are four O2 Sensors, one in front of each CAT and one behind.

Bank 1 is the exhaust manifold that is bolted to the front of the engine, Bank 2 is the other one. Sensor 1 is the sensor in front of the CAT, Sensor 2 is after it. Bank2 Sensor2 is the bank of exhaust on the rear of the engine, and the sensor after the CAT. This may or may not be the rear of the two sensors after the CAT. You are on the right track, but your method of identificatin could have you working on the wrong part. My method will always put you on the right part.

Good luck. It should be pretty easy.

My logic says that if you need one of the Sensor2s, odds are high that you need them both.

Also, DO NOT USE the type of sensor that has you splice wires, pay a little extra and get the type that plugs in. The reason is that the sensors generate very small voltages, and if you do not do an absolutely perfect splice job, the result can be false errors reported by the sensor that will drive you crazy.
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Old 12-19-2012, 12:54 PM   #3
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Originally Posted by BSL325CI View Post
I'm replacing my bank 2 post cat O2 sensor this weekend. I'm gathering from other posts that this is the rear sensor of the two sensors behind the cat. Is this correct?
Sensor 2 at the top right hand corner of the diagram which is the manifold furthest from the fornt of the car.

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