O2 Sensor Position

[OnAFly]

I'm getting a code P0430 on my 2008 Silverado saying my Bank 2 sensor is failing.

Which side is Bank 2? Is it possible to tell if it's the upstreeam or downstream from the computer?

[Jeremy airjer W]

Bank 1 is always the same side of the engine as the number one cylinder. Bank two is the other side. So bank 2 on a 5.3 liter would be the passenger side of the engine.

P0430 is a cat inefficiency code. It is likely not the O2 sensor and more likely the catalytic converter. There should be an 8 year 80,000 mile warranty on the federal emissions system so contact your dealer before you do anything.

[OnAFly]

Really! I'm passed 80K, so...

From ODBCodes dot com:

A code P0430 may mean that one or more of the following has happened:

* The catalytic converter is no longer functioning properly

* An oxygen sensor is not reading (functioning) properly

* There is an exhaust leak

Looks like either of these could be the case. What are the chances it's the cat? If 90% of the time it's a sensor, I don't want to pay for a cat if I don't need one.

[Jeremy airjer W]

Here's how you know if its the sensor. With the engine running watch the rear O2 data on the scan tool. If the bank 2 sensor 2 O2 sensor is ready a steady higher voltage than the Bank 1 sensor 2 O2 sensor than there is a pretty good chance that it may be the O2 sensor. If the Bank 2 sensor 2 is switching similar to the bank 2 sensor 1 O2 sensor than the cat is bad.

I would say 99% of the time it is the catalytic converter.

[Macgyver55]

If the Bank 2 sensor 2 is switching similar to the bank 2 sensor 2 O2 sensor than the cat is bad.

Do you mean If the Bank 2 sensor 2 is switching similar to the bank (1) sensor 2 O2 sensor than the cat is bad?

[Jeremy airjer W]

Nope, if bank 2 sensor 2 is switching similar to bank 2 sensor 1 is what I meant. I corrected the original post.

[Macgyver55]

gotcha, you had me confused on which way you meant!

[Jeremy airjer W]

I had myself confused for a second!

[OnAFly]

Thanks for the info...hoping for the O2 to be the problem