# Bank 1 and Bank 2 issue

**URL:** <https://community.cartalk.com/t/bank-1-and-bank-2-issue/181605>\
**Category:** Maintenance/Repairs\
**Tags:** volkswagen, routan\
**Created:** [January 3, 2022, 4:57am UTC](https://community.cartalk.com/t/bank-1-and-bank-2-issue/181605 "2022-01-03T04:57:21Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![afmedic73\_178829](https://avatars.discourse-cdn.com/v4/letter/a/e9a140/32.png) [@afmedic73\_178829](https://community.cartalk.com/u/afmedic73_178829)\
**Post date:** [January 3, 2022, 4:57am UTC](https://community.cartalk.com/t/bank-1-and-bank-2-issue/181605/1 "2022-01-03T04:57:21Z")

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Hello,  
Can anyone take a look at the live readings below for my Bank 1 and Bank 2 O2 sensors and tell me what I’m to look for? Is the voltage going jump around like this? You can see that Bank 1 sensor 2 is very stable, the other are all over the place. I now have a P0430 code Catalyst efficiency below threshold Bank 2. I’ve replaced all the o2 sensors (4) about 6 months ago. The vehicle is a 2009 Volkswagen routan, which if you did not know has the Chrysler 4.0 engine similar to the caravan, and town and country. Thank you

Tim D.

 ![Screenshot 2022-01-02 205022](https://global.discourse-cdn.com/cartalk/original/3X/e/7/e79af3b2a30fd2ca5e27193c609572f3b6a02df3.png)

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [January 3, 2022, 5:32am UTC](https://community.cartalk.com/t/bank-1-and-bank-2-issue/181605/2 "2022-01-03T05:32:16Z")

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The voltage for the O2 sensor(s) before the cat are going to bounce.

The voltage for the O2 sensor after the cat is going to hold pretty steady,

[![](https://global.discourse-cdn.com/cartalk/original/3X/9/2/920c82aae79279b7169d496b337e65aa8eb81476.jpeg "Using upstream and downstream oxygen sensors to test the catalytic converter") ](https://www.youtube.com/watch?v=KGpMzdEO5KY)

Tester

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<div class="post-metadata">

**Author:** ![afmedic73\_178829](https://avatars.discourse-cdn.com/v4/letter/a/e9a140/32.png) [@afmedic73\_178829](https://community.cartalk.com/u/afmedic73_178829)\
**Post date:** [January 3, 2022, 6:29am UTC](https://community.cartalk.com/t/bank-1-and-bank-2-issue/181605/3 "2022-01-03T06:29:05Z")

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Thank you, so it appears possibly my Bank 2 Cat is bad since by downstream voltages are bouncing /matching my upstream.

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [January 3, 2022, 6:42am UTC](https://community.cartalk.com/t/bank-1-and-bank-2-issue/181605/4 "2022-01-03T06:42:30Z")

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I don’t see a bank 2, O2 sensor 2 reading?

Tester

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**Author:** ![afmedic73\_178829](https://avatars.discourse-cdn.com/v4/letter/a/e9a140/32.png) [@afmedic73\_178829](https://community.cartalk.com/u/afmedic73_178829)\
**Post date:** [January 3, 2022, 6:51am UTC](https://community.cartalk.com/t/bank-1-and-bank-2-issue/181605/5 "2022-01-03T06:51:51Z")

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Column G on the screen shot

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<div class="post-metadata">

**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [January 3, 2022, 6:58am UTC](https://community.cartalk.com/t/bank-1-and-bank-2-issue/181605/6 "2022-01-03T06:58:17Z")

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It;s starting to switch with upstream.

The converter is bad.

Tester