Code po133

2005 CHEVROLET OPTRA
170,000 MILES • 2.0L • 4 CYL • 2WD • AUTOMATIC
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MICHEBRU
  • MEMBER
  • 1 POST
Have a code po133. I want to know which one the top or bottom?
Aug 2, 2018 at 2:33 PM
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DANNY L
  • CERTIFIED EXPERT
  • 5,648 POSTS
Hello, I am Danny.

That would be Bank 1 Sensor 1 (Upstream-Top). I have attached a picture of location (circled in red) and also a link showing how to replace. Hope this helps and feel free to ask any other questions if needed. Thanks for using 2CarPros.
Danny-

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor
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Aug 2, 2018 at 4:36 PM