Hello, I had a cel pop up and scanned it for P0138: o2 sensor circuit bank 1, sensor 2. I quickly got a new post-cat o2 sensor, (Denso) installed it and reset the code. After a few miles of driving, P0138 came out. I reset the cel and it will still pop out after a few miles. What do you guys think might it be? I am thinking I'd replace the pre-cat o2 sensor, but wouldn't that show a different cel code? (or is P0138 for the two sensors). Thank you.
Could drop the cat and try cleaning the screen with a brush mostly clogged screen easy way to cut after the cat and use a coupler or reweld it Posted via the PriusChat mobile app.
What was the Denso part # you used for replacement? Here is the workup for DTCs P0136 P0137 P0138 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/2054m/cip0136.pdf
I used aftermarket cat 100. Off eBay and OEM sensors but it look like the screen was just clogged when I took it apart but I already ordered the cat Posted via the PriusChat mobile app.