Hey folks! Any help would be appreciated! 2001 es300 up for inspection in NJ. Check engine light on with error code P1155. I changed sensor in Bank 2 sensor 1. Check engine light stayed off 3 days. Then check engine light comes back on with a new code P0420. This has me stumped. Some guys say catalytic converter bad, some says 02 sensors bad???? There are some expensive parts. ANY HELP WOULD ME MUCH GRATEFUL!!


Thanks

 

i had the same p0420 code. it got resolved after replacing the Bank 1 sensor 1.oxygen sensor. The connector is beneath the driver seat. Always use oem toyota sensor.

 

Of course you will be told the typical "bad cat" or "bad 02" as that's the go to response from techs these days. There are likely 40 threads asking the same question with the same code. Try the search feature and see if you can come up with a good thread. I'm sure some here have had the exact problem you're dealing with now.