Hey guys, I have a P0420 and I believe that I can see if the o2 sensors reading with the right hardware and software. After research, it's likely that I need to replace the sensors but I want to make sure and I don't mind having the tools since I have a RX350 and in the market for an F. Also, I think the sensors lasting 196k miles is not too bad. FYI, I did have a leak in my mid-pipe that was causing this same code (+419 i think?), but went away when I replaced the mid-pipe, so I'm fairly certain it's not a leak. Thinking about it now, maybe there's a leak between the flanges.

What and where should I buy something to get the o2 sensor readings for my car and to use for diagnosis on my future Lexus/Toyotas, and why?

 

P0420 on this car is far more likely to be an exhaust leak than a bad O2 sensor. I would definitely check that first.

As for your question on Techstream, there are many vendors on eBay that sell the mini-VCI adapter cable used to hook the OBD port to your computer. There are two versions, the newer and more expensive version has drivers for modern 64 bit versions of Windows, while the cheaper ones only work with a 32 bit OS. Either requires a "professional diagnostic" level subscription to TIS (https://techinfo.lexus.com) to use the Techstream legally, which is the only kind of use ClubLexus forum rules permit us to discuss.

 

Cool. Thanks for the info. I'll crawl under the car this weekend and check for leaks.

 

You were right! I was missing a bolt on one of the flanges on the passenger side. Went to the dealer for a replacement and my car is slightly quieter and no more CEL.