Sooooo, got an O2 downstream sensor low voltage and also a no voltage code on my bank 2 side. Replaced it with both a cheap Chinese and then a Denso, and both are still showing low voltage. There’s no air leaks, fuel trim is good, nothing wrong with wiring. Only thing that I’m unsure about is that there’s what is possibly an extension on the converter attached (rusted on now) to where the sensor goes, which effectively keeps the sensor out of the cat and away from the hole by about an inch or so. I am guessing that this is one of those illegal attempts to get a lower reading to pass emissions that unscrupulous people put in to bypass doing any real work or to save money fixing expensive problems. But that shouldn’t produce a lower voltage should it? Or does it do just that? And so far no new codes but need to drive it some more. Attached below is my reply with a pic and another pic in a link of the O2 downstream sensors for Banks 1 and 2 so you can see the voltages.
