I do have that OBDII Code reader, I've had it for 2 Years and didn't even know It read O2 Sensor codes, I Found out about it when You uploaded a screenshot of it in One of Your Post about the same Problem. I have been Using it since to monitor the O2 Sensor voltage. I didn't know the Versions matter, I don't know what My version is, Hopefully its written somewhere on it. But, isn't the v1.5 older than the v2 or v3? I would think the newer versions is what everybody would want...??
the newer ones arnt compatible with our older cars... I have a v2 or v2.1, I forget but it just never connects and talks to the APP / Car. the v1.5 works like magic.
o2 sensors are a funny thing. ill give you my 2 minute explanation.
they all have heaters, so on a cold car if you are reading live stats they will display 1.27V
the upstream (header) o'2s go to voltage soon, maybe 1-2 minutes. should read .6-.9V
the downstream (post cat) should ALWAYS read equal to or lower.
the downstream (post cat) takes 2-3 minutes to drop voltage and should be .2-.6v
now with that said, its like English, there is always an exception.
if your coasting downhill its not unheard of to see (for me) o2 reading all at .00 or .01v
neither side will be the same, if it is it wont last long,
this one the car was idling and you can see my 2x2 o2 is low voltage, that indicates an exhaust leak.
now if you have the car running for more then 5 minutes and you see 0v or 1.27v you have issues. 1.27v the heater is stuck on or the sensor line is broken.
if you have 0v its still a wiring issue.
I think the grey and white are the heater and black and one with line is sensor.. I cant find the pinout. maybe peva can help.
but live stats will push you in the right direction. trying to probe and look for a .4 or .1v difference, with a multimeter, lol, will be a royal pain in your.. you know what.