Was setting up gauges and noticed one of my precat 02s is showing 0V. Failed? (3 Viewers)

[Obioban]

Was setting up my phone to read trans temps for a fluid flush/leveling, and I noticed that one of my pre cat 02 sensors is showing 0V. Would I be correct in assuming it's failed?

Really surprised that didn't throw a CEL, if so....

Also, any way to know if my truck uses the wideband or narrowband 02s? From what I'm reading, the 2UZ used both. My truck is a 2006, if it matters.

 

[Obioban]

So, reading further-- 0-1V means narrowband? And, 4 wires (which it has) means narrow band. But, from what I read, 2006 should have the wideband?

Also, is this a place where OEM Denso is just as good as stock? Or, should I pony up for OE Lexus/Toyota?

 

[OEMGUY0720]

Possible but not certain yet. How long has the engine been running when you took this snip? Best is 10 minutes after it had reach minimum 187°F coolant temps aka optimal engine operating temps. Once you hit that mark, rev it to 2,000rpm and hold it there and see if that reading will change, it should. If it doesn’t it likely has failed.

An example:

Sensor 1 is upstream, Sensor 2 is downstream (by the catalytic converter).