My Bank 1 post cat oxygen sensor always reports high on the torque graphs no matter if I'm accelerating, idle, etc.

Things I've done: Swapped O2 sensors around. No changes. Replaced 02 sensor, No change. Removed o2 sensor, loss of signal. Since removing the 02 sensor results in a loss of signal I'm inclined to think that the 02 reading is correct. Even swapping the 02 sensors or replacing with new still results in the same readings...I'm thinking the 02 readings are correct.

So what does it mean? Looking at the below pictures you can see that bank 1 sensor 1 (pre cat) functions properly. Bank 2 sensor 2 (post cat) functions properly. But Bank 1 sensor 2 (post cat) is just steady at a high reading.

 

Are we supposed to guess exactly what you are working on? Or, what software you're using?

Is there some actual problem you're trying to solve or are you just on a fishing expedition?

 

The pictures show how Bank 1 sensor 2 (post cat) is at a steady voltage no matter if accelerating for idling. I've swapped it out several times with new or known working.

I need feedback on what the issue might be.

 

I would guess it's a wiring issue. The post cat sensors should be fairly steady but more like around .4v I think. But I'd it's not throwing a check engine light or making you fail emissions I wouldn't worry about it. The rear sensor don't effect how the truck runs in any way they just check the effectiveness of the cats for emissions compliance.

 

Perfect! I was worried it does effect the tuck. Thank you.

 

Sorry - I don't agree. I generally go along with @needsmoarturbo - but can't on this one.

The rear O2's don't effect how the truck runs (True). But the data from them still has a meaning. Not saying I know exactly what it is just yet, but it definitely deserves further investigation. SOMETHING is not right. The 'CATMON' continuous OBDII monitor routine monitor's cat efficiency and determines/drives trouble codes P0430. The routine monitors the 'ratio' between voltage switches between front and rear O2 sensors over periods of time. NO switching, - that is BELOW the factory switching spec (~60% to 75% depending on exhaust configuration), so you are not going to get a Cat Efficiency Code.

But there SHOULD be switching. When O2 voltage is HIGH - there is NO Oxygen present (or sensed). That should cause STFT to decline - migrate into LTFT - and ultimately cause a RICH code. That is effecting how the truck performs, though you might not be noticing it yet.

STFT readings - and some other Torque Pro stuff might be informative. Partially clogged CATS will lead to similar symptoms. Increased exhaust back pressure also effects performance.

JUST SAYING.