[Tutti57]

Was this data recorded after full warm up and at idle or cruising? under those conditions, the tears should be flat at around 700mV. Based on this data, the cats are shot. The front sensor is an a/f sensor and the rears are o2. A/f sensors report the opposite of o2 and are extremely fast, so you don't get oscillations like you'd expect to see with an O2. These o2 sensors shouldn't be oscillating like they are, so the convertors are bad. The only way to view the front sensors on torque is probably the equivalency ratio pid, which should show 1.0, but with this setup, you can't really compare fronts and rears because those a/f sensors will look very much like the b1s1 pids you have pulled up, but that data isn't right. It should be 2.2v. what you're seeing on the rear sensors has more to do with a lack of oxygen storage capacity than lazy sensor operation.

Something killed them, but it could have been damage from a long time ago that's just now gotten bad enough to throw a code. Fuel trims look good at the moment, but you'll find on Nissans fuel trim data is weird too. Notice how stft is fixed at -2.34v? It has something to do with what Nissan calls Alpha values, which are basically current total fuel trims, but you won't have that pid available on the torque app since it's enhanced oem data. Soo, unfortunately, this is going to be an expensive repair.

I commend you caring about data and not wanting to replace parts based on codes. If you like the torque app, I suggest you check out incardr pro. I have come to prefer it, and while it's not as customizable, it has some really cool features and does all module scans, which is unbelievable for $5.

 

[Tutti57]

Yeah, that info alone would be enough for me to call the cats.

 

[Tutti57]

You may not see any issues pulling it down though. I've replaced probably 6 converters in the last few months and none of them were obviously visually bad, but the data showed no stage capacity. Bad cats are not necessarily plugged. If it's oscillating after the rear is warmed up during a steady cruise or idle, the cats are bad.