Torque Pro help needed for 2014 Pathfinder

[gmcman]

I'm looking at a friends 2014 Pathfinder, has. P0420 Catalyst system efficiency below threshold.

I believe this was an older code, many months ago, but I'm not seeing any issues. Did not specify bank# and my Torque Pro app doesn't show any values for what I believe is the 3rd cat.

Also, I set up this screen to follow while I was driving, and the sensor 2 was showing the rapid change and sensor 1 was steady, like it was the inverse.

To verify, I disconnected the upstream sensor on bank 2, and the CEL showed sensor 1 bank 2 fault, so that still shows that sensor 1 is the upstream.

Here's the screenshots, trims look good, it drives good, but her mechanic says it needs a cat.

This is just pulling away, also, odd that both cats have the exact same temp.




This is steady driving.







I'm not buying that as of yet.

Are there any plugins I can use to see every O2 sensor?

Does the 3rd cat have a sensor?

All input appreciated.

​

 

[azswiss]

Does the 3rd cat have a sensor?

Checked for cats & O2 sensors on Rock Auto. Looking at the image of the rear cat and checking parts listings for the O2 sensors it appears that there are no sensors on the third (rear) cat . The two front cats have both upstream (O2B1S1, O2B2S1) and downstream (O2B1S2, O2B2S2) sensors.

The O2B1S1 & O2B2S1 readings seem odd as I would have expected them to be in the range of .1V-.9V.

 

[gmcman]

The O2B1S1 & O2B2S1 readings seem odd as I would have expected them to be in the range of .1V-.9V

That's what I'm confused about. The graphs are opposite of what they should be regarding sensor 1 and 2....other than the fact if the sensors are backwards in Torque, the upstream would be slightly lazy.

 

[gmcman]

Meant to add, these are my current options.

 

[azswiss]

I was struck by the fact that the scales are so different: .9V-8.5V for S1/Upstream & .1V-.9V for S2/Downstream. Piqued my curiosity so I did a little digging and I found something quite interesting.

What are Your OBDII O2 Sensor Voltage Readings?

Seems the upstream sensors may be a different kind of beast than we are used to on our GMT's. It is an Air/Fuel Sensor whereas the downstream sensor is a (standard) O2 sensor. Hence the different ranges.

Not sure how to interpret the results to see if that confirms the diagnosis on the cat.

Edit: Since the downstream sensor is an O2 sensor then we should be able to interpret its behavior the same way as on our GMT's. In that case the voltage swings are pretty frequent suggesting inefficient cats.

 

[gmcman]

the voltage swings are pretty frequent suggesting inefficient

That's where I'm stuck at. Going on the graphs, both cats have completely failed.

However there are no foul odors from the exhaust, no fuel odor, just hot normal exhaust.

I will shoot the temp with my IR gun but I want to say I'm not fully understanding this Nissan emissions setup.

Will give a shout to the dealer today and see what the deal is.

 

[Mooseman]

I will shoot the temp with my IR gun but I want to say I'm not fully understanding this Nissan emissions setup.

That should be pretty standard for any cat.