Hemi 5.7 P0420/P0430

[acfortier]

I recently picked up a 2010 Jeep Commander with the 5.7 Hemi to DD. Mileage is around 173,000 (I've put on about 3-4k since I've bought it in late March).

 

I've been lately having P0420 and P0430 pop up here and there--but I can clear the code, and it does go away for some time. Also have a phantom P0456 coming up, but less often.

 

Trying to diagnose if I need new cats or not. I took a quick snapshot of the O2 voltage over a period of a few minutes last night, engine was at temp.

 

 

 

Pre-cat O2 sensors look fine, but the post-cat ones have some dips that might be somewhat concerning? I found this general reference chart that makes me believe that I do need new cats, although it's not as bad as their example?

 

[Ωhm]

Try swapping both O2 sensors. Make sure problem doesn't follow the sensor. Maybe make jumper wires, PRE to POST and visa versa.

[acfortier]

Just now, Ωhm said:

Try swapping both O2 sensors. Make sure problem doesn't follow the sensor. Maybe make jumper wires, PRE to POST and visa versa.

I suppose I could, but it really looks like both sensors are having issues? Bottom is bank 1, top is bank 2.

[Ωhm]

B1 & B2. I understand now.