Looking for advice on P0420 code

[Hacker412]

I'm at a loss on what to do next to fix my daughter's 1997 Jeep TJ 2.5L. I keep getting a recurring P0420 code. I’ve already replaced the upstream O2 sensor with a new NGK 23179. During the process, the male portion of the O2 connector came apart, but I managed to get it back together.


I’m not confident in how to interpret the data stream. Could someone please take a look at the readings and help me figure out what’s going on?

Does it look like I need to replace the cat?

P02 data stream

Temp 210
RPM 2K
During data capture.

Thank you

 

[ItchyDong]

You probably need a

When you hold the rpm around 2000, that downstream sensor should hold rock steady. If it follows or tries to mirror the upstream sensor, the cat has failed.

 

[macleanflood]

A cheap temporary solution might be pulling the cat and checking for obstructions (and maybe knocking out said obstructions)...or measuring the temperature before, middle and after with a laser IR thermometer.

-Mac

 

[Hacker412]

A cheap temporary solution might be pulling the cat and checking for obstructions (and maybe knocking out said obstructions)...or measuring the temperature before, middle and after with a laser IR thermometer.

-Mac

Thank you! I will take the cat out and have a look at it. It might be the original, but it's kinda hard to tell.

 

[Hacker412]

You probably need a

When you hold the rpm around 2000, that downstream sensor should hold rock steady. If it follows or tries to mirror the upstream sensor, the cat has failed.

Just for a moment, I thought maybe I would take it to someone to replace the cat. After a $730.00 quote to replace only the catalytic converter, I realized two things. 1. I'm doing it myself. 2. I would be a millionaire if I could bill for my own repairs to this jeep. Thank you very much for your help!