JK Exhaust system advice

JeepinRay

New member
Need a bit of advice ... have check engine code P0420 - Catalyst Efficiency (bank 1). 2008 JKUR and currently at 82,000 miles so just out of warranty.

I've had this code for about 8 months and don't notice any performance issues. Should I just ignore it?

If in fact I need to replace the cat system are there alternatives to just replacing with OE part that could be of equal or better quality and maybe improve performance at a similar price point?

What are some proper diagnostic procedures that I should be aware of if I take this to a local exhaust shop? Like could it be just a sensor bad and if so should a good shop know how to test for that vs. just selling me a new system?

Fairly new to the forum here and am enjoying it greatly. Appreciate any advice and insight.
 
Last edited:

JK_Dave

Caught the Bug
If you're required to pass an emissions test for your inspection, this may come up. I'm sure any inspection station could confirm that for you.

Not sure there's any performance cat out there specifically made for the Wrangler, but I could be wrong. If you have to replace it, I'd just cut one off a junkyard exhaust and weld it onto yours.
 

wayoflife

Administrator
Staff member
Need a bit of advice ... have check engine code P0420 - Catalyst Efficiency (bank 1). 2008 JKUR and currently at 82,000 miles so just out of warranty.

I've had this code for about 8 months and don't notice any performance issues. Should I just ignore it?

If in fact I need to replace the cat system are there alternatives to just replacing with OE part that could be of equal or better quality and maybe improve performance at a similar price point?

What are some proper diagnostic procedures that I should be aware of if I take this to a local exhaust shop? Like could it be just a sensor bad and if so should a good shop know how to test for that vs. just selling me a new system?

Fairly new to the forum here and am enjoying it greatly. Appreciate any advice and insight.

Take your Jeep to the dealership or an exhaust shop and have them do a pressure test. Could be you just have a leak in your exhaust system and now your O2 sensor is giving a bad reading.
 
Unfortunately, your best diagnostics will come from a dealer. A properly operating catalytic converter has little to know performance loses to begin with so their really is no need to look for a "performance" one. In most cases a catalytic converter doesn't just go bad, they are usually killed due to something else being wrong with the engine. Things like burning coolant are quick cat killers. It is possible your cat is working and the post cat O2 sensor is reading incorrectly but this is unlikely. O2 sensors usually fail either open or shorted, not somewhere in between.

I thought the federal mandated warranty on emission components was stretched to 100k. If this is the case it would still be under warranty.

In any case.... If I were were you I would be having a full diagnostics done on the engine. My guess is that there will be more going on than just a bad cat.

Out of curiosity.... is your exhaust rusty on the pre cat side? And leaks?
 

CerOf

Member
I thought the federal mandated warranty on emission components was stretched to 100k. If this is the case it would still be under warranty.

I thought it was 8yr/80,000miles?
Looked at my manual and only 8/80k


Sent from a a few tin cans and some string.
 
Last edited:

JeepinRay

New member
Take your Jeep to the dealership or an exhaust shop and have them do a pressure test. Could be you just have a leak in your exhaust system and now your O2 sensor is giving a bad reading.



Thanks for all the insight. Like this idea and think I'll do that. Sure would be nice to find a solution that doesn't involve spending quite so much money. Dealership now tells me the federal warranty is 8 yrs / 80k ... not to get into my whole sob story with why I didn't get this fixed before 80k ... but it involves my ignorance of the federal waranty and the dealer telling me I had no more warranty on the Jeep way back at 60k ... anyways, that's come and gone now. No exceptional rust and no visible leaks that I can tell. Jeep runs great besides a slight ping sometimes at about 2000 rpms. Don't think that it's related. If it's not just a leak I'll probably ignore the code for a while and just fix it sometime down the road. Need to spend some money on that new front bumper and rock sliders soon :clap2:

Gotta say it's good to have such a responsive group here. Thanks :thumb:
 

wayoflife

Administrator
Staff member
Well, if it is just a leak somewhere, the fix should be pretty easy and cheap. An exhaust shop can probably take care of it for about $100.
 

JeepinRay

New member
Well, if it is just a leak somewhere, the fix should be pretty easy and cheap. An exhaust shop can probably take care of it for about $100.

One of the things I forgot to mention was that when I took it in to my local exhaust shop they pulled the code and it also showed a code "misfire on cylinder 3". They mentioned that this could cause the 0420 code and recommended I change coil, plugs and wires. I did that but 0420 came back on next day. I'll have them check for leaks and hope that's the prob.
 
Top Bottom