Again with the CEL! (P0421)

[astjp2]

I will stick with the $89 ebay manifold and dump the cats...when mine go out.

 

[BoldlyGoing]

I will stick with the $89 ebay manifold and dump the cats...when mine go out.

I’d love to... sadly metro Atlanta requires emissions testing. So that takes that option off the table.

For future googlers- here’s what mine looked like when I pulled them, and the chunks of catalyst afterward.

 

[badlieutenant]

Don't you wish you lived where I live? No emissions, no inspections... nothing.

Now you'll understand why I'm gutting ALL of my emissions and disabling the systems via the PCM.

You have NGK sensors, right?

If so, it very well could be your cats. Those pre-cats seem to start getting iffy around 100k miles. You can't just buy one pre-cat to my knowledge, but a full replacement pre-cat downpipe is only around $300.

Chris, please elaborate on what exactly you’re going to cut and how to disable the systems via the PCM.

I’ve been throwing P0421 for a long time. I actually look apart my instrument cluster and put black tape over the CEL LED and reassembled it. I also put some tape over the airbag light too since I disabled my airbags (my 10 year old rides in the front and the 06 doesn’t have an airbag sensor or disabler).

I’d love to remove all that crap and disable it within PCM.

HOW YOU DO THAT?

 

[Boinked]

Chris, please elaborate on what exactly you’re going to cut and how to disable the systems via the PCM.

I’ve been throwing P0421 for a long time. I actually look apart my instrument cluster and put black tape over the CEL LED and reassembled it. I also put some tape over the airbag light too since I disabled my airbags (my 10 year old rides in the front and the 06 doesn’t have an airbag sensor or disabler).

I’d love to remove all that crap and disable it within PCM.

HOW YOU DO THAT?

He posted it here

https://wranglertjforum.com/threads...005-2006-jeep-wrangler-tjs.16403/#post-266276

 

[badlieutenant]

He posted it here

https://wranglertjforum.com/threads...005-2006-jeep-wrangler-tjs.16403/#post-266276

I need that... and I need to remove those stupid cats.

Why remove the evap stuff? What’s that do?

 

[Chris]

Chris, please elaborate on what exactly you’re going to cut and how to disable the systems via the PCM.

I’ve been throwing P0421 for a long time. I actually look apart my instrument cluster and put black tape over the CEL LED and reassembled it. I also put some tape over the airbag light too since I disabled my airbags (my 10 year old rides in the front and the 06 doesn’t have an airbag sensor or disabler).

I’d love to remove all that crap and disable it within PCM.

HOW YOU DO THAT?

See here: HPTuner MPVI2 & VCM Suite Review: 100% Full PCM Access For 2005-2006 Jeep Wrangler TJs

 

[BoldlyGoing]

Chris, please elaborate on what exactly you’re going to cut and how to disable the systems via the PCM.

I’ve been throwing P0421 for a long time. I actually look apart my instrument cluster and put black tape over the CEL LED and reassembled it. I also put some tape over the airbag light too since I disabled my airbags (my 10 year old rides in the front and the 06 doesn’t have an airbag sensor or disabler).

I’d love to remove all that crap and disable it within PCM.

HOW YOU DO THAT?

Just a heads up- if you haven’t already checked, my front cat had completely disintegrated and was blocking the main cat. It was robbing me of power.

Worth a look. Annoyingly, there is no way to remove the cat without hacking the exhaust apart between the pre and main cats.

 

[badlieutenant]

Just a heads up- if you haven’t already checked, my front cat had completely disintegrated and was blocking the main cat. It was robbing me of power.

Worth a look. Annoyingly, there is no way to remove the cat without hacking the exhaust apart between the pre and main cats.

I suppose a muffler shop would be able to cut off the pre and main cats and weld on new ones?

It’s just ridiculous that there are a total of four.

 

[BoldlyGoing]

I suppose a muffler shop would be able to cut off the pre and main cats and weld on new ones?

It’s just ridiculous that there are a total of four.

There are 3 total. 2 mini cats up front and 1 large one at the rear.

If you don’t care about the light on the dash and don’t have emissions testing, you could just cut it, shake out/punch out the cats and slap a butt clamp on it.

I have heard (and can speak from experience) that it does affect gas mileage. My understanding is that the engine/computer is tuned to run best with the cats in place, but I’m not knowledgeable enough to say whether that’s the case.

 

[badlieutenant]

There are 3 total. 2 mini cats up front and 1 large one at the rear.

If you don’t care about the light on the dash and don’t have emissions testing, you could just cut it, shake out/punch out the cats and slap a butt clamp on it.

I have heard (and can speak from experience) that it does affect gas mileage. My understanding is that the engine/computer is tuned to run best with the cats in place, but I’m not knowledgeable enough to say whether that’s the case.

Maybe I’m confusing the four o2 sensors then? I thought 2006’s had 2 pre and 2 rear.

Really, I wouldn’t mind replacing them with an aftermarket solution that’s better than the crappy ones it came with.

I wish the previous owner had just taken care of it at the dealership under warranty but he didn’t... he instead took it to a regular mechanic that just replaced the o2 sensors with who knows what brand and never fixed the issue. It would have been covered under the emissions warranty when he had it.

 

[KCsTJ]

My pre cats went south, "as scheduled" at 104k.
I had to replace them to satisfy emissions.
I got the Evan Fischer exhaust with 2 precats.
Solved my 0421 and other 02 sensor codes.