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Discussion Starter #1
I can't say for sure if this will apply to 'all' issues with P0432 since cats do go bad, but I will share my adventure to date and what I have discovered what caused mine... I think.

I first installed a 2" BB last year around May-June 2011 time frame with no CEL's at all...

Got vibes and installed a 1" TCD... didn't like the lost clearance and swapped it with a 1" MML.... got CEL and code P0432 for Bank 2 Cat Efficiency below threshold...hmmm...

Noticed on scanner the Bank 2 Post -cat 02 sensor was not reading correctly and swapped it for a new one ( Bosch ) Cleared codes and never saw the CEL

I even install a Dynamax Cat Back with no CEL to worry about....I thought I was good to go... then....

I installed a TT from UCF which raised my skid 2.5" using the stock tranny mount. The exhaust was pushed up with the TT, but didn't think anything of it. about a week after the install, I went offroad and the P0432 came back. I was PISSED!!!

At that time I was contemplating swapping the downpipe cats myself with a thread I found from a WF member that did it... seemed easy enough, but I held off a bit until I got my LoPro mount from UCF and install it to see where everything was going to sit after the install.

I noticed some side to side play on the downpipe when wiggled with everything hooked up... seemed a bit loose... didn't think much of it right then.

As I am disassembling the skid and tranny mounts to do the mods for the Lo Pro, I notice how far the exhaust dropped when I remove all the components. Got me to start looking a the exhaust a little more clearly with the junk out of the way.

I started wiggling the exhaust from the third Cat now since the only three points holding it now was the manifold bolts, and the hanger behind the muffler and one at the tailpipe.

I got a LOT of side to side play like it was just 'hanging'. Inspecting the manifold flanges I noticed that as it swings side to side, the flanges moved a bit and I can see movement in the flange bolts. WIERD!!!! I had NO EXHAUST LEAK AT ALL that was audible.... nothing can be heard.

I decided to spray down the bolts and loosen them to find they weren't even really tight... just snug.

I continued to install the the LoPro mount which actually drops the t-case ~1" closer to the skid, essentially causing less pressure on the exhaust as well. After the install and adjustments, I tightened the exhaust manifold flange bolts. Exhaust was much more solid now as I couldn't wiggle the downpipe as I could before. Cool...

BTW... I NEVER DISCONNECTED THE BATTERY....

I started up the Jeep and I have no CEL's at all. There is no difference in sound ( leak ) as I couldn't here one before... but the CEL is gone.

It's only been a couple of days.. but no sign of it yet.

so... why did I post this? I got to thinking....

When did your P0432 show up?

Have done any mods to alter stock position of exhaust?
-MML
-TCD
-TT

If so.... you may want to check your manifold flange bolts or drop the down pipe and clean the connection flanges.... this 'could be' your solution.

You have to remember.... even though the exhaust bolts to the manifold, it hangs from hanger attached to the frame at a few points... moving the motor,trans and t-case in whatever direction puts stress on the exhaust which can move the flange connections just enough to cause an issue if they are loose.

Like I said... this is my insight to what I found on my Jeep.... posting in hopes to possibly helping another kill the dreaded P0432 code that could my just be as easy as a loose/relocated flange connection that has been in one position for so long and moved, causing an unnoticeable leak to throw off the 02's.
 

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Hmmmm. interesting read...I have done just about all of those mods to my rubi this year and have had a PO431 code that seems to come and go....I will check all of the things underneath that you mentioned...thank you for the info
 

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Wow I'm going to check that out. My '04 has a nearly permanent P0432 which the PO (Gerald Lee) had. He said he swapped the 02 sensors which didn't help which apparently left one of the two pre-cats as bad. I even have the two pre-cats in route to me to weld into place. I'll check the exhaust first as you suggest, you will have made me a happy man if I don't have to replace the bad cat on the header.
 

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Discussion Starter #4
Jerry,

I was going down that same route.... I just held off buying the mini-cats until the LoPro was in to ensure I wouldn't be moving the exhaust anymore.... glad I waited.

Hope you both find resolve with what I have discovered with mine....
 

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I almost forgot to say have a flat skidplate which has shoved the exhaust system up higher which makes me even more suspicious of it having something to do with it.
 

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Enjoyed the read.......so far so good........have done all but the TT looking for one that doesn't "require" an SYE (understand that it may be needed anyway) does the UCF and LoPro get you by without an SYE?
 

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Discussion Starter #7
Enjoyed the read.......so far so good........have done all but the TT looking for one that doesn't "require" an SYE (understand that it may be needed anyway) does the UCF and LoPro get you by without an SYE?
If you have a lift already... you will need the the SYE for sure.....

You have to remember.... just a TT is putting your driveline angles as if you are running a 2" lift or better if you are stock ( depending on the skid you get ).... add a 4" lift and it's like a 6.5" lifts when it comes to driveline angles.

If you are seriously thinking of a TT and/or SYE... I highly suggest a Megashort SYE to help with driveline angles.

Ensure you do your research on all that is involved with doing a TT correctly.... not cheap.


Now back to the post.... ;)
 

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You can add me to the TT & MML crowd that has CEL for P0432 (or maybe P0431) code that I cannot get rid of. The rigs runs flawlessly and gets good gas mileage so haven't pursued it too much.

I'll definitely be keeping a watch on this thread.

Vince
 

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Discussion Starter #9
You can add me to the TT & MML crowd that has CEL for P0432 (or maybe P0431) code that I cannot get rid of. The rigs runs flawlessly and gets good gas mileage so haven't pursued it too much.

I'll definitely be keeping a watch on this thread.

Vince
best to check your rig .... why wait for others? This doesn't cost a thing... and it's only time put to good use checking out your junk... nothing lost there....

It will be interesting to see who all has been affected by this and where it goes ....
 

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My exhaust near the mini cats swings side-to-side a little. And my jeep threw the P0432 code, too. I can't hear an exhaust leak, but I'm going to tightened up those flange bolts and see if that clears the code. And if it doesn't clear the code, well, they needed to be tightened up anyway.
 

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I just got done replacing all 3 cats after mine threw a p0432. The cat had actually broken off and fallen down into the pipe and clogged it up.

image-745335968.jpg
 

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Alas! A one year old thread is brought back to life!
 

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Alas! A one year old thread is brought back to life!
Yes! Thank the gods for the search function and old threads! (that's what they're there for, right?) If only I would have found this one a few hours earlier...ya know, before I removed my exhaust and destroyed one of the pre-cats out of frustration and childish curiosity.
 

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Any updates on nay of these? Ordering pre cat and o2's tomorrow. Would love to save $350
You can check the function of your cats with a digital temp gauge, the cat creates heat if its working properly, the upstream end of your cat should be cooler than the downstream end of the cat. If both ends are the same more than likely the cat has blown out its guts. Thats what mine did, I bought the bosal cat setup from rock auto and replaced all 3. No more codes, mileage is up to 18 mpg and it runs a lot better than it has since I have owned it.
 

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I will double check it in the morning. My uncle owns a muffler shop and he already checked it, but you never know if something quirky could be possible I guess. Some arched metal cloaks would be a lot more fun to install than a cat, lol.
 
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