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P0432 Code - 2001 XJ 4.0L – Auto – AW4/NP231 – 259K miles


NAXJA Forum User
Santa Rosa, ca
Hi all.

I am new to the forums (and to mechanical & Cherokees in general) and have a diagnostic question/advice request regarding my XJ:

’01 XJ Classic – 4.0L – Auto – AW4/NP231 – 259K miles. I bought it back in June ’22 and have put about 200 miles on the car since I bought it. (Note - Seller owned 3 jeeps (this, a YJ, and a newer 2017+ Cherokee) and this was his daughter’s car. Seemed to be a competent mechanic and he replaced the 0331-cylinder head, water pump, timing belt, alternator, in the prior 12 months with receipts. The battery was 5 years old, and after about 2 weeks of owning it I replaced the battery.

During the few times I drove it, I noticed it seemed to be less powerful than my other XJ (97 XJ w/ 270K) and the lifters were sticking. I bought some Seafoam and was going to treat it. I drove on about a 100-mile round trip to pick up some parts from a crashed XJ (of course) and on the way home the CEL came on.

1) P0432 – Catalyst Efficiency Fault (Bank 2)).
2) P1694 No Engine Bus messages – this code has auto cleared and is no longer on, but the P0432 remains (could this be an ECU issue?)

I have posted the photos of the code reader output below. I suppose I could start by replacing the O2 bungs, but I have read through several folks who have indicated that because this is an ’01 and has both the pre-cats/post cat setup, that I may need to replace the entirety of the cat. Not super exciting as that’s going to be more than $1,000 from what I can tell, even at rock auto (Yea, I’m in California so that’s why the cost).

In addition to the above, I wanted to make sure that given the previously-described lifter issue, that there wasn’t some incorrect fuel/mixture that would cause more excessive damage. The vehicle was just smogged in June, so I don’t technically have to smog it until May 2024 (this is also surprising to me that it passed in June, less than 200 miles ago, and now cat is bad?).
I posted the OBD reader output as I thought perhaps this might be meaningful to some of the more experienced folks. If folks recommend replacing parts, I’d appreciate advice on which parts to use. Happy to spend a little more to get this done correctly (NGK?). I’m also curious if my fuel trim looks correct? Don’t think (?) it’s too far off, but open to any thoughts, opinions, perspectives. Thanks for your time.


Threads I’ve read: