2001 4.0, P0432

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N8N_99xj

NAXJA Forum User
NAXJA Member
Location
Curtis Bay, MD
I finally got the emissions notice for my "new" XJ this morning, and the emissions station is literally on my way to work and about half a mile from Costco so I went and got gas and then went to get my emissions test. Welp, wasn't as easy as I thought. Apparently my MIL burned out sometime since I got this thing, and I also have a P0432 code that I never knew about because the MIL doesn't light up. I guess I just never really noticed it wasn't bulb checking anymore.

Are all the idiot light bulbs the same? e.g. can I switch it for a different one like "check gauges" and then get a new one? Or does someone have a part number for them?

On googling, it appears the code is likely the little mini cats. Well, that would explain it not heat soaking... Anything else it could be besides an O2 sensor? Anyone know what book time is for replacing those so I know what I'm in for? I am not going to be able to do it myself, I don't even have a driveway anymore :/ I'm sure this won't be cheap either as I believe this one just like my last one has 50 state emissions.

Stupid thing is I already had the dash apart once to fix the tilt steering, guess I get to do it again now...

I have stuff I *want* to fix on this silly thing but I keep getting caught up in stuff I *have* to fix...

thanks for any advice
 
A real time scanner might help identify the bank/cat by their readings.
 
yeah I'm looking for mine now, it's just a cheap HF one though. I may have to go get another one because if I can get the readiness flags set it runs great. I moved a couple months ago and nothing is easy to find unfortunately
 
BTW, my 2000 used pc74 leds in the cluster. I don't recall if it also used any 194's.
 
So, I found my scanner today. It wasn't long after I got home from work so I went ahead and scanned it.

The nice VEIP lady wasn't lying to me, I had a MIL on (but it's not actually on; I don't have the bulbs yet because the NAPA on my way home didn't have them, they should have them tomorrow) and I do have a P0432 code. That's "Main Catalyst Efficiency Below Threshold (Bank 2)" No other stored or pending codes. I did clear it; we will see if it comes back before the flags set. Gotta at a minimum fix the MIL anyway.

I'm assuming what you wanted me to look at was the O2 sensors, looks like I have 4, I don't remember the whole acronyms but it appeared to be one upstream and downstream Bank 1, and one upstream and downstream Bank 2. Values were up and down between 0.3 and 0.8ish which I believe is good, but they appeared to be about the same frequency - so does that mean that the little cats really are dead? (this is idling in front of the house.) I'm also assuming from my experiences with BMWs that Bank 1 is 1-2-3 and Bank 2 is 4-5-6 so this leads me to believe that step 1 is to get two new sensors for Bank 2 (which I'm guessing won't do anything) and then if that doesn't fix it the two smaller cats need to be replaced. Correct? My scanner is a cheap POS (Cen-Tech AKA Hazard Fraught, I bought it before I bought my previous Heep as I was looking at a lot of POSs and I wanted to check the readiness flags - and this was before historic tags were an option although I still don't like that one) so I can't throw all four up as if on a scope which might yield more insight.

also, yikes. https://www.magnaflow.com/products/...carb-compliant-direct-fit-catalytic-converter

Finally, I think I have another thing that needs to be replaced. I already wanted to replace the fan clutch and alternator and haven't done it because it's just been so consistently, brutally hot here... well right now it's 65 and rainy (which is why I still haven't replaced those items - it's been raining for two weeks straight, every damn day), and the thing is now not running too hot as it was before but too cool. ECT was only 82C leading me to believe that it probably doesn't have a proper 92C thermostat in it. (possibly PO installed a cooler one instead of replacing the fan clutch because he also didn't like it creeping over 210F?)

Dammit Jeep stop being so needy! And what are the odds that my physical MIL failed right before it actually threw a code? That's just being difficult.

Anyway, please tell me if I'm off base on any of the above.
 
Also: I've been taking surface streets to work because it's less stressful. Is there any chance that if I start just hammering it on the Interstate instead, the old Italian tuneup could get a little more life out of these cats, at least long enough to set the flags and get me another two years?
 
Well, I'm beginning to be cautiously optimistic - I cleared the codes two days ago and everything is good except the CAT readiness flag isn't set yet. I have no stored or pending codes.

I did take I-97 to work this morning and kept my boot in it a little. I don't know if that helped or not.

I'm having a heck of a time finding PC74s however. NAPA didn't get my order to my store today and there was no way I was going to get to the next closest one before they closed. Nobody else has them apparently. I'm thinking of just ordering these


and using regular 74 bulbs which at least VatoZone had (I stopped on the way home just in case. My local Pep Boys is now apparently a service center only now so no parts???) That should work right? That way if I get stupid and go full LED I can do that too.

Last time I had an issue with NAPA my parts just never came in so I assume that's what is happening here (I ordered something like 10 VW wheel bolts because they were all in various stages of rounded, and apparently every store in the area showed 2-3 in stock but when they went to send them to my local store it was an inventory error)

I do need to at least get the MIL working and the CAT readiness flag set. I've been driving around with the scanner waiting to see it change :) (I did the same thing with my 335i the last go around but you know what the MIL hasn't come back since. Now that I said that you know what's going to happen.) I am going to ask but I do not believe that MD allows you to have any flags not set and in my case since I had a cat efficiency code they'd probably look at me disapprovingly if that flag isn't set.

Good news is the VEIP station is halfway between work and home so soon as that flag sets you know what I'm gonna do!
 
To steal a phrase, it was a good day.

I did another hot run down I-97 this morning just in case... I have no idea if it helps or not but an Italian tuneup never did any harm.

My bulbs (I ordered two, just in case) actually did come in at NAPA although I already ordered the Chinese holders if I need any more. Just finished buttoning the dash back up as it got dark; I now have a functional MIL and *all 7 readiness flags are set*.

You best believe I'm going to be at the VEIP station at 7:01 tomorrow before anything else breaks.
 
Well, guess what came on while going to lunch today, 3rd drive cycle since passing emissions...

But at least now I have two years to deal with it :)

Is there any point in replacing O2 sensor(s) or should I just go straight to cats?

Recommendation for best parts would be appreciated. Am thinking of getting the Magnaflow cats as they're not that much more expensive than Walker. What about O2 sensors? OEM are apparently NLA and I do not have any idea who makes good ones and who makes crappy ones.

This isn't going to happen for a while though as I'm still saving as much as I can to get my VW out of the shop - the driver's seatbelt broke and then the immobilizer died within two weeks of each other. @#@#$% cars.
 
OK, now I'm right back where I started.

Recap: 2001 4.0, Cali emissions (I believe they all were though, weren't they?)

went to get my IM last Tuesday and it turns out my MIL wasn't working and I was also showing a P0432 "Main Catalyst Efficiency Below Threshold (Bank 2)". I just never noticed that at some point it stopped bulb checking apparently.

Cleared the code, did a run down I-97 at what a non-Jeep owner would think was a ludicrous rate of speed for an XJ two days in a row. Ordered two PC74s from NAPA, they came in Friday before I left work so I hurried up and replaced the bulb Friday night when I found the CAT readiness flag was set. Hit the VEIP station early Saturday morning, got my IM, all good, right?

Monday lunchtime, MIL comes back on again, same code. But not long after, the MIL starts going off, then on, then off, then on, etc. - way faster than would be expected if the code was clearing and then resetting. Now it's more or less off, but when I hook up the scanner it says MIL is on.

So now I have two problems. I suppose it's possible that I have a bad *new* bulb, but it seems unlikely after only a couple days and a couple short trips. Am guessing bad connections behind the IP? Or do I need to clean at the PCM too? I'm not sure if the MIL is 12V from the PCM or if it is driven by electronics in the cluster. I do know that the MIL would come on when my old one (very similar 2000) said "NO BUS" and the gauges died but whacking the knee bar below the cluster on the right of the steering column always fixed it so I never actually did a proper repair.

Any ideas would be greatly appreciated. I'm kinda frustrated ATM because I have other things I want to fix as well.

My roads really are garbage around here; should I go to LEDs now to forestall vibration/impact related failures? I have the holders so I don't need PC74s I could use regular 74s; any recommendations appreciated.
 
I recommend NTK sensors.

Although you should really watch b2s1 and b2s2 at the same time. While loaded in drive at 1500rpm.

You'll want to take it on a moderate highway run at 55 or so for like 10 min before hand. The b2s1 should switch between .2 to .8v relatively quickly. B2s2 should hover around .6v and waver a little on a properly operating system.

If B2s2 is switching similar to b2s1, the cat is done and needs replacing. 😪
 
Thanks for the reply. I haven't looked at the data exactly as you say, but idling with the engine warm the S1 and S2 seem to be switching at about the same rate. As I say my scanner is pretty crap though... and I will have to try it while driving and see what I get.

I'm assuming if I replace the cats I should just plan on replacing both downstream O2 sensors, yes? Or is there a chance of successfully reusing the original ones?
 
Wasn't able to hold a steady 55 but at 65 both rear sensors are swinging, I saw as low as 0.1 and high as 0.8. am guessing it's cat time, Heep has 209k and supposedly a replacement engine (but I doubt cats)
 
If you can get them out, they appear to be working.

Make sure that the engine is tuned up well. Catalyst failure is caused mostly by poor engine combustion. Make sure the plugs are in good shape. And I'd consider getting the injectors cleaned.
 
four_shot said:
If you can get them out, they appear to be working.

Make sure that the engine is tuned up well. Catalyst failure is caused mostly by poor engine combustion. Make sure the plugs are in good shape. And I'd consider getting the injectors cleaned.
Click to expand...
Yeah plugs definitely as the waste spark ones only last 25-30k. I'm super busy fixing shit even though this is the nicest XJ I've ever owned.
 
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