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OBD Catalyst monitor not clearing

 
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Old 07-02-2017, 06:58 PM
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Default OBD Catalyst monitor not clearing

I have the same problem that was recently discussed on:

https://www.jaguarforums.com/forum/x...-ready-184319/

Car is a 2000 XJ8L. Battery was replaced in Feb. Driven 2K+ miles since then, at all speeds and driving conditions. Catalyst monitor will still not finish its test and clear.

I also live in CA, and this incomplete means a downcheck during smog testing (if it was a 1999, one incomplete monitor doesn't mean a downcheck, but for 2000 it does...).

I have run what I think is the right drive cycle for this monitor test, multiple times:

Warm engine up.
Place in park, rev engine to 2500 RPM for 5 minutes.
Drive around, over 1500 RPM and over 10 mph.

I have also been driving it around this weekend forcing (auto) trans into low gears to really rev the engine (up to 3000-4500 RPM). Nothing seems to work.

On my OBD reader, when hitting high revs, I can see the test attempt to run (icon changes from blinking red to "communicating with car" for 5-10 sec, but then always returns to blinking red). It's trying, but it just can't clear the test. All other monitors are in the green.

Otherwise, the car is running fine, but I REALLY have to deal with this to get it smogged.

So -- any advice for different drive cycles to try? Or anything? Please help!

The only other answer seems to be to replace the engine computer. If this is what I will have to do, I have a few questions:

Is the 2000 XJ8 unit called the ECM or the ECU? Don't want to buy the wrong one...

I've seen new ones offered for upwards of $1700, but used ones for around $150-200. Anyone got a supplier for a used one that can be trusted?

I realize if I do this, I've got to go to a mechanic to "introduce" the chip to all the other computers in the car (using WDS? something like that...), so I won't be attempting the repair myself.

Any and all advice appreciated -- thanks in advance!
 
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Old 07-02-2017, 07:32 PM
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Have you looked in The Marketplace at the top of the forum for members parting out their cars?
What kind and how old of a OBD scanner are you using and model? Have you tried another OBD, say maybe going to O'Reilly's and/or Autozone? ...do you have a neighbor who has one?
 
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Old 07-02-2017, 08:11 PM
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Highhorse -

Thanks, I will check the Marketplace.

Scan tool is FixAssist 3130e. Bought it last year.

I don't think the problem is with the scanner, though. I talked to a local sports car mechanic (who knows Jags) and he's got a $10,000 scanner he uses. He told me it wasn't even worth me bringing the car in, though, since when the test doesn't complete, there's simply no data for it to read, no matter how good the scanner...
 
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Old 07-02-2017, 09:01 PM
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Are you sure your upstream and downstream O2 sensors are working?
Should be able to see them functioning on your reader, together with the fuel trims for short and long term.
 
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Old 07-02-2017, 09:28 PM
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ericjansen -

I will check the readings, thanks. But one of the other monitor tests is "O2", which (I believe) tests the two monitors indpenedently. So if it was an O2 sensor fault, wouldn't that monitor also either not clear the O2 monitor or throw a MIL fault code?
 
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Old 07-02-2017, 10:14 PM
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ericjansen [2] -

OK, went and tried again with the 2500 RPM test (failed to clear, again).

But while I was waiting, checked the other readings. All O2 sensors seem to be giving valid data. I'm no expert at this, so didn't really know what the numbers were actually telling me, but they were giving data as the car ran...

Anyway, thanks for the suggestion. I am learning more about what the reader can do, that's for sure!
 
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Old 07-03-2017, 02:33 AM
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It's not at all likely to be the ECM (or any other computer module). A fault elsewhere almost for sure.

You may be in the Catch-22 in that other thread. Try its ideas or find a really expert jag tech (an indy, most likely).

The other thread seems to have died with various questions unanswered so further ideas may be tough to get if that's what happens here too.
 

Last edited by JagV8; 07-03-2017 at 02:39 AM.
  #8  
Old 08-20-2017, 12:24 AM
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Default Problem RESOLVED!!!

I've seen a lot of these OBD monitor threads, but most of the trickle off with no resolution. So even though it's a couple months later, wanted to close this thread off on a positive note, just in case someone searches on the subject somewhere down the road.

Here was my experience: read all the "drive cycle" info I could, and tried all of them over and over again for a number of weeks. Catalyst monitor still would not clear.

In desperation, called up TWO Jag dealerships, finally got to talk to a real mechanic and both honestly told me the same thing: "Don't even bother bringing it in, we're just going to run the same drive cycles you are. When the monitor doesn't clear, it GIVES NO DATA, so even our sophisticated diagnostic equipment is no better than your $150 OBDII reader. Both will have the same info -- namely, none. Just keep trying the drive cycles, it's the only thing you can do."

At least they were honest, gotta give them that.

Went back to the guy I bought the car from, a VERY small-time used car dealer (but honest and trustworthy), and asked where he sent his cars to be smogged. Went to them, and they advised trying a fuel additive.

Well, I wasn't that enthused, especially when I found out one bottle cost $30. But I had nothing else to try, so I bought one.

Followed the directions on the Cata-Clean bottle. Ran it down to 1/4 tank, poured it in, 20 miles later filled the tank.

CAT monitor wouldn't clear. Ran through the whole tank, still didn't clear. Tried all kinds of stress driving and drive cycles (high revs, manual shifting, and all the crazy drive cycles). Still didn't work.

When tank was almost empty, kind of gave up. Was about to take a week's vacation, so stopped checking with the OBD reader. Filled it up right before I left, the car sat for a week, then came back and just drove it normally for another week.

Just hooked up the reader -- lo and behold, the angelic "P1111" was showing. Green lights across the monitor board! The CAT monitor had finally passed its test! Woo hoo!

Now, I don't know how much the Cata-Clean had to do with this. I don't know what finally triggered it. But then again, neither do professional Jag mechanics, so I don't feel too bad. All I know is I used it, and it took much longer than I thought, but eventually it seemed to do the job. So I would semi-endorse the product for others to try. Follow the instructions, and don't be too dismayed if it doesn't seem to do anything right away (or even to the end of the first full tank).

That was my experience, anyway. Thanks to everyone who offered advice and suggestions, and I hope this final post helps someone in the future.
 
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Old 08-20-2017, 02:35 PM
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That's great, I honestly think it was persistence and not the overpriced Cata stuff. But for the technicians (don't call them mechanics, I made that mistake with my indy), they were doing you a justice and saving you the monitor costs, kudos to them as you state "for being honest".
I have to ask, what does Cali require (if any) on your saloon (primarily exhaust) that the rest of us civil minded automobile driving states don't require?
 
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Old 08-20-2017, 04:46 PM
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I'd put little or no faith in the miracle juice. Stories of one or more monitors taking forever to set on these cars are quite common. Just keep driving i the norml cure.

This inconvenience is solely the fault of using the OBDII system for something it was never designed for. Hopefully OBDIII might dress these shortfalls.
 
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Old 08-20-2017, 05:54 PM
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Probably something is marginal and will in due course flag code(s) but for now be glad it was "working" enough to set the monitors and pass.

Cali's changed requirements (you'd have been OK previously) make no sense to me.
 
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Old 08-21-2017, 10:04 PM
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Highhorse -

Yeah, that's why I only said "semi-endorse." Dunno what went right finally, but did want at least one "I made it out the other side" story for people who search the site.

As for Cali, the law passed two years ago. My last smog check back then passed with no problem.

New law: only the EVAP monitor can be in the red. ALL other monitors must clear. No exceptions, no excuses. I was about to look into a "smog referee" who could have given the car a ONE-TIME 2 year exception. It's got 140K on it, so another 2 years might have been about right. But that's the law going back to the 2000 model year. I think 1999 and before you can have up to two monitors in the red and still pass smog.

If I hadn't resolved the problem, my only real option was to sell the car out of state.

Mikey -

Yeah, I've heard the ODBIII is looking at the monitor issue too. The mechanic, oh, excuse me, technician did say that the CAT monitor was an odd one not to clear. He said he'd had problems with other monitors that sometimes took 2 months to clear, but never the CAT.

JagV8 -

Well, hasn't passed yet -- smog appointment is tomorrow. Wish me luck! See above for what I found out about new CA law...

Thanks to all for responding!
 
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Old 08-22-2017, 01:57 AM
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Good luck!
 
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Old 01-20-2018, 10:01 PM
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Default cat monitor

I work at an indy jag shop. Call me a tech, call me a mechanic, call me Ishmael.(for those who didn't get that look up Herman Melville). Makes no difference to me. I have a 2000 XJ8 with a smog check coming up, and the cat monitor has not set. And I live in Ca. But I'm not worried. I've seen so many of these cars take a long time for this monitor or that monitor to pass that I know it will happen eventually. My customers always want a magic answer but all I can tell them is DRIVE THE CAR!
 
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Old 03-11-2019, 07:50 PM
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I keep thinking about the constant instructions to disconnect the battery every time you do some work on the car, including when it appears hardly necessary to do so because the work being done is hardly electrically related.
Yet, every time you do this you're having the ECU disconnecting and re-connecting (i.e. restarting) all of the I/M readiness monitors and, yes, including the hideous CAT monitor. These instructions should add a specific tip not to disconnect the battery if you're anywhere within 6 months of registration renewal time and that smog is also due that year. I paid my XJR registration back in November, yet I still cannot dare to drive it because the cat monitor is still not ready. Is this exclusively an XJR problem? If so, there must be something wrong with the design of the signal flow in and around this car's ECU. Why so many Jag fellows here with this problem? Is it just a Jag thing?
 
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Old 03-12-2019, 06:33 PM
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​​​​​​As I mentioned in other threads before, they should be able to set within 10-20 km, as long as it includes some stop and go, city driving, and a highway part.
I always disconnect the battery while parking, and both my XJ8 and XK8 do it without a problem.
There must be something missing or wrong in the various parameters if it doesn't.
 
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Old 03-12-2019, 11:57 PM
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Originally Posted by beauregard View Post
I work at an indy jag shop. Call me a tech, call me a mechanic, call me Ishmael.(for those who didn't get that look up Herman Melville). Makes no difference to me. I have a 2000 XJ8 with a smog check coming up, and the cat monitor has not set. And I live in Ca. But I'm not worried. I've seen so many of these cars take a long time for this monitor or that monitor to pass that I know it will happen eventually. My customers always want a magic answer but all I can tell them is DRIVE THE CAR!
Hi beauregard,

The attached document refers to 2004 models, but it might be worth trying the Catalyst Efficiency Monitor Drive Cycle on pdf page 4 to see if it helps expedite the readiness monitor reset. Drive Cycles for other monitors are also listed.

I'm assuming you have no DTCs stored or pending? How are your STFTs and LTFTs? Any signs of lean or rich running? Any possibility of an exhaust leak? How do the O2 sensors behave while watching Live Data?

If your scan tool can read the Mode $06 hexidecimal data, you may be able to see some clues as to what is going on.

Cheers,

Don
 
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Last edited by Don B; 03-13-2019 at 12:19 AM.
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Old 03-14-2019, 06:01 PM
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As I said in a post about a year ago, no magic answer. Drive the car like you stole it. Mine passed shortly after my post. I am continually telling people that just because a monitor won't run dosen't mean there's something wrong. I was having lunch with a couple of friends who work at the jag dealership and told them I was helping a friend get a 2001 xj8 to run the cat monitor and they laughed and said "have fun".
 
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Old 03-14-2019, 06:03 PM
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All parameters good. Have ability to see all info mentioned. Seen alot of these cars over the years.
 
 

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