Please Help - Catalyst Monitor Inc - not ready

[abcxyzzz]

Hi, I have a 2004 A4 3.0L Quattro Avant. I live in California.

Recently the Check Engine Light has been on. I have to get a Star Certified Smog Check soon.
I reset the codes/monitors and 7 of the 8 are ready, the only one that is not is the Catalyst Monitor. I've driven in various conditions for over 300 miles the past 2 weeks and it's still not ready (CEL is still off, which is good).

I read somewhere that 2001 and newer cars can have 1 monitor not ready and still be able to pass the smog check, is that true? And if it's true, does that apply for a Star Certified Smog Check station as well?

How can I get it this last monitor to complete the drive cycle and have all 8 monitors ready?

Any help would be much appreciated. Thanks!

[audireme]

In CA you can only have an EVAP monitor failed, no other. And no CEL at all. Your post cat O2 sensor may be bad.

[SJorge3442]

That means the test hasnt ran yet. If you have VCDS you can force the test to run. Im thinking you're gonna need an o2 spacer. Audi pushed for a ULEV rating on the 3.0, which means the car will trigger a below efficiency code (p0420 and p0431) very easily. It just means the cat is below is proper threshold to maintain that crazy ULEV rating.

[abcxyzzz]

Thanks for the replies.
I don't have VCDS. Not sure why the drive cycle still hasn't completed that monitor after driving 300+ miles already.
What is an o2 spacer? I see that in some messages, but not sure what it is or how to install it, is it very difficult?

Audireme, would a bad post-cat o2 sensor cause the catalyst monitor readiness to be incomplete?

[ErikG]

abc- search the forums for driving cycle. There are a few posts about it. If you run through the test, all driving cycles will be tested. Depending on how you drive, it may never get into the specific conditions required to begin the test that has not been completed.

I had cleared a CEL before and it took 150 miles or so to come back on because of how i was driving it. Found the driving cycle test and was able to replicate the CEL reliably so i was able to make changes to the car and test rapidly, fixing my secondary air injection fault.

-E

Edited to add:

I had taken my car to the smog shop and it failed do to not having completed the full driving cycle test, so even if you can have 1 test failed(which i dont believe is true) the full driving test must be completed before a smog can be performed.

[SJorge3442]

Thanks for the replies.
I don't have VCDS. Not sure why the drive cycle still hasn't completed that monitor after driving 300+ miles already.
What is an o2 spacer? I see that in some messages, but not sure what it is or how to install it, is it very difficult?

Audireme, would a bad post-cat o2 sensor cause the catalyst monitor readiness to be incomplete?

A spacer moves the o2 sensor up out of the direct path of the exhaust gases, thus reading a lower rate of unacceptable fumes. Sometimes if its moved too far out of stream it can cause issues too. For the 3.0 they are a bitch to install. Because I live in PA and I'm allowed to have a failed emmissions code, I just live life with my CEL popping up from time to time.

[pablolizarraga]

The catalyst monitor has been one of the last ones to clear when I've done the drive cycle.


Seems like catalyst readiness requires sustained hwy cruising of 5min; which depending on where you live in CA can be difficult to do.

Refer to pages 1-3 on the link for detail info on how to conduct drive cycle. It may help with running the last monitor.
https://www1.snapon.com/Files/Diagno...CodeCharts.pdf

Either way, you should get fault codes checked. They may point toward the O2 sensor, catalytic converter, both, or more.
Good luck.


Sent from my iPhone using Audizine

[abcxyzzz]

Thanks for the chart and pdf link, it's quite helpful. The only one of the 8 that is incomplete is the Catalyst Monitor, and from the chart and pdf link you sent, it shows the "drive style" needed to monitor the Catalyst is the steady driving at 55mph to 60mph for 5 mins. My wife drives the car to and from work, but not sure if it's steady at that speed for 5 mins since it's rush hour both ways. I drove to and from the airport the past 2 days at a steady speed of 75-80mph for 15 mins at a time, is that too fast then? If so, maybe i'll take it out tonight and just go the 55 to 60mph and see if that works? What do you guys think?

The original fault code was a P0420 which is a bank 1 low efficiency catalyst. The light comes on for months, then will go off for months. So I was reading it could be a faulty switch sensor or something. So, suggested tactic was to reset the codes and see if the light comes on again. I guess if it's really faulty, if/when the catalyst monitor is ready and the light comes on again, then there's really something wrong right?

[SJorge3442]

Thanks for the chart and pdf link, it's quite helpful. The only one of the 8 that is incomplete is the Catalyst Monitor, and from the chart and pdf link you sent, it shows the "drive style" needed to monitor the Catalyst is the steady driving at 55mph to 60mph for 5 mins. My wife drives the car to and from work, but not sure if it's steady at that speed for 5 mins since it's rush hour both ways. I drove to and from the airport the past 2 days at a steady speed of 75-80mph for 15 mins at a time, is that too fast then? If so, maybe i'll take it out tonight and just go the 55 to 60mph and see if that works? What do you guys think?

The original fault code was a P0420 which is a bank 1 low efficiency catalyst. The light comes on for months, then will go off for months. So I was reading it could be a faulty switch sensor or something. So, suggested tactic was to reset the codes and see if the light comes on again. I guess if it's really faulty, if/when the catalyst monitor is ready and the light comes on again, then there's really something wrong right?

if its a 420, its due to the cat not working 100%. Or it could be a bum o2 sensor. If its a cat issue, the o2 sensor spacer will solve your problem. If its a sensor issue, you need a new sensor. I'm pretty sure you need to follow that drive cycle 100% to solve the readiness. I don't think you can skip to any one portion without first completing the earlier steps.

[abcxyzzz]

if its a 420, its due to the cat not working 100%. Or it could be a bum o2 sensor. If its a cat issue, the o2 sensor spacer will solve your problem. If its a sensor issue, you need a new sensor. I'm pretty sure you need to follow that drive cycle 100% to solve the readiness. I don't think you can skip to any one portion without first completing the earlier steps.

Oh, so you actually have to drive in that order even if only the catalyst monitor is showing incomplete but the other 7 are good to go? I've been reading that from the time you reset the codes, normal driving distance (all types of driving style) is around 50-100 miles. The 12 minute cycle on the chart surely won't go that distance?

[old guy]

The ECU utilizes the rear O2 sensor to monitor the cat efficiency. It doesn't do it on a continuous basis. It takes readings under specific conditions. By utilizing the drive cycle you can invoke several of those reading conditions. However, just driving the car normally for a day or two does the same thing. Here's some detail on what the ECU is looking for: Clicky click® It's all about monitoring and comparing the switching rate of the front and rear sensor.

Typically when the cat starts to fail you will get a CEL for a day or two that goes away on its own. If the ECU passes two consecutive tests the light will go off. If the cat fails another test the light goes back on. As the cat deteriorates the light will come on more frequently to the point where it just stays on all the time.

O2 spacers function by pulling the sensor partially out of the exhaust stream in an attempt to mask the switching rate. If it is too far out of the stream it will mask the switching rate altogether and the ECU will assume a failed cat. Here's an alternative to simply running a spacer. Clicky click® The "mini cat" pulls the sensor partially out of the exhaust stream and can actually do a small amount of scrubbing to mimic the O2 store/release cycle of a functioning cat.

[abcxyzzz]

Update: So, I had told my wife this morning to try to drive between 50-55mph for like 10 mins. When I got home tonight, I checked the monitors with the OBDII scanner and the Catalyst Monitor is now ready! SO not sure if it was because she drove it 50-55mph (she said she could only do it for 5 mins), or if just enough time passed, it's been like 300+ miles.

So I need to get it smogged asap before the CEL comes back on. My question now is that I looked at the smog reports from two years and it seems to NOT have HC, NO and CO readings, there's no quantitative numbers on the previous report, but prior reports from 2013 and 2011 did had the HC and CO readings. My 1998 BMW that just failed has quantitative measures for each of those HC NO and CO. Is that because my BMW is 2000 and older and this A4 is 2000 and newer? If that's the case, do i still need to drive it 20 mins on the freeway to have the car warmed up and the cats hot in order to get the smog check?

[old guy]

It depends upon the type of test performed. I don’t know the methods employed in CA but I assume that they are similar to MD. Any newer vehicle with a OBDII port gets checked by plugging into the tester and checking the readiness switches. If the readiness switches are all “0” you pass. So as long as your readiness switches are set to "0" you should be good to go.

On older vehicles without OBDII support an exhaust gas sniffer is used. That’s when you get the print out of the hydrocarbon levels. If a sniff test is being performed it would be a good idea to have everything fully up to temperature.

[abcxyzzz]

So I just drove around for about 20 minutes and went to the Smog Station and it passed. They didn't do a dyno cuz I have a Quattro 3.0L, so all they did was visually inspect and then hook it up to the computer and it passed. Not sure how I have prior readings of HC and NO and CO on prior year's smog reports. Do they have dyno's for 4 wheel drive? I didn't remember paying too close attention before. So it passed, thanks all for your replies.

Now, I have to figure out how to pass my 1998 BMW 328 that failed 2 weeks ago with high HC and high NO. That registration is due next week! Apparently I had the same issue 5 years ago failing with high HC and high NO, then I put Guaranteed to Pass solution in the tank and drove it to empty during the week and filled it up and then drove it hard before getting the smog check and it passed, but barely. Trying to do the same thing, but worried it might not work this time. Anyway know the cause of high HC and high NO readings?

[old guy]

BMW needs a new cat.