loustylez

most important info:
2001.5 A4 2.8 QT 104k miles sport convenience, etc. all stock except a couple cosmetic exterior things.

the code it's throwing is P0430 - Cat inefficiency

first time it was reset, came back about 2-4 weeks later

second time, same

third time, same

just had it reset again and i'm waiting to see if it comes back. it most likely will.

i wouldn't have much ground to stand on if i were to say that when it gets reset, the engine seems to generally run slightly better, with a smoother ride through the power band - more even and consistant (hard to tell for sure it's slight enough to make you second gues yourself) and shifts slightly smoother between gears. i recently had a tranny flush which seems to have helped out quite a bit, but then again at the same time the CEL was reset again. it has slowly, possibly, seemed to be getting ever so slightly worse (not shifting as smooth). this, again, seems to be the case almost every time i've gotten it reset. i leave going "yah... this might actually be shifting smoother" and... again... it's hard to tell if i'm really noticing a difference because it's hard to tell if i'm noticing a pattern or not.... but i think i am, because i know i'm pleased enough to be hopeful the smoothness lasts after it gets reset and i'm looking for a change... and now i'm back to questioning again, so that has to say something.

a search here has returned that there was a tech service bulletin (C260503) that mentions this is part of a known issue w/ the o2 sensors throwing a CEL for the cats when, really, they're fine.

i'm having trouble knowing if i'm correct in getting the impression that this is something covered by the dealer that i can just go in and get fixed or if it's something i'll have to pay to get done either way. i bought the car from a small import dealer and it would be out of warranty either way.

any experience on this or suggestions for what action to take at this point? i think most other's reply were based on being just BARELY out of warranty and trying to get the dealer to pay for it anyway. i'm assuming if this is the case, i may have to fork out something either way... but at least it's not $2,000 to get new cats or something.

Shep 1.8T

normal stuff.

There are a couple of probable things that are causing this, the first of which could be a dead rear 02 sensor. That rear 02 is looking for a difference in oxygen readings between pre and post cat, and if it's not seeing a high enough difference you'll have a failed cat effiency readiness.

The second possibility is the cat's ability to convert the unburned fuel into c02, water, etc is degraded to the point it's not working as well as originally designed.

There is a very good chance that neither of them will matter for emissions purposes. Which in the end is all that really matters.

I have 100K miles on my 97, and my hi flow cat is about the size of a coke can. I had a failed cat effiency code when I went on the rollers for emissions, and passed with flying colors, in fact I hardly produced any emissions at all. I'm thinking I might have been able to run the car without a cat all together and still passed.

loustylez

"generally emissions related items are covered by a different warranty that last much longer than
Posted by: Shep 1.8T on 2006-11-10 01:13:16
Account #: 48848

In Reply to: cat inefficiency CEL P0430, suggestions posted by loustylez on 2006-11-09 23:51:38

normal stuff."

does this apply if i don't have a warranty at all?

BikerBill

In March of this year I had problems getting codes of P0421 and P0431 which were attributed to catalyst warm up efficiency being below threshold. As in your case, at first it took weeks to successively throw the CEL. After months the CEL was on all the time. I did some checking around and found this was not due to bad O2 sensors or bad cats. Below is an extract from an earlier posting I made. It's now been 7 months since I had the IC sevice action performed and I've not seen the CEL once in that time. Good luck!

The IC service action is a technical service bulletin issued by Audi to address the issue of false catalytic converter problems. It's basically an unannounced recall. Your car has two pre-catalytic converters. There is an oxygen sensor before and after each pre-cat(total of 4 sensors). The engine control module compares the signals from the sensors before and after each pre-cat to ensure the pre-cats are working properly. It seems that Audi made this comparison too stringent, which triggered a bunch of false check engine lights. In July of 2005 Audi issued a fix for this problem, which is a download of new firmware code for the engine control module.

My CEL was on intermittently for many months and then on constantly for several more due to the codes I mentioned before (P0431 and P0421). Since the update of my ECM it has been off straight for over 2 weeks now. My car just passed state inspection with no problems after the update. I thought I would need new cats to pass inspection.

I have a 2000 A4 2.8 Quattro with an engine code of ATQ. If you call your local dealership and give them your VIN they can tell you if your car is subject to this service action and if the service action has been performed. If you have your car serviced at an Audi dealer and the car is affected by this action, it should have been performed already, assuming you've been in after last July. But I'd certainly ask specifically for your car. I have been told this problem affected 2000 and some 2001 Audi's.

Since this affects emission performance there is an 8 year/80K miles warranty compliments of the Federal government. Audi of America says the dealerships will charge after that. My dealership (which I virtually never visit) did not charge for it and my car has 130K miles. I was told it takes 1-1.5 hours to do this, but once they link your car to Audi's computer it's just computer to computer data transfer time.

If you gutted your pre-cats this obviously won't apply. If your pre-cats rattle when you tap them with a rubber mallet then the ceramic matrix is likely broken and you will need new cats. But if you're just getting a CEL and the codes above (Autozone can read out the codes in 2 minutes for free) and your mileage and driveability are good I would definitely check into this. In the greater Boston area two cats installed by an Audi dealer are over $4000.

For sure, the cheapest and easiest fix is the one you don't have to do!

loustylez

excelent information. much appreciated. hopefully molle will be kind enough to do it for me since i already paid them to have the car inspected before i bought it AND paid them to get my radio code.

dferris40

Is this a major problem? What is approximate repair cost?