I have a 2002 A6 3.0 Avant with 148K miles. I replaced both catalytic converters in 2007, now I'm told they need replacing again. This seems preposterous to me -- is this common among Audis? Is it possible that something else is causing this fault and that the cats are actually okay?

 

a lot of dealers or mechanics will tell you that the cats need replacing when in fact, they are perfectly fine. they like to make money,not necessarily take care of their customers.

if you have a check engine light on,get it scanned for free at autozone and check the codes online.

i know of more than a few people that were told they need a new cat (or more), but the problem was just a dirty mass airflow sensor.

as long as you havent had any serious problems (like unburnt fuel pouring into everything as a result of failed coil packs or related), i highly doubt theres anything wrong with the catalytic converters.

 

Thanks very much. I had AutoZone pull the DTC -- it is P0439. The description says: "The PCM has determined that a malfunction exists in the control circuit for the catalyst heater in bank 2." Near as I can tell, bank 2 means driver side. So the next question is how to know whether it's the O2 sensor before the catalyst or after?

 

Test if the O2 sensor is good or not, as it is much cheaper to replace.
You can change the left to right and see if the code follows it.
One of the method
http://www.youtube.com/watch?v=1mb4VmDd0ao
Another way to test
http://www.youtube.com/watch?v=vdn4Dk5PSwc

 

several dealers recommend to only replace the Cats with OEM and NOT after market even if you can save $400 or so with aftermarket ones. Some people have replaced with aftermarket ones and a few years later have issues again.

 

They don't call them the Stealer....er....Dealer for nothing. That error code is the heater circuit in the O2 sensor not a bad cat. Cats will last for at least 15 years unless you start burning a lot of oil. The price of those things is damn ridiculous...

 

Re: Catalytic Converter Lifespan?

Based on my experience with our 2000 Audi A6 Quattro, we replaced our cats last year (2014). The shop (which specializes in German cars) where we had the work done mentioned they have seen this issue on quite a few Audis of similar age.

Cannot state the following as true but based on the shop team's and several other shop's opinion, they have seen much better longevity results when the owner only replaces the cats with OEM cats and NOT cheaper aftermarket cats. Several shops told me that within a few years, some customers which chose to save money by having aftermarket cats commented they did not pass inspection in some cases as early as 3-4 years after installation while customers that chose OEM ones had many more years of no further issues.

I noticed in your posting you did NOT mention if you went with OEM or aftermarket cats when you had them replaced.

Another item worth mentioning is that I take it for granted people always put Premium gas when filling up a high performance type auto. However, I have come across several people that have spent quite a bit on a new Q7 or other newer Audi and put in regular unleaded gas which I had no idea some people do. There is no question a lower grade of gas can definitely impact the longevity of Catalytic Converters.

LP

 

I cannot see spending close to half the book value of the car on new OEM cats. I also don't think it's as much the octane rating of the gas we use, it's the CRAP ethanol that we are being FORCED to use in most gasoline you buy. Ethanol in gasoline is possibly the biggest con ever in the petroleum history. If offers zero point zero (in my best Dean Wormer voice) benefits in fuel mileage or performance. In fact it is detrimental to both. Not to mention corrosive to older fuel systems. Especially small engines. They want green energy, well, THIS is the only green, I've ever seen ethanol deliver.

<a href='http://postimage.org/image/epjjbsuih/full/' target='_blank'><img src='http://s20.postimage.org/42pq6dmd9/0402141847.jpg' border='0' alt="0402141847" /></a><br /><br />
<a href='http://postimage.org/image/pdnaan4hl/full/' target='_blank'><img src='http://s20.postimage.org/cz0iabczh/0402141841a.jpg' border='0' alt="0402141841a" /></a><br /><br />
<a href='http://postimage.org/image/m82okflvd/full/' target='_blank'><img src='http://s20.postimage.org/5kb6hxr3x/0402141842.jpg' border='0' alt="0402141842" /></a><br /><br />
<a href='http://postimage.org/image/j2i2u8395/full/' target='_blank'><img src='http://s20.postimage.org/6nvatwbr1/0402141841.jpg' border='0' alt="0402141841" /></a><br /><br />
<br /><a target='_blank' href='http://postimage.org/'>pic host</a><br /><br />