# 2004 V6 Touareg catalytic converter failure



## LuvMyRex (Dec 17, 2003)

Hi all, looking for some advice....

Both the front and back catalytic converters are throwing codes according to my mechanic and he is giving me a couple options.

First, a bit of background:

- My 2004 Treg had the coils replaced a few years back as a result of the recall that went out but not sure if that has anything to do with the cat. converters...just an FYI. 

- About three years ago I began to notice that the idle would be elevated (around 1,300rpm) for about 30secs on a cold start before settling back down below 1,000rpm. I asked my dealer about this and they indicated it wasn't abnormal.

- About a year ago the dash emission light came on for a couple weeks and then went away. It happened again a couple months after that. Another two or three months after that and it is now perma-lit.

- My wife took it to a 'drive-clean' emissions test garage and it failed. I learned that they weren't measuring the tailpipe but, rather, reading the codes (which according to my mechanic is pretty standard practice now).

- From a 'smell-test' perspective, I do notice a hint of unburned gas smell when it is running. Which could mean the problem is at the engine?

So, I can get both converters replaced for a cost of around $2,500 or have a part installed for $500 which will prevent the OBD codes from tripping which gets me a drive clean pass. My mechanic indicated that the converters are running at around 90% capacity after testing them.

So what do you think I should do? Cost is certainly a consideration unfortunately.

Could there be something else causing the emission system to throw these codes?

Thanks for any and all helpful advice!


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## JeremiahSOW (Apr 9, 2007)

What are your codes? Could be faulty o2 sensors. You could have high flow cats installed for way less than even a grand. For $500 he better not be installing o2 spacers. That would be a wicked ripoff.


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## LuvMyRex (Dec 17, 2003)

Just an update to close out my original post.

The cats were structurally ok but were running around 90% of full efficiency according to my mechanic. 

I added a pint of pure acetone to a half tank of gas after having my mechanic reset the codes. Took it out for a 60mi ride on the highway at 60mph in 4th gear to hopefully cook out/burn off anything coating the catalysts.

A couple weeks later and the check emissions light has remained off and the vehicle passed its emissions test.


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## KKToureg (Sep 1, 2004)

*Is it safe and where do you buy pure acetoone?*

I'm running into the same scenario. 2004 V6 with 150K miles. Engine light was on with CAT code and had them zeroed out and waiting now for my car to 'relearn' emission data for the SMOG test. Adding a pint of pure acetone to a half tank of gas sounds scary (for my car) but if it means passing the emission test vs. replacing the catalytic converters, I'm willing to try it. Is it safe to add and where do you buy pure acetone?


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## rinaic (Mar 23, 2004)

Acetone available in the big box home improvement stores.
Same aisle as paint thinner and other cleaners/strippers.

Cat replacement is the last ditch effort.

The acetone will probably buy you enough time to pass the emissions test. Just remember you have to drive a certain amount of highway and city time after clearing the codes before you can go in for testing.

When looking for issues first look at the 02 sensors and then check the related vacuum lines.


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## KKToureg (Sep 1, 2004)

*update for me*

I passed the SMOG test today. I did not go the pure acetone route. Just had the CAT code cleared, drove the car enough to establish an emission history and passed the test. My theory is that once the CAT codes are issued they never clear, regardless of the catalytic converter's performance. I've been through this scenario twice now (in the past 4 years) and both times the code was issued as I was driving in a stop and go fashion (once in a parking lot and once in a fast food drive through); I suspect in those instances the catalytic converter was not optimally performing - no big surprise. I expect to see the check engine light come on sometime again in the car's lifetime but getting the code cleared is my preferred alternative to spending $2130 on a catalytic converter that isn't justified to correct a phantom emissions issue.


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## JohnKK (Aug 30, 2004)

*spacer inserted at post cat O2 sensor will fix this for good*



KKToureg said:


> I passed the SMOG test today. I did not go the pure acetone route. Just had the CAT code cleared, drove the car enough to establish an emission history and passed the test. My theory is that once the CAT codes are issued they never clear, regardless of the catalytic converter's performance. I've been through this scenario twice now (in the past 4 years) and both times the code was issued as I was driving in a stop and go fashion (once in a parking lot and once in a fast food drive through); I suspect in those instances the catalytic converter was not optimally performing - no big surprise. I expect to see the check engine light come on sometime again in the car's lifetime but getting the code cleared is my preferred alternative to spending $2130 on a catalytic converter that isn't justified to correct a phantom emissions issue.


the post cat O2 sensors trigger this and the CEL lights up far before you ever need to replace CATS. Unscrew the rear sensors and screw in the spacers. Then screw each O2 sensor into the spacer. These spacers are available ready to go or you can buy a HELP spark plug spacer and drill it out with a 1/2" bit so that the sensor will screw in easily. With the spacer in place, clear the codes and forget about it failing inspections until the CAT literally falls apart.


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## KKToureg (Sep 1, 2004)

*2 years and 25K miles later and CAT code comes back during drive cycle*

Hi there, It's two years later and getting ready for a smog and I've had the CAT code cleared twice in the past week and each time they've come back attempting to complete a drive cycle. My mechanic is recommending replacing the (front) catalytic converter because getting to the O2 sensor is as labor intensive as replacing the CC (12 hours!). Cost is around $3K. I have 175K on my 2004 V6. Should I give the acetone treatment a shot? Any suggestions?


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## KKToureg (Sep 1, 2004)

*let me restate: replacing O2 sensors may not fix the problem and cost is $1lk*

Wanted to restate what my mechanic said. The cost to replace the front and back O2 sensors is $1K in parts (4) alone and no guarantee that the CAT code will be resolved. Replacing the CC is $3K and would resolve the CAT code.


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## KKToureg (Sep 1, 2004)

*what can I expect next at 175K miles*

We need to hold onto this car for another 2 years and in terms of mechanical issues we've already replaced front and back drive shaft, battery, fuel pumps and driver side ball joint. Are there other likely failures ahead?


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## krwwc6 (Jun 26, 2010)

I think for those prices you may want to look into another mechanic.


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