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Discussion Starter #1
I haven't had the P0420 code rear it's ugly head in over a month now, the electrical Gremlins must be taking a Christmas break. LOL :D Sure glad I didn't change out the Catalytic though. Babyblue passed emissions with flying colors the other day, life is good. If you are reading this and have the dreaded p0420 code double check all the emissions system components before just changing out parts, especially expensive ones like the catalytic. Good luck folks and Merry Christmas ..:)
 

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Discussion Starter #4
p0420

Not sure if it had something to do with the Mayan calendar or what but I know it has not come back for a month now. @billymade I am not sure but tracking back step by step on what I did the last month; changed plugs, cleaned throttle valved,put new air filter, put a bottle of lucus oil in the gas tank(sorry indytom I know you were hoping I'd say seafoam) LOL :D and started using 93 octane TEXAS grade gas..LOL :p I'll keep you posted if that code stays gone forever. @Indytom I would have used a piece of black Tape to cover the light if I could get away with it but the GODS OF EMISSIONS TESTING didn't think it was funny.
 

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Not sure if it had something to do with the Mayan calendar or what but I know it has not come back for a month now. @billymade I am not sure but tracking back step by step on what I did the last month; changed plugs, cleaned throttle valved,put new air filter, put a bottle of lucus oil in the gas tank(sorry indytom I know you were hoping I'd say seafoam) LOL :D and started using 93 octane TEXAS grade gas..LOL :p I'll keep you posted if that code stays gone forever. @Indytom I would have used a piece of black Tape to cover the light if I could get away with it but the GODS OF EMISSIONS TESTING didn't think it was funny.
LOL :p Black tape works here in Indiana. We have cars driving around blowing black smoke for miles and nobody cares.
No emission testing here in the land of corn, soy beans and water melons. Which is not necessarily a good thing.
I am from Germany and over there you have to get your car inspected and TÜV approved. Heck if you have a rust spot on your door you won't pass.
You can not even put larger wheels and tires on the car unless you have them approved by the TÜV and they are entered in your Registration.
Very, Very Strict over there. However, they only have to get their cars inspected and tested every 2 years.
 

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Discussion Starter #6
update

Update Update; The infamous P420 code came back the other day it just seems Odd that it happened the exact afternoon that we got a blue northern cold front come in. In Texas weather you could be standing outside at 70 degrees and when the blue northern arrives it drops temperature to 50 degree in 10-15 minutes, weird. Well anyhow the code came back but this time it was gone for 1.5 months-just fyi. Don't have time to troublshoot right now too many other things to do with my life than chasing a stupid code..LOL :p
 

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Get VAG-COM hooked up to the car and take a peak at your O2 sensors just to be sure they are in good shape. I would still think it could be the cat, as that's what this code *usually* means.
 

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Rarely the converter being bad. These codes can be a PITA as they can be very sporadic.

A few things you need to check carefully:

1. Engine operating temperature, 1.8 should run about 200F-205F from what I have seen.

2. Post cat exhaust leaks and for hairline cracking around O2 sensor bung welds. These cars have the post cat exhaust sleeve and I do not trust these much for properly sealing.

3. O2 sensors. Given the age of the car, replacement sensors may be due? If you have the ability to graph the O2 sensor Voltages this is something I would suggest.

Also check to see if you have freeze frame data for when the code is triggered as this may offer more clues?

I many times see these codes triggered under VERY light throttle when cruising the highway. I assume your CEL came on during a highway run?

If you feel you have to replace the cat, I just recently purchased a decent one from ebay that was $248 delivered on my doorstep with a gasket. Nice welding, OE style flex joint. I tossed a new Bosch front O2 sensor in the car and put a new rear pipe coupler on the car. My problem was with a fractured monolith, I had a large gumball size part of the monolith dancing around between the first and 2nd cat chamber. Too big to come out via the O2 sensor hole.

Not sure why it broke, no melting, either shipping damage or manufacturing issue?
 

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Discussion Starter #10
no cat yet

Rarely the converter being bad. These codes can be a PITA as they can be very sporadic.

A few things you need to check carefully:

1. Engine operating temperature, 1.8 should run about 200F-205F from what I have seen.

2. Post cat exhaust leaks and for hairline cracking around O2 sensor bung welds. These cars have the post cat exhaust sleeve and I do not trust these much for properly sealing.

3. O2 sensors. Given the age of the car, replacement sensors may be due? If you have the ability to graph the O2 sensor Voltages this is something I would suggest.

Also check to see if you have freeze frame data for when the code is triggered as this may offer more clues?

I many times see these codes triggered under VERY light throttle when cruising the highway. I assume your CEL came on during a highway run?

If you feel you have to replace the cat, I just recently purchased a decent one from ebay that was $248 delivered on my doorstep with a gasket. Nice welding, OE style flex joint. I tossed a new Bosch front O2 sensor in the car and put a new rear pipe coupler on the car. My problem was with a fractured monolith, I had a large gumball size part of the monolith dancing around between the first and 2nd cat chamber. Too big to come out via the O2 sensor hole.

Not sure why it broke, no melting, either shipping damage or manufacturing issue?
Hey thanks for the Information really apreciated. :)
 

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Discussion Starter #12
Cat

Muffler Express out of Canada. Quick shipping, good quality, comes with flange gasket and fit well.

Suggest you get new nuts from the dealer for the turbo flange side. Dealer has the connection sleeve, however, you may be able to reuse your current one.

2002 2003 2004 2005 VW Beetle 1 8 1 8T Down Pipe Catalytic Converter New | eBay
HEY thanks for the information I agree with you it's rarely the cat converter that is bad, I don't believe it is because it's been throwing this code on and off for the last 3 years now, comes and go's like the wind...LOL :tongue:
 

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HEY thanks for the information I agree with you it's rarely the cat converter that is bad, I don't believe it is because it's been throwing this code on and off for the last 3 years now, comes and go's like the wind...LOL :tongue:
Yea, this is nothing specific to VW, some manufacturers even had software updates due to the test window being too narrow and trigger "phantom" cat efficiency codes. I believe that I had this code on my 2003 while still under warranty and they changed the converter. Not sure if this was due to cracked O2 bung welds or exhaust leaks at the coupling joint. I was surprised that these cars actually have the coupling joint post cat, most cars have fully welded exhaust these days.

I would say post cat O2 sensor or exhaust leak of some sort, but if it only happens occasionally, I would clear the code and move on. You could always try to smoke test your exhaust system to check for leaks if you were so inclined.
 

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Discussion Starter #15
totally cool

This may be of interest to you for your P0420 code?
Super thanks man, you're my savior man I will look into that. I knew this whole time it couldn't be the CAT becuase the folks at the emission place would hook up their machine on the tail pipe and never saw andy faults. THANKS again :banana:
 

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Super thanks man, you're my savior man I will look into that. I knew this whole time it couldn't be the CAT becuase the folks at the emission place would hook up their machine on the tail pipe and never saw andy faults. THANKS again :banana:
You must live in one of the three counties in the entire State of Texas which smog test. You poor thing. If I were you, I'd move out of that county. Or vote the County Council OUT and vote in real Texans. :mad:
 

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You must live in one of the three counties in the entire State of Texas which smog test. You poor thing. If I were you, I'd move out of that county. Or vote the County Council OUT and vote in real Texans. :mad:
Yeah, like Walker Texas Ranger :D

Or me. I am a Texan with German decent ;) Hey, maybe I can be Governor of Texas. Nah, who ever heard of a German accent speaking guy becoming Governor ;)
 

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Discussion Starter #18
Lol

Yeah, like Walker Texas Ranger :D

Or me. I am a Texan with German decent ;) Hey, maybe I can be Governor of Texas. Nah, who ever heard of a German accent speaking guy becoming Governor ;)

Only in Hollywood indytom. So you speak German fluently super indytom? Sorry maybe this thread is going off topic.:eek:fftopic:
@mrsbeetle, In fact I live in Fortbend County which is right outside of Houston and we do have emissions testing..UURRGGG!
 

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Discussion Starter #19
Dealer

This may be of interest to you for your P0420 code?
So do you think this is something that has to be done at the Dealer? or perhaps with a VAG-COM? For a few bucks I don't mind the dealer flashing me..LOL :p OOP's I meant flash my ECM or program/update my car computer. I'd be too scared to try with my secondhand vag-com I got. LOL :eek:hnoes: HAS ANYBODY HERE EVER DONE THIS BEFORE???
 

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Only in Hollywood indytom. So you speak German fluently super indytom? Sorry maybe this thread is going off topic.:eek:fftopic:
@mrsbeetle, In fact I live in Fortbend County which is right outside of Houston and we do have emissions testing..UURRGGG!
Hey, I am born and raised in the land of Arnold Schwarzenegger. ;) Actually, he is from Austria. I was born and raised in Deutschland. ;) Army Brat. My mom was German and my dad is American.

German was my first language.
 
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