# Check engine code P0420???



## queensfinest (Aug 11, 2006)

I went to Auto Zone yesterday to try and diagnose the reason my check engine light came on and it read P0420 Catalyst efficiency low-bank-1..... It said this can be caused by Catalytic converter defective, or engine misfire or running condition, or large vacum leak, or engineoil leakeage into exhaust-valve guide seals piston rings....MY boy suggested I just do a tune up....Changing plugs and wires etc...What do you guys think?? anyone with similar problems??? I have an 01 2.8 quattro Automatic....


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## Massboykie (Aug 15, 2006)

*Re: Check engine code P0420??? (queensfinest)*

Hey Queens 
All of those could cause that error, but you would be better off getting the codes read with a VAG-COM.
Do you know someone that has one? You can buy them of eBay now for around $40 shipped and all you would need then is the Ross-tech software. Or you can buy the original which comes with the software and support etc... (http://www.ross-tech.com) 
Just an FYI
Cheers
Massboykie


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## queensfinest (Aug 11, 2006)

*Re: Check engine code P0420??? (Massboykie)*

Nah I unfortunately don't have that tool...I do have a boy that works for one of the local VW/Honda dealerships in Tampa as a tech, maybe I should holla at him before I start financing my own tune up.....


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## Massboykie (Aug 15, 2006)

*Re: Check engine code P0420??? (queensfinest)*

Hey Queens
Yeah, definitely. Why throw money after a tuneup if it's not necessary.
If you intend to tinker with the car in the future a VAG-COM will pay for iteslf in spades. Well worth it.
Cheers
Massboykie


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## ryan mills (May 3, 2002)

Plugwires would be quite hard on a car that doesn't have them. Your catalytic converter is showing it's age. If you don't want to go through the hassle of buying a new cat and oxygen sensors, just go here: http://www.42draftdesigns.com/faq.htm#test and look under this: "Is there anything I can do to avoid the CEL?" Works every time, and for $35 you can't go wrong.


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## CE (Jan 21, 2001)

*Re: Check engine code P0420??? (queensfinest)*

Just reset the check engine, could be nothing, work from the simple stuff, before thinking major calamity. i use the Ross Tech works great, simple, My VR-6 Jetta has the coil issue arcing, when it really damp cold, check engine will come on goes out after few days, or i jsut reset it, always mis fire #5, no biggy, even a bad tank of gas will cause issues, reset it and fdrive, if it keeps coming back on, then let a dealer look at it


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## Massboykie (Aug 15, 2006)

*Re: Check engine code P0420??? (queensfinest)*

Hey Queens
CE has a point, reset it and see if it comes back. Look into getting access to t VGA-COM when it does.
Cheers
Massboykie


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## QUEENS718 (Mar 15, 2007)

*Re: Check engine code P0420??? (Massboykie)*

I'm queensfinest by the way, but when I had the code checked at auto zone he also cleared it.... That was last thursday and the check engine light has not come back on....I called audi and they said it would be $105.00 to verify if somethings wrong, but the Cat is covered up to 80,000 miles...


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## Massboykie (Aug 15, 2006)

*Re: Check engine code P0420??? (QUEENS718)*

Hey QueensFinest
I think most of the emmisions related stuff is covered under that same warrantee. This is a federal requirement I believe. O2 sensors, Cats, even throttle bodies... It also does not matter if you bought the car form Audi or not, as far as I know.
You should be safe to take it in and have them check it out.
Cheers
Massboykie


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