Go Back > Audi Models > Audi A4 > B6 Models
Sign in using an external account
Register Forgot Password?

B6 Models Please discuss all 2002 - 2005 B6 A4 topics here...

Welcome to Audi Forums!
Welcome to Audi Forums,

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

LinkBack Thread Tools Search this Thread
Old 09-02-2009, 08:59 PM
1st Gear
Join Date: Sep 2009
Posts: 6
Default Fault Code P0420 (cat converter)

Yesterday, the wife's '02 A4 3.0 Quattro Manual (89K) got a CEL with the dreaded fault code P0420 (cat converter efficiency below threshold). My independent Audi mechanic cleared the code, but cautioned that I would likely get it again. He said that the tolerances in the control module are programmed too tightly, and the ECM throws the code at the slightest variance in O2 readings behind the cat. Says he has seen cats replaced under warranty in response to this fault code, only to have the code reappear within a year or so. Audi, so far, hasn't developed a new flash program with looser tolerances.

I love the car, but hate the problems and repair expense. I'll trade the thing before I start down the slippery slope of cat-converter replacements! That is, unless someone out there has a solution.

Last edited by silverghost; 09-03-2009 at 08:47 AM.
Old 09-02-2009, 08:59 PM

03, 30, a4, audi, cel, code, codes, conversion, converter, engine, fault, number, p0420, trouble, tt

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Featured Sponsors
Vendor Directory
New Sponsors

All times are GMT -4. The time now is 10:01 PM.

Internet Brands, Inc.
Emails Backup