Is P0421 a persistant code? - Audi Forums
Audi Forum Audi Forum

Auto Insurance

» Featured Product
Wheel & Tire Center

Go Back   Audi Forums > Audi Models > Audi A4, RS4 and S4 Forum > B5 Forum
Register Home Forums Active Topics Gallery / Showroom Auto Loans Garage Search Today's Posts Mark Forums Read Auto Escrow

B5 Forum 1996-2001.5 Audi A4 / 2000-2002 Audi S4 & Audi RS4. (Audi A4 Forum, Audi S4 Forum, Audi RS4 Forum)

Audi-Forums.com is the premier Audi Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 05-26-2010, 03:44 PM   #1 (permalink)
Newbie
 
Join Date: Nov 2009
Posts: 3
Gallery: (0)
ayjay1975 is on a distinguished road
Cool Is P0421 a persistant code?

My s4 keeps turning on the servie engine light with a p0421 code. I have captured the live data for the O2 sensors and graphed them and found the lines to run paralell. (Leading me to believe both O2 sensors are operating pretty close to the same and that it is not an O2 Sensor issue, but rather a problem with the cat.) My question is, will the light eventually go off on it's own after a period of time? I know my A8 will throw occasional codes but eventually the service light goes out even though the codes are still present. I haven't driven the car long enough with the light on to see if it will go out on it's own.

Any advice appreciated.
ayjay1975 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 05-28-2010, 01:36 PM   #2 (permalink)
Senior
 
Join Date: Apr 2010
Posts: 220
Gallery: (0)
Pete@ecstuning is on a distinguished road
Default

Warm up catylist below efficiency - that should not go out unless the problem does not come back. Likely, you're looking at a new catalytic converter. Any other cat related codes? How frequently does the error come back?
Pete@ecstuning is offline   Reply With Quote
Old 06-01-2010, 09:15 AM   #3 (permalink)
Newbie
 
Join Date: Nov 2009
Posts: 3
Gallery: (0)
ayjay1975 is on a distinguished road
Default

Thank you for the reply. I have only had the car for a few months and that code has come up 2 times. No other codes at this time. Currently my ecuis at APR having a look over. It want down and would no longer run the car. I am running a used stock ECU at the moment and the problem hasn't come back YET. I am wondering if the tolerances set on my chipped ecu were too tight?

I see you work for ESC tuning... I lost the little ESC logo that fits inthe top on my short throw shifter. Any ideas on how to get a replacement? (It looks silly without it)

Thanks again!
ayjay1975 is offline   Reply With Quote
Old 06-01-2010, 03:11 PM   #4 (permalink)
Senior
 
Join Date: Apr 2010
Posts: 220
Gallery: (0)
Pete@ecstuning is on a distinguished road
Default

Do you have a part number for the shifter you've got from us?
Pete@ecstuning is offline   Reply With Quote
Old 06-01-2010, 11:23 PM   #5 (permalink)
Full Member
 
Join Date: Jul 2009
Location: lowell,mass
Posts: 128
Gallery: (0)
pauly b is on a distinguished road
Default 0421/0431 + secondary air

I know thats a hose throwing these codes. But i'm ready to up grade any way. Price cats/dp's i'm in the boston area ??
pauly b is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

  Audi Forums > Audi Models > Audi A4, RS4 and S4 Forum > B5 Forum


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

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


Powered by vBadvanced CMPS v3.2.2

All times are GMT -5. The time now is 05:12 AM.




Garage Plus vBulletin Plugins by Drive Thru Online, Inc.

Content Relevant URLs by vBSEO 3.3.2