How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask OnlineMechanic Your Own Question
OnlineMechanic
OnlineMechanic, Mechanic
Category: Audi
Satisfied Customers: 3423
Experience:  3 years Autozone Manager, 10 years Mechanic
9051600
Type Your Audi Question Here...
OnlineMechanic is online now
A new question is answered every 9 seconds

Audi fault code p0431 & p0421. Rich air/fuel ratio, cat efficiency

Resolved Question:

Audi fault code p0431 & p0421. Rich air/fuel ratio, cat efficiency below threshold, faulty cat converter, leak before cat converter, etc... Car runs fine. Rumor has it the "check eng light" limits are set too tight.
Is there some way to fix with thing without breaking the bank?
2001 Audi alroad 2.7t
Submitted: 7 years ago.
Category: Audi
Expert:  OnlineMechanic replied 7 years ago.

Hello and thank you for choosing Just Answer.

 

The best way to get around this is to use "oxygen sensor stimulators" . These are actually the Non-foulers for the spark plugs. What this will do is move the oxygen sensors further away from the exhaust stream and give the computer a good reading. This is what most people do. Here is what they look like:

 

 

All you do is screw the oxygen sensor into the non-fouler and then screw it into the exhaust. Then reset the light and that should solve your issue.

 

Customer: replied 7 years ago.
O2 sensor stimulators. Got it.
Problem is I have no idea where or what the "non-fouler" is.Where it is located or looks like. If I go to a non-dealer mechanic with these in hand how detailed is the fix?
Thanks
Expert:  OnlineMechanic replied 7 years ago.
You can buy them at any store and do the repairs yourself or take it in to any mechanic they will know what to do.
Here is what they look like:


You will screw the oxygen sensor into the non-fouler and then into the exhaust. Here is what it will look like:
//f01.justanswer.com/ref/http_img139.imageshack.us/img139/2154/214218ug.jpg


Edited by OnlineMechanic on 3/20/2010 at 10:14 PM EST
OnlineMechanic and other Audi Specialists are ready to help you