Code #P0421. Please help.

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#21

03-13-2010, 12:49 AM

hauptjr

1st Gear

Join Date: Feb 2010

Location: Pittsburgh, PA

Posts: 125

Quote:

Originally Posted by john@astigracing.com

Sorry for the late reply guys.

The code IS BACK. I'll try to check the vacuum lines behind each head for the Kombi Valves, and if that doesn't work, I'll check the wastegate.
Jim-- Do you think you can point out to me where this wastegate is located?

Appreciate it!

any luck yet? Is the CEL still coming on? Is it still throwing a p0420?
thanks!

#22

03-29-2011, 12:08 PM

stllplyswcars

1st Gear

Join Date: Mar 2011

Posts: 1

Same issue

Has there been any progress regarding this issue. I have the same thing going on with my 02 A4 3.0, and poking around the engine compartment looking for a vacuum leak I found a really loose hoseclamp, I tightened it and I cleared the code with my scanner so we will see if it comes back. i would hate to spend any money if it could be a split or torn vacuum line.

#23

04-07-2011, 10:44 AM

Theugly02

1st Gear

Join Date: Apr 2011

Location: Chicago

Posts: 1

Is there an aftermarket catalytic converter that is cheaper than the oem Audi ?

#24

01-12-2014, 04:54 PM

cwilson

1st Gear

Join Date: Jan 2014

Posts: 4

I know this is an old thread but I am having this same issue with my 02 a4 3.0 quattro (97000 miles). I'm looking for some insight as to how you made out with this code