p0422 Main catalyst below threshold error
I have a 1998 VW Jetta GLX VR6 and am having trouble clearing the p0422 01 error.
The first thing i tried was i replaced the catalytic converter, front o2 sensor and rear o2 sensor. I then cleared the error and drove on the car for about 25 - 30 mile and the error returned. I just put a spark plug non-fouler spacer in hoping that it will help clear the error (maybe it related to a different cat? The new cat is nothing special so i figured it wouldnt be a problem). I also tried clearing the computer by unhooking the battery for a couple hours.
I have two questions really. The first one is whether i should drill out the hole on the non-fouler to 1/2''. I drilled it out but left the 1/4'' hole at the end because i wasnt sure. Should i have drilled it 1/2'' all the way through?
Second question, is there anything else i can do to diagnose the problem? what sort of other components could be throwing the p0422 error?
Any help on this would be helpful i have done all that i can think of to clear the error but to no avail.
EDIT: I put the non-fouler on the rear o2 sensor. There are two o2 sensors in this setup, one pre cat and one post cat.
Last edited by sumone4life; 07-08-2009 at 06:30 AM.