P0420 code
Thread Starter
On The Tree
Joined: Feb 2002
Posts: 105
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From: IL
P0420 code I had my car scanned in the spring and this is the code it threw,cleared the code but it came right back. So i swapped the o2 sensors disconnected the battery and the car was fine for about 500 miles. Today the code came back. I have headers with a catted y pipe. From what I have read it is either the o2 sensors or one of the cats is bad any thoughts on what it might be?
po420 is a catalyst effecient to low code What it means is that your catalytic converter is no longer doing what it is supposed to within the maragins that the government has set for legal emissions. Being as you have a 01 TA it should be covered under the converter warranty 8yrs 80,000 miles unless you have exhausted one of these. There are a few ways to tes and see if that is what it is but taking it to the dealer and telling them that it is setting a noneffecient converter code is the easiest thing to do. The other thing you could do is a vacuum test. Or if you knew which one change your downstream o2's around, clear the code and see if th code comes on again. if it does then it is the cat. If you want more info on the vacuum test way let me know and I'll post it also
Good luck,
..RJ..
Good luck,
..RJ..
TECH Fanatic
Joined: Mar 2004
Posts: 1,017
Likes: 0
From: Laguna Niguel, CA
I would like to know how to vaccuum test it. I am also throwing a p0420 and p0430 code with my new MAC header install. There may be a leak somewhere up stream, and I dont want to have to buy new cats it it is just a leak....
Originally Posted by gun5l1ng3r
I would like to know how to vaccuum test it. I am also throwing a p0420 and p0430 code with my new MAC header install. There may be a leak somewhere up stream, and I dont want to have to buy new cats it it is just a leak....
Here is an excellent article that shows the O2 sensor output for these DTC failures.
Originally Posted by JPWS6
I have aftermarket high flow cats with my headers. So the P0420 or P0420 code is common with high flow cats?
