P0420 Fix

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Oct 23, 2018 | 03:44 PM

#31

B serious

Joined: Nov 2007

Posts: 8,841

Likes: 1,705

From: Illnoise. WAY downtown, jerky.

Quote:

Originally Posted by attar84

I'm sorry to bring this from the dead, but I'm having a similar issue. I replaced my cat with a brand new one from JCWhitney, it was fine for a few months but CEL is back again with the P0420. I took the cat out again, shook it a little, not rattling, everything looks intact, no weird smells either. I tried the spark plug spacer, engine light still won't go away. I don't know what else it could be. Please help!

You're using an aftermarket cat.

You should expect a P0420.

Use an O2 spacer like people do on test pipes.

Oct 23, 2018 | 03:45 PM

#32

B serious

Joined: Nov 2007

Posts: 8,841

Likes: 1,705

From: Illnoise. WAY downtown, jerky.

Quote:

Originally Posted by attar84

ok well I just took it to autozone to pull the codes again..now it's P2270 O2 Sensor Signal Stuck Lean Bank 1 Sensor 2. This is new so I'm wondering if it's because of the 2 non-foulers I have installed there.

And P0420 isn't there anymore, but maybe it'll come back once I address this issue.

Use no spacer...see if that fixes it.

If P0420 turns back on, go to 1 spacer.

Or buy an OEM cat and use no spacer.

Oct 23, 2018 | 04:58 PM

#33

summitrider2012

Joined: Sep 2012

Posts: 505

Likes: 7

An p0420 is a cat inaficient cat code and usually leads to a faulty cat. Mine went just under 8/80 and I got it replaced under warranty with new sensors due to it damages the secondary o2 sensor when the cat broke

Oct 29, 2018 | 05:29 AM

#34

attar84

Registered User

Joined: Mar 2011

Posts: 14

Likes: 0

So after I discovered the P2270, I had the codes erased. I drove for about a week, checked again with my obd scanner, no codes and all tests are complete. I got it inspected and it PASSED with NO issues!

I did not change or remove the non-foulers, I did not install the 90-degree spacer even though I just got it in the mail. I do not know how long before I get that engine light back, I hope I don't, but at least I can get my registration done now.

Thank you everyone here for your help! Truly appreciated!