S2000 Under The Hood S2000 Technical and Mechanical discussions.

P0420 code

Thread Tools
 
Old Sep 17, 2025 | 04:15 PM
  #1  
jchau123's Avatar
Thread Starter
Registered User
5 Year Member
Photogenic
Liked
 
Joined: Apr 2018
Posts: 73
Likes: 5
Default P0420 code




CEL came on today. Went to autozone pulled p0420.

Thoughts on this direct fit cat converter to fix p0420 code? Cost $130

Or should i get a spacer? its 8$ and no drilling required right?

Last edited by jchau123; Sep 17, 2025 at 04:20 PM.
Reply
Old Sep 18, 2025 | 04:42 AM
  #2  
Chuck S's Avatar
Member (Premium)
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Jul 2014
Posts: 13,786
Likes: 1,536
From: Chesterfield VA
Default

Do you need to pass smog with a visual inspection? The spacer may not work in that case but otherwise do whatever it takes.

For eight bucks -- the cost of a Big Mac Meal -- why not try the spacer? You can always fit a replacement cat. While you're under the car spray all the bolt threads with PB Blaster and let them soak in case you need to pull the cat later.

-- Chuck
Reply
Old Sep 18, 2025 | 01:24 PM
  #3  
engifineer's Avatar
Moderator
10 Year Member
Community Builder
Liked
Loved
 
Joined: May 2014
Posts: 7,836
Likes: 2,438
Default

Take your cat off the car, see if the media moves around or rattles when you shake it. Typical way they fail. You may even see loose media in there when you remove it if it is going bad. If the Cat is actually getting plugged you really want to address that vs just using the defouler trick.

But for reference, if doing the defouler trick you want 2 of them. Drill the small hole out to the diameter of the inside of the defouler on one, then screw that one into the other defouler, then screw into the test pipe, hollowed out cat, etc One may not be enough to fool the system.

You can use the defouler though as a cheap way to see if the sensor is just bad. Most times the 2 defouler trick will work even with a test pipe so if the light comes back on you may have a bad secondary sensor instead of a bad cat.
Reply
Old Nov 3, 2025 | 06:13 PM
  #4  
jchau123's Avatar
Thread Starter
Registered User
5 Year Member
Photogenic
Liked
 
Joined: Apr 2018
Posts: 73
Likes: 5
Default

Sorry to bring this back up. But the inside of the cat moves around and is no longer good; snapped my o2 sensor

I currently have a hks hi power exhaust.

Not sure about a used oem or the ebay cat.
Thinking about a high flow cat.

Any suggestions im seeing a lot people mention berk and am i okay without a tune for the hfc?

Last edited by jchau123; Nov 3, 2025 at 06:31 PM.
Reply
Old Nov 4, 2025 | 01:03 AM
  #5  
JBamin's Avatar
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2016
Posts: 316
Likes: 76
From: Ohio
Default

you can use a berk HF cat on an hks hi power and not necessitate a tune. Many of us out here doing it.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
El S2000
S2000 Engine Management
4
Mar 8, 2014 02:05 PM
arins2k
S2000 Under The Hood
11
Apr 22, 2010 07:10 PM
ryanfeldman
S2000 Under The Hood
9
Aug 17, 2009 07:46 AM




All times are GMT -8. The time now is 08:07 PM.