PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

P0420 Catalyst System Efficiency Below Threshold (Bank 1)

Thread Tools
 
Search this Thread
 
Old Dec 5, 2005 | 11:06 AM
  #1  
SPL's Avatar
SPL
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Nov 2005
Posts: 98
Likes: 1
From: Burleson, TX
Default P0420 Catalyst System Efficiency Below Threshold (Bank 1)

I took my car to autozone to get my SES scanned. This is the code they showed up. He said it was probably an o2 sensor but wasn't sure. Do I need new o2 sensors? Is this code hurting my performance? I have to get it fixed anyway since my inspection is due this month...
Reply
Old Dec 5, 2005 | 11:41 AM
  #2  
BrandonDrecksage's Avatar
TECH Fanatic
iTrader: (1)
 
Joined: Mar 2005
Posts: 1,688
Likes: 0
From: Central jersey, nj
Default

Originally Posted by SPL
I took my car to autozone to get my SES scanned. This is the code they showed up. He said it was probably an o2 sensor but wasn't sure. Do I need new o2 sensors? Is this code hurting my performance? I have to get it fixed anyway since my inspection is due this month...
it means your cat is gone...how many miles do you have? gm has to replace it udner the 8years or 80k miles if your below that.
Reply
Old Dec 5, 2005 | 11:44 AM
  #3  
SPL's Avatar
SPL
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Nov 2005
Posts: 98
Likes: 1
From: Burleson, TX
Default

I have 54000 miles and it's a 2001. I don't have any type of warranty. Do you mean they will replace it for free?
Reply
Old Dec 5, 2005 | 11:54 AM
  #4  
98redorangeta's Avatar
12 Second Club
iTrader: (10)
 
Joined: Sep 2005
Posts: 948
Likes: 0
From: From Ohio now in that state up north
Default

I am assuming you are stock If not that could be your problem. However with 54000 on a 2001 i would be willing to bet that it is a rear O2 try swaping them and see if it goes to the other bank. If it still is on the same bank then your cat is dead and on something emmisions related like that i think they would have to replace it for free its not an extended warenty thing.
Reply
Old Dec 5, 2005 | 12:06 PM
  #5  
92SilverSHO's Avatar
TECH Fanatic
iTrader: (3)
 
Joined: Mar 2003
Posts: 1,162
Likes: 0
From: Bensalem, Pa, now montreal, Quebec
Default

i doubt its an o2, if it was, it would probably show a bad o2 sensor, not a bad cat code, they tried that crap with me, they just dont like replacing crap under warranty. after the cat was replaced, no more light
Reply
Old Dec 5, 2005 | 12:13 PM
  #6  
2001NBMZ28's Avatar
TECH Senior Member
 
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
Default

Most likely a bad driver's side cat - they're covered under the federal emissions warranty for 8yrs/80K. There's pages of threads in the PCM Diag & Tuning forum, search there for "P0420" I know 2 people that had theirs replaced free.
Reply
Old Dec 5, 2005 | 10:22 PM
  #7  
RevGTO's Avatar
Pontiacerator
20 Year Member
Photogenic
Liked
Loved
iTrader: (12)
 
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
Default

Just get it cleared and see if it comes back. I had that code come up one day as I was lugging my car around (I had an older guy as a passenger and was tying to keep it quiet). I had it cleared, used some fuel injector cleaner in my next tank of gas, and it hasn't returned - been about four months.
Reply
Old Dec 6, 2005 | 06:42 AM
  #8  
King James's Avatar
TECH Resident
iTrader: (13)
 
Joined: Feb 2004
Posts: 838
Likes: 0
From: Terre Haute, IN
Default

Had the same code on my 2001 with 68k miles and no warrenty. Took it to a dealership and they replaced both cats for free.
Reply
Old Dec 6, 2005 | 10:07 AM
  #9  
slowpoke96z28's Avatar
TECH Addict
15 Year Member
iTrader: (2)
 
Joined: May 2005
Posts: 2,099
Likes: 9
From: cedar hill, tx
Default

cars come from the factory with 8 year / 80,000 mile emission system warranty. its a federally mandated deal that all manufacturers that sell cars in America have to honor. its totally seperate from the bumper to bumper and/or powertrain warranties. if you switch rear O2s from side to side and the code stays on the driver side, GM gets to give you a new catalytic converter. and this problem won't affect engine performance.
Reply
Old Dec 6, 2005 | 11:42 AM
  #10  
SPL's Avatar
SPL
Thread Starter
Staging Lane
iTrader: (1)
 
Joined: Nov 2005
Posts: 98
Likes: 1
From: Burleson, TX
Default

I'm taking it in the morning to the dealership to have the cat replaced. Could they deny the warranty if I have a lid?
Reply
Old Dec 6, 2005 | 11:55 AM
  #11  
2001NBMZ28's Avatar
TECH Senior Member
 
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
Default

Lid is fine - put a paper filter in though if you're running an oiled filter - one of their favorite excuses.
Reply
Old Dec 6, 2005 | 03:56 PM
  #12  
BrandonDrecksage's Avatar
TECH Fanatic
iTrader: (1)
 
Joined: Mar 2005
Posts: 1,688
Likes: 0
From: Central jersey, nj
Default

Originally Posted by SPL
I'm taking it in the morning to the dealership to have the cat replaced. Could they deny the warranty if I have a lid?
no...cause it has nothing to do with the cats going bad.

my first went out at 51k..second at 56k..both replaced for free because of the warranty.
Reply
Old Dec 6, 2005 | 06:59 PM
  #13  
Kyle C's Avatar
Staging Lane
 
Joined: Mar 2004
Posts: 87
Likes: 0
From: Sanford NC
Default

Same code here at 50K, they replaced one of the cats no charge.
Reply
Old Dec 6, 2005 | 07:35 PM
  #14  
blu02ss's Avatar
Teching In
iTrader: (3)
 
Joined: Aug 2005
Posts: 37
Likes: 0
From: Houston, Tx
Default

Just take it to a dealership and get your pass side cat replaced.
Reply
Old Dec 7, 2005 | 12:42 AM
  #15  
brandon1221's Avatar
Launching!
iTrader: (8)
 
Joined: Aug 2003
Posts: 287
Likes: 0
From: North Carolina
Default

i had the same code on my 00 trans am. It was the cat, however since i have headers(even though they are shorty) it voided the warrenty they said, so i just bought a stock cat off someone for $30 and the car works fine now.
Reply
Old Dec 19, 2005 | 09:27 PM
  #16  
TigerWoodsJr's Avatar
On The Tree
 
Joined: Mar 2004
Posts: 190
Likes: 0
From: Maine
Default

ok... my cel came on with the same code. I have 64k on the car, I don't have a cat off the end of the Y pipe... but are those cats that are built onto the stock exhaust manifolds that look like little boxs? my cars gas mileage has gone down pretty steadily the past few weeks before this SES came on.... I just filled up at 12.8 today... thats WAY off my 16 I used to get... and 14 is the worst previous with serious racing, none on this tank. I have had the car for 20k miles with no cat at the y pipe... 01 btw... and it has never thrown a cel.. I figured it was my o2's due to the poor gas mileage but you guys don't seem to think so?
Reply
Old Dec 20, 2005 | 11:50 AM
  #17  
napoleon's Avatar
Staging Lane
iTrader: (3)
 
Joined: Dec 2004
Posts: 83
Likes: 0
Default

i wouldnt think it weird to have either the 02 or the cat go out. At 60K our car was throwing CELs for a malf. cat too. This is when the car was as stock as yours. I would start there and if that doesnt work, i would go immediatly to the 02s.
Reply




All times are GMT -5. The time now is 03:08 AM.