P0420 Just threw that code, bad cat?
#1
On The Tree
Thread Starter
iTrader: (4)
Join Date: Jun 2006
Posts: 171
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Well I just threw a P0420 code on my 00 WS6. I am the original owner and I have only 20k miles on the car. Assuming I double check first if its the 02 sensor, do you think the dealer will replace the cat if its bad? I have borla y-pipe and exhaust done but thats it. How should I approach them if I bring the car in for service, cause I dont want to pay to swap oxygen sensors if its the cat!
#2
FormerVendor
iTrader: (3)
Join Date: Aug 2002
Location: Albany, New York
Posts: 622
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
That code is for a insufficient catalyst. If the stock cat is bad it still should be covered under the emission warranty up to at least 50K.
Many times with headers its not unusual to get that code.
Many times with headers its not unusual to get that code.
#3
On The Tree
Thread Starter
iTrader: (4)
Join Date: Jun 2006
Posts: 171
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
No headers here just borla y-pipe and exhaust, I dont want to go to the dealer and have them pull some crap that its the oxygen sensor and pay for that then find out later to get the same code.
#4
TECH Senior Member
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
You could swap your rear 02's side to side and see if the code changes to P0430. Don't think they'll hassle you for your exhaust as long as they can bolt in a new cat. I know a couple people that had their's replaced free w/catbacks. Over the phone they got the "Might be an 02, have to charge a diagnostic fee, etc." but once they condemned the cat there was no charge.
#6
On The Tree
Thread Starter
iTrader: (4)
Join Date: Jun 2006
Posts: 171
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by 2001NBMZ28
You could swap your rear 02's side to side and see if the code changes to P0430. Don't think they'll hassle you for your exhaust as long as they can bolt in a new cat. I know a couple people that had their's replaced free w/catbacks. Over the phone they got the "Might be an 02, have to charge a diagnostic fee, etc." but once they condemned the cat there was no charge.
If it changes to P0430 does that mean its the oxygen sensor?
#7
TECH Senior Member
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Yep, clear any codes after the swap. If you get P0420 again should be the cat. Personally I wouldn't bother swapping them, it's most likely the cat - just something you can do to make sure it's not the sensor.
Trending Topics
#8
Pontiacerator
iTrader: (12)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by 2001NBMZ28
Yep, clear any codes after the swap. If you get P0420 again should be the cat. Personally I wouldn't bother swapping them, it's most likely the cat - just something you can do to make sure it's not the sensor.
#9
TECH Enthusiast
Join Date: Jul 2006
Location: San Diego
Posts: 638
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Bad O2 sensor won't cause code to move side to side. The code sets because the computer sees too much activity after the cat, ie. the front and rear O2 sensors are switching at the same rate. If the sensor is bad it will set a differant code.
#10
TECH Veteran
iTrader: (1)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
My Silverado started throwing that code. At 120k miles, I put on Dynatech headers and hi flow cats. At 200k miles that code started popping up on gas I bought in Alabama and Texas. Now at 211k miles, that code comes up on gas in Georgia as well. I don't feel like buying cats, so I'm just going to tune out the ses for that code.
#15
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Originally Posted by CapoWS6
Update: dealer replaced my cat for free today!!
![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
Glad you got it taken care of!