SES Light - P0420 and P0430..NEED HELP!!
08-29-2006, 10:56 PM
#1
On The Tree
Thread Starter
iTrader: (1)
Join Date: Jan 2003
Location: Western Ma
Posts: 112
Likes: 0
Received 0 Likes
on
0 Posts
So...Do I need to replace O2 sensors or are my cats gone?? NEED HELP!! Hello all!! Taking a drive today and got a SES light. 
Took car to my mechanic and I'm throwing a P0420 and P0430. He was nice enough to print off the service info. for the codes and he told me it looks like I need to replace the cats. 
Now...I have some questions. (I know there are a bunch of gurus in this area out there. Please chime in.....)
Is it possible that I have an O2 sensor problem and the cats are ok? (No signs of physical damaged to cats, but car has 94,XXX on the clock)
If so, Can I do anything on my own to troubleshoot?
If not, I'll be looking for some High Flow cats that will bolt up to the stock exhaust manifolds. Won't be doing headers or y-pipe anytime soon. Any suggestions??
Thanks in advance!! I truly appreciate any input!!
Took car to my mechanic and I'm throwing a P0420 and P0430. He was nice enough to print off the service info. for the codes and he told me it looks like I need to replace the cats. Now...I have some questions. (I know there are a bunch of gurus in this area out there. Please chime in.....)
Is it possible that I have an O2 sensor problem and the cats are ok? (No signs of physical damaged to cats, but car has 94,XXX on the clock)
If so, Can I do anything on my own to troubleshoot?
If not, I'll be looking for some High Flow cats that will bolt up to the stock exhaust manifolds. Won't be doing headers or y-pipe anytime soon. Any suggestions??
Thanks in advance!! I truly appreciate any input!!
Last edited by ModGod; 08-30-2006 at 07:17 AM.
08-30-2006, 12:00 AM
#3
TECH Fanatic
iTrader: (1)
Join Date: Apr 2006
Location: Edgewater, MD
Posts: 1,507
Likes: 0
Received 0 Likes
on
0 Posts
i had PO420 pop up recently and i told the man to change the cats and he convinced me that it was prolly O2's so i let him replace them, got the car back and the ses light was off.........for a few days. SHoulda replaced the cats. Im not sure what to do about the other code though. Hope that helps a little bit
08-30-2006, 07:25 AM
#5
On The Tree
Thread Starter
iTrader: (1)
Join Date: Jan 2003
Location: Western Ma
Posts: 112
Likes: 0
Received 0 Likes
on
0 Posts
I know the stock manifolds are 2 1/4". Does anyone have the 2 1/4" Random Technology high flow cats?? (part number: 13-181-22000 - Random Technology 2.25" inlet/outlet, 11.5" long, Replacement High-Flow Catalytic Converter?? Are they direct bolt-on to the stock manifolds or will I need to patch weld pieces?? I'm deciding between those cats and the entire high flow cat/ y pipe piece from Random Tech. It's quite a bit more expensive but I'm sure it bolts right up, based on the pics. Any ideas?
08-30-2006, 06:12 PM
#6
12 Second Club
iTrader: (7)
Join Date: Jul 2005
Location: La Plata Maryland
Posts: 275
Likes: 0
Received 0 Likes
on
0 Posts
P0420 - Catalyst system efficiency below threshold, left bank
P0430 - Catalyst system efficiency below threshold, right bank
If your mechanic already cleared your light out, I would wait and see if it comes back on. A lot of the time exhaust and 02's through codes for stupid reasons and never come back on. If it does come back on it probably is your cats. I know you said you didnt want to do headers or y-pipe but for the 300 your probably going to spend on high flow cats, thats a good chunck towards very nice set-up. Hope this helps!
P0430 - Catalyst system efficiency below threshold, right bank
If your mechanic already cleared your light out, I would wait and see if it comes back on. A lot of the time exhaust and 02's through codes for stupid reasons and never come back on. If it does come back on it probably is your cats. I know you said you didnt want to do headers or y-pipe but for the 300 your probably going to spend on high flow cats, thats a good chunck towards very nice set-up. Hope this helps!
08-30-2006, 10:27 PM
#7
hey man just had the same prob on my car i see it alot with GM's cat's. This is what needs to be done. you need to get ahold of someone that has a scanner. not just a code reader/grabber jobby. i am talking like a otc genisys or modis/solus. they will be able to watch the o2's. upon watching them, just make sure that they fluctuate rapidly. if they are, your o2s' are working. 99.9% of the time those two codes mean you need new cat's. i would check aftermarket exhaust as a start due to the fact you can start a nice setup with the money your going to pay for the stock cats.
Trending Topics
08-30-2006, 10:41 PM
#8
On The Tree
Thread Starter
iTrader: (1)
Join Date: Jan 2003
Location: Western Ma
Posts: 112
Likes: 0
Received 0 Likes
on
0 Posts
Hi!!! Thanks for the insight and ideas. My cousin is a tech for a Chevrolet dealership in my area and owns a scanner. I'll pay him a visit and monitor O2 sensors to make sure they're still alive. If so, then it's time for my first major upgrade to the SS. Thanks again..... 
08-30-2006, 10:45 PM
#9
^Agree with everything above. I'll only add that the first time it happened to me, I had the code turned off and it went a year without reappearing. Then it came back and kept coming back and I had to have the cat replaced. So you might just get them turned off and see what happens.
08-31-2006, 05:31 AM
#10
TECH Resident
iTrader: (2)
Join Date: Jul 2002
Location: Richmond, VA
Posts: 885
Likes: 0
Received 0 Likes
on
0 Posts
I have a p0420 and kept coming back on. I know its the cat because the o2's are new and now the car loses power and revs up to 3500-4k on the highway. Going to gut the cats until I can afford to put in LT's and o/r Y.
08-31-2006, 09:18 AM
#12
On The Tree
Thread Starter
iTrader: (1)
Join Date: Jan 2003
Location: Western Ma
Posts: 112
Likes: 0
Received 0 Likes
on
0 Posts
Unfortunately, it's got a Rejection sticker. I've only had the car about a month or so, and I tried to get a sticker a couple weeks ago. I want to buy the parts (just catted y or headers and catted y) and go directly to the shop that's doing the work. It's pissing me off because everywhere I drive it I feel like I'm eluding the police....lol
08-31-2006, 12:27 PM
#13
Banned
iTrader: (2)
Join Date: Jul 2006
Location: San Antonio, TX
Posts: 201
Likes: 0
Received 0 Likes
on
0 Posts
Dude! How Many Miles Do You Have On Your Vehicle? I Had The Same Problem...concerning Your Mileage I Only Ask As Cats Are Covered By Federal Law To Meet Certain Mileage Restrictions On Vehicles....period....no Do I Have A Warranty Or Ext Warranty....they Must Must Must Meet A Certain Mileage Or The Dealership Will Have To Replace For Free....i Almost Paid $200 For A Stocker To Go Back In...and Was So Pissed Cause I Just Like You Had Just Purchased The Vehicle. I Didn't Have The Doh For The Dual Setup I Wanted Then Found Out From A Gm Tech On Here How To Solve My Issue...go To Gm And Get A Free One!!!! So Call A Service Drive Tech. And Give Him Your Specs. You Never Know! Actually You Can Find Out Real Quick If The Cat Is Backed Up Or Packed With Junk...just Take A Laser Temp. Gauge And Point It Before The Cat And After The Cat. Mine Was Like 300' Before And 600' After...while The Otherside Was 300' Before And 200' After. The Exhaust Should Get Cooler On The Outlet Side Of The Exhaust. Hope That Helps Temporarily...i'm Still Saving For That Non Cat True Dual Setup!
08-31-2006, 08:36 PM
#14
On The Tree
Thread Starter
iTrader: (1)
Join Date: Jan 2003
Location: Western Ma
Posts: 112
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Cantalope Kid
Dude! How Many Miles Do You Have On Your Vehicle? I Had The Same Problem...concerning Your Mileage I Only Ask As Cats Are Covered By Federal Law To Meet Certain Mileage Restrictions On Vehicles....period....no Do I Have A Warranty Or Ext Warranty....they Must Must Must Meet A Certain Mileage Or The Dealership Will Have To Replace For Free....i Almost Paid $200 For A Stocker To Go Back In...and Was So Pissed Cause I Just Like You Had Just Purchased The Vehicle. I Didn't Have The Doh For The Dual Setup I Wanted Then Found Out From A Gm Tech On Here How To Solve My Issue...go To Gm And Get A Free One!!!! So Call A Service Drive Tech. And Give Him Your Specs. You Never Know! Actually You Can Find Out Real Quick If The Cat Is Backed Up Or Packed With Junk...just Take A Laser Temp. Gauge And Point It Before The Cat And After The Cat. Mine Was Like 300' Before And 600' After...while The Otherside Was 300' Before And 200' After. The Exhaust Should Get Cooler On The Outlet Side Of The Exhaust. Hope That Helps Temporarily...i'm Still Saving For That Non Cat True Dual Setup!
Hi, thanks for the reply. My car has 94,000 miles and I think the warrantee covers up to 80,000 miles. Thanks anyway!!! Any other thoughts anyone??
09-01-2006, 10:02 PM
#15
On The Tree
Thread Starter
iTrader: (1)
Join Date: Jan 2003
Location: Western Ma
Posts: 112
Likes: 0
Received 0 Likes
on
0 Posts
to the top
Originally Posted by ModGod
Hi, thanks for the reply. My car has 94,000 miles and I think the warrantee covers up to 80,000 miles. Thanks anyway!!! Any other thoughts anyone??
