How To Clear Code? P0420?
Thread Starter
Melting Slicks
Joined: Mar 2005
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From: Palm beach Florida
St. Jude Donor '05-'06-'07-'08
How To Clear Code? P0420?
Ok Took My Car in For The Rearend additive..And Got The Car BAck with a CHECK ENGINE LIGHT..Never HAd this problem before..I Scanned it with my Predator and P0420 Catalystic System Efficience Below Threshold Bank 1 Came Up?? How do i get rid of this? Can someone Help me please..
Drifting
Joined: Jul 2003
Posts: 1,796
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From: Annandale VA
On a C5 you can reset it from the DIC. On a C6, you have to have it reset by a tuner or the dealer. I suspect you also be able to reset it by disconnecting the battery, but I really don't know for sure.
Make sure your real O2 sensor wasn't disconnected when you had the car serviced. If so, make them reset the code.
Make sure your real O2 sensor wasn't disconnected when you had the car serviced. If so, make them reset the code.
Thread Starter
Melting Slicks
Joined: Mar 2005
Posts: 2,517
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From: Palm beach Florida
St. Jude Donor '05-'06-'07-'08
well they said they tighten up my exhuast i had a few loose bolts on headers...and they told me they couldnt get the code out..so? can i do it with the predator? after i read the code. I tried to clear it and it didnt do it..So anyone else have an idea?
Safety Car
Joined: Dec 2004
Posts: 4,477
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From: Boca Raton, FL
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14
Erick
I have the Innova 3030 that I got at Wal-Mart. It cleared my P0449 code that was causing the CEL to stay on. The 3030 cost $69.
Jeff
I have the Innova 3030 that I got at Wal-Mart. It cleared my P0449 code that was causing the CEL to stay on. The 3030 cost $69.
Jeff
Race Director
Joined: Jan 2005
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From: Daytona Beach FL
Originally Posted by YellowVette22
Ok Took My Car in For The Rearend additive..And Got The Car BAck with a CHECK ENGINE LIGHT..Never HAd this problem before..I Scanned it with my Predator and P0420 Catalystic System Efficience Below Threshold Bank 1 Came Up?? How do i get rid of this? Can someone Help me please..
But, my Predator manual says 0420 is a COT enable temp code. When the Cats heat up too much, fuel will be added to cool the exhaust gas stream down.
You can adjust your COT enable temp with your Predator. The manual says only disable this if you don't have Cats. If you want to disable the code from setting, the manual says set your COT enable temp to a high 1200 degrees.
Bob
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Safety Car
Joined: Dec 2004
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From: Boca Raton, FL
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14
Originally Posted by YellowVette22
thanks jeff..hows the supercharger?
Burning Brakes
Joined: Jul 2006
Posts: 849
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From: Southern Florida
Originally Posted by YellowVette22
Ok Took My Car in For The Rearend additive..And Got The Car BAck with a CHECK ENGINE LIGHT..Never HAd this problem before..I Scanned it with my Predator and P0420 Catalystic System Efficience Below Threshold Bank 1 Came Up?? How do i get rid of this? Can someone Help me please..
Originally Posted by beezeye
But, my Predator manual says 0420 is a COT enable temp code. When the Cats heat up too much, fuel will be added to cool the exhaust gas stream down.
P0420 Catalyst System Low Efficiency Bank 1
P0430 Catalyst System Low Efficiency Bank 2
This is right from GM's service info.
Team Owner
Joined: Sep 2005
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From: Big Bend Country, TX
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15- '16-'17-‘18-‘19-'20-'21
NCM Lifetime Member
Originally Posted by wratran
i have the same code on my dynatech headers. One time is just disappear for awhile..but then it came back. I can clear it with code scanner...but then it would reappear.
Team Owner
Joined: Sep 2005
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From: Big Bend Country, TX
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15- '16-'17-‘18-‘19-'20-'21
NCM Lifetime Member
Originally Posted by Z06 Steve
this is a common problem code for LT headers the rear 02's dont reach the proper temp. easy fix just have your tuner shut off the code 
Le Mans Master
Joined: Feb 2006
Posts: 5,762
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From: Chandler Arizona
Originally Posted by 4 MY EGO
Sure, shut off the CEL. Then what happens if there is a major engine malfunction ?
I had the codes turned off and never had an issue. You really only have a few choices. 1) Turn off the codes, 2) Jet Hot the headers and hope they hold the heat in better, 3) Live with the codes
Team Owner
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From: Big Bend Country, TX
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15- '16-'17-‘18-‘19-'20-'21
NCM Lifetime Member
I have a better way to handle this. Remove the headers, the highflow intake and, the aftermarket catback. The car ran just fine when I took delivery. I truly wish I'd left it alone.
Race Director
Joined: Jan 2005
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From: Daytona Beach FL
Originally Posted by 4 MY EGO
I have a better way to handle this. Remove the headers, the highflow intake and, the aftermarket catback. The car ran just fine when I took delivery. I truly wish I'd left it alone.
I've got a Honker, Kooks, hiflow cats, and a Predator tune - which is probably the minimalist way to go. I love the car with my mods, and I've had no problems with that setup. A real dyno tune by a good tuner using HP Tuners or LS2 Edit tuning software would be better.
Most of the custom tunes will disable the COT input so your Cats don't throw that 0420 code. You can do it with a Predator by setting the COT enable to a high 1200 degrees so it just isn't a factor.
I think that's the problem YellowVette22 had that prompted his initial post. He had a custom tune, but put the factory tune back in with his Predator before a visit to the dealer. As soon as he reinstalls his custom tune that disables the COT parameter, I'm sure he won't have any problems.
Bob
Drifting
Joined: Jul 2005
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From: az
Originally Posted by GMautotech
YellowVette22 was right, 420 is an efficiency code.
P0420 Catalyst System Low Efficiency Bank 1
P0430 Catalyst System Low Efficiency Bank 2
This is right from GM's service info.
P0420 Catalyst System Low Efficiency Bank 1
P0430 Catalyst System Low Efficiency Bank 2
This is right from GM's service info.
this is on page 6-9094 my ego, this has nothing to do with COT, so jet hotting your header will not help you with these two code. basicly what is happening is your post cat o2 is just as active as the precat o2. your ecm is thinking the cats are old and not able to convert HC, CO & NOx into something that is environment friendly. if you were running no cat but left the post o2 sensors in there, you would get the same code plus some more codes.
Le Mans Master
Joined: Feb 2006
Posts: 5,762
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From: Chandler Arizona
Originally Posted by 4 MY EGO
I have a better way to handle this. Remove the headers, the highflow intake and, the aftermarket catback. The car ran just fine when I took delivery. I truly wish I'd left it alone.
Burning Brakes
Joined: Jul 2006
Posts: 849
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From: Southern Florida
Originally Posted by 4 MY EGO
Sure, shut off the CEL. Then what happens if there is a major engine malfunction ?