Headers and P0420
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From: SoCal
Headers and P0420
Since I got my Kooks/HF Cats/Xpipe I have got yellow engine light and code P0420 H C.
Has happened two times each time with about the same milage after one week of driving. Never had an engine light/ code before install.
Can anyone tell me about this?
Has happened two times each time with about the same milage after one week of driving. Never had an engine light/ code before install.
Can anyone tell me about this?
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Been there, done that. Similar code, the 0420 I believe is one side and the 0430 is the other. A fairly common code seen with long tube headers and high flow cats.
I threw the 0430 first, cleared it out, only to throw both the 0420 and the 0430 a few days later before having the rear O2s edited out.
http://forums.corvetteforum.com/showthread.php?t=894181
You'll have to have the rear O2 sensors edited out.
I threw the 0430 first, cleared it out, only to throw both the 0420 and the 0430 a few days later before having the rear O2s edited out.
http://forums.corvetteforum.com/showthread.php?t=894181
You'll have to have the rear O2 sensors edited out.
Last edited by '06 Quicksilver Z06; Sep 18, 2004 at 02:05 AM.
Thread Starter
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From: SoCal
Originally Posted by EB20003
Been there, done that. Similar code, the 0420 I believe is one side and the 0430 is the other. A fairly common code seen with long tube headers and high flow cats.
I threw the 0430 first, cleared it out, only to throw both the 0420 and the 0430 a few days later before having the rear O2s edited out.
http://forums.corvetteforum.com/showthread.php?t=894181
You'll have to have the rear O2 sensors edited out.
I threw the 0430 first, cleared it out, only to throw both the 0420 and the 0430 a few days later before having the rear O2s edited out.
http://forums.corvetteforum.com/showthread.php?t=894181
You'll have to have the rear O2 sensors edited out.
So does this mean that my sensors went bad from the install or were damaged or need to be cleaned or wires are fried?***I dought this is the case since I had A&A do the install and Andy does careful and quality work!!
Or is this just a nuisance problem??
Last edited by Macinamouth; Sep 18, 2004 at 02:32 AM.
Burning Brakes
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From: Bakersfield, Blown 402 Z06 Ca
Sorry to say but, don't edit you o2 sensors out because you will need them for your smog check. Replace the 02's and you will be fine. I put the Kook's on my 2000 C5 and the check engine lite would come on after about 5 miles of driving. The car had 50,000 miles on it and that's about all the 02's are good for. Replaced 02's and no more codes or check engine lite. 
Last edited by gairno; Sep 18, 2004 at 03:11 AM.
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Not doubting you, and just for my own information, but why does he need them for his smog check?
Also, it would seem that new 02 sensors are only going to "report" the same "problem". That his new catalytic converters are "inefficient" when in fact they are not.
Not being familiar with the CA smog testing procedures, please inform me. I thought it was a visual test and a sniffer test. If he passes the sniffer, how would they know if his 02 sensors are functional or not, as his car would not store nor report any emission codes were it checked for emissions codes.
He says his car is an '04 so its doubtful that he has 50k miles on it. Seems sort of odd to have to replace the 02 sensors on such a new car.
Also, it would seem that new 02 sensors are only going to "report" the same "problem". That his new catalytic converters are "inefficient" when in fact they are not.
Not being familiar with the CA smog testing procedures, please inform me. I thought it was a visual test and a sniffer test. If he passes the sniffer, how would they know if his 02 sensors are functional or not, as his car would not store nor report any emission codes were it checked for emissions codes.
He says his car is an '04 so its doubtful that he has 50k miles on it. Seems sort of odd to have to replace the 02 sensors on such a new car.
Last edited by '06 Quicksilver Z06; Sep 18, 2004 at 04:14 PM.
Melting Slicks
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From: California
Originally Posted by EB20003
Not doubting you, and just for my own information, but why does he need them for his smog check?
Also, it would seem that new 02 sensors are only going to "report" the same "problem". That his new catalytic converters are "inefficient" when in fact they are not.
Not being familiar with the CA smog testing procedures, please inform me. I thought it was a visual test and a sniffer test. If he passes the sniffer, how would they know if his 02 sensors or functional or not, as his car would not store nor report any emission codes were it checked for emissions codes.
He says his car is an '04 so its doubtful that he has 50k miles on it. Seems sort of odd to have to replace the 02 sensors on such a new car.
Also, it would seem that new 02 sensors are only going to "report" the same "problem". That his new catalytic converters are "inefficient" when in fact they are not.
Not being familiar with the CA smog testing procedures, please inform me. I thought it was a visual test and a sniffer test. If he passes the sniffer, how would they know if his 02 sensors or functional or not, as his car would not store nor report any emission codes were it checked for emissions codes.
He says his car is an '04 so its doubtful that he has 50k miles on it. Seems sort of odd to have to replace the 02 sensors on such a new car.
You (like Me), will need the rear o2's for smog. If you remove them with Tuning you will fail the OBD2 scan at the smog station.
That being said... I removed mine. We won't have to smog our cars until the 4th or 5th year we own them (can't remember if it's 4 years of no smog check, or 4 years until the first...). I am going to run my car with the LGs in it's state until I have to smog. If there are no "workarounds"
at that time I will then replace the stock exhaust, tuning and other mods that I would need to. I see this as an extra weekend in the garage before and after the smog check. Not alot to ask for 4 years of fun in between. Heck, when it's stock again I may find it's time for a new C6-Z06. That's what I did on my previous Camaros, returned to stock, then sold the parts and the cars, then upgraded. Who knows....
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St. Jude Donor '06-'07
in Texas the OBD2 smog test system looks for fault codes and system readiness . The test system checks that no codes have been thrown by the computer .If you have no code than no fault .I have no cats and my car tests out fine with the trouble code 0420 and 0430 deleted .It shows no faults and system shows ready which is required to pass smog . Our emissions testing is closest to testing in california as far as i know .
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Melting Slicks
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From: California
Originally Posted by NOT-MEE
in Texas the OBD2 smog test system looks for fault codes and system readiness . The test system checks that no codes have been thrown by the computer .If you have no code than no fault .I have no cats and my car tests out fine with the trouble code 0420 and 0430 deleted .It shows no faults and system shows ready which is required to pass smog . Our emissions testing is closest to testing in california as far as i know .
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From: SoCal
Originally Posted by Tony_C5_04
Over the summer my friend's car failed the OBD portion of the California emmissions test because he had codes removed. This test looks to see that the codes are in fact being monitored by the PCM, so if they probe it and the PCM responds as not knowing that code, you fail. He passed the sniffer test with long tubes and cats with a 224 cam. He removed the rear O2 codes because they were setting codes, and the P0300 misfire code due to the cam idle.
I agree that if I can't find a smog facility that will over look the visual inspection that I will have to pay for the dinstall and reinstall of the Kooks and love them until that time. Who knows...I could be dead by then.
This OBD stuff confuses me. Should you actually let the codes remain in history and not clear them before the actual testing. I am hopeful that since this is computer technology that there is always a way to crack/hack!!! Maybe swapping a "clean/virgin" PCM just before the test.
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A way around that could be to edit the rear O2 sensors out to prevent the check engine light from coming on.
Then on the day of the inspection re activate them. Since it takes several miles for the code to set, ( it actually took me 144 miles to set it, the first time and 143 miles to set it the second time) a car might pass the test and throw the code on the way back home, or as far off as a couple days later.
Of course the code could not set before the test was over, for if it did, I am sure that would result in failure. However if it did, the owner would be no worse off.
As I recall, it also goes by the number of engine starts, and this plays a role in setting the code.
My last Predator tune has my rear 02s edited out to keep from setting the code. But the one before that still has them in. They are both in my computer and either can be downloaded into my car's PCM. I'd be inclined to try that approach or something similar before I would hurry to uninstall my headers. But I am not in California.
Take the above advice at your own risk and be aware of any laws which may apply should you try this.
Then on the day of the inspection re activate them. Since it takes several miles for the code to set, ( it actually took me 144 miles to set it, the first time and 143 miles to set it the second time) a car might pass the test and throw the code on the way back home, or as far off as a couple days later.
Of course the code could not set before the test was over, for if it did, I am sure that would result in failure. However if it did, the owner would be no worse off.
As I recall, it also goes by the number of engine starts, and this plays a role in setting the code.
My last Predator tune has my rear 02s edited out to keep from setting the code. But the one before that still has them in. They are both in my computer and either can be downloaded into my car's PCM. I'd be inclined to try that approach or something similar before I would hurry to uninstall my headers. But I am not in California.
Take the above advice at your own risk and be aware of any laws which may apply should you try this.
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St. Jude Donor '06-'07
if you clear the code right before less than 50 miles you computer will read not ready and it will fail emissions.You could try o2 simulators but some people have had issues with them.As for the headers hopefully no look no tell approach will work.
4th Gear
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hey
im a noobie here. but if u didnt edit the rear o2 sensors or clear the code the light would stay on i have gathered. Now my question is, besides being irritating to look at everytime you drive the car, is there anything wrong with just ignoring it? does it affect the way the car runs?
Thanks
Rick
Thanks
Rick
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From: Vette-hid.com Lost in DFW texas
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St. Jude Donor '06-'07
Originally Posted by stealthc5
is there anything wrong with just ignoring it? does it affect the way the car runs?
Thanks
Rick
Thanks
Rick
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The two codes(0420 0430) are eliminated(deleted) by Ls1 edit now no issues at all. Andy at 21st century musclecars did the magic not me.I have been treated great over their and they were more than willing to help cure the issues i had. They did the tune and fixed it all.
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St. Jude Donor '06-'07
here is a site for info on the obd2 test in texas. All the test really looks for is system readiness without codes system shows ready.
http://www.txdps.state.tx.us/vi/Misc..._faq.htm#where
http://www.txdps.state.tx.us/vi/Misc..._faq.htm#where
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From: SoCal
Not-Me: Good info. Sounds like clear PCM, run 50 miles go do Smog Test.
EB20003: Mine has gone of the last two friday mornings on the way to work. I put on pretty much equal miles on my car each week...approximatly 550 miles. I'll bet I see it again this friday.
EB20003: Mine has gone of the last two friday mornings on the way to work. I put on pretty much equal miles on my car each week...approximatly 550 miles. I'll bet I see it again this friday.
Race Director
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mac: i think that is the code for "please give me an a&a blower kit under the hood asap."
don't deny that which your car needs.
don't deny that which your car needs.
Originally Posted by Macinamouth
Since I got my Kooks/HF Cats/Xpipe I have got yellow engine light and code P0420 H C.
Has happened two times each time with about the same milage after one week of driving. Never had an engine light/ code before install.
Can anyone tell me about this?
Has happened two times each time with about the same milage after one week of driving. Never had an engine light/ code before install.
Can anyone tell me about this?
Thread Starter
Team Owner
Joined: May 2004
Posts: 26,345
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From: SoCal
Originally Posted by SLO VETTE
mac: i think that is the code for "please give me an a&a blower kit under the hood asap."
don't deny that which your car needs.
don't deny that which your car needs.
Andy already told me what I need....H/C
But the blower I won't be usin will fit in that new ride you have
