Help PO420 and now PO430 CEL - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

AieaboyHI · 12-17-2019, 03:18 PM

Here’s the skinny, 2011 3.6, auto, 117k. Original owner. No mods, bone stock. Uses up 1 quart of oil every 5k. Every now and then the CEL comes on and I download the code as a 420 And/or 430 codes. I can go as long as 15,000 miles and the light won’t go on however, lately it’s been going off every 500-1k. I live in Commiefornia and have to pass smog every 2 years. lucky I went 500 miles after clearing the code and it passed smog. my question is, in my internet research there’s a good possibility of a defective 02 sensor. There’s a good possibility it’s also the catalytic converter’s. With that being said, the smog guy guaranteed that my catalytic converter’s are not going out with the mileage being 117 K. Of course he’s a smog tech and not a mechanic. Has anyone else had this issue? And what was the resolution? Thanks!

Greenhornet2 · 12-17-2019, 06:29 PM

Lol, you cannot guarantee your cats are not going out... that is a ridiculous statement. Typically a po420 or p0430 almost always is due to the cat. As it is deteriorating more the house comes up quicker. O2 sensors are pretty good at throwing codes if they have a slow response, voltage issue or heater fault. Given you've never gotten an o2 code it's most likely your cats

AieaboyHI · 12-18-2019, 09:25 AM

That’s what I was afraid of. I know failed O2 sensors will trigger their own code. The commiefornia compliant catalytic converter‘s are absolutely ridiculously priced.
Cataclean?

ForgotUsername · 12-18-2019, 09:36 AM

I have the same issue, 2010 3.6 automatic 136k, P0420 P0430
The problem has been intermittent since maybe 110k miles and it comes back up more frequently, at this point it's on almost immediately after I clear it. I haven't diagnosed the issue though.

AieaboyHI · 12-18-2019, 09:50 AM

Quote:

Originally Posted by ForgotUsername

I have the same issue, 2010 3.6 automatic 136k, P0420 P0430
The problem has been intermittent since maybe 110k miles and it comes back up more frequently, at this point it's on almost immediately after I clear it. I haven't diagnosed the issue though.

That’s what I’m afraid of. Right now I’m getting CEL free for about 250 miles to 2000. Just long enough to pass smog.

Greenhornet2 · 12-18-2019, 09:58 AM

Yea both of you guys have smoked cats I have a pair of OEM cats but they are for the SS

TommyTheCat · 12-18-2019, 10:14 AM

as a commiefornia smog tech myself i can guarantee you that the first smog tech was an idiot, you can definitely have a cat go bad at 115k miles and sooner.

The problem isn't that catalysts don't last as long as they used to, it's that they trigger the codes much sooner. As an exaggerated example... in 2000 a catalyst can be functioning at 50% and still pass the monitor, but in 2010 the monitor can fail just because the catalyst is only functioning at 80%.

now that being said, there is still a possibility you'll need O2 sensors, but it's much more likely for catalysts (basically filters) to be working less efficiently than both rear o2 sensors to fail at the same time. still possible, not likely. there are legal aftermarket catalysts for your car depending on your engine family number

12-17-2019, 03:18 PM	#1
AieaboyHI Drives: 2011 IBM 1LT RS Join Date: May 2011 Location: Sacramento Posts: 132	Help PO420 and now PO430 CEL Here’s the skinny, 2011 3.6, auto, 117k. Original owner. No mods, bone stock. Uses up 1 quart of oil every 5k. Every now and then the CEL comes on and I download the code as a 420 And/or 430 codes. I can go as long as 15,000 miles and the light won’t go on however, lately it’s been going off every 500-1k. I live in Commiefornia and have to pass smog every 2 years. lucky I went 500 miles after clearing the code and it passed smog. my question is, in my internet research there’s a good possibility of a defective 02 sensor. There’s a good possibility it’s also the catalytic converter’s. With that being said, the smog guy guaranteed that my catalytic converter’s are not going out with the mileage being 117 K. Of course he’s a smog tech and not a mechanic. Has anyone else had this issue? And what was the resolution? Thanks!

12-17-2019, 06:29 PM	#2
Greenhornet2 Drives: 2011 Camaro 2SS LS3 Whipple Join Date: May 2019 Location: Connecticut Posts: 1,925	Lol, you cannot guarantee your cats are not going out... that is a ridiculous statement. Typically a po420 or p0430 almost always is due to the cat. As it is deteriorating more the house comes up quicker. O2 sensors are pretty good at throwing codes if they have a slow response, voltage issue or heater fault. Given you've never gotten an o2 code it's most likely your cats __________________ Whipple 2.9 CAI ID1050x injectors ZL1 Pump JRE FPCM JMS Voltage booster JRE Rough Idle blower cam BTR .660 springs CHE trunnion kit 1 7/8 Speed Engineering Borla Atak JRE scoop 1.5" lowering springs BMR trailing arms and toe links Cradle inserts 704WHP 603WTQ 93 octane

12-18-2019, 09:58 AM	#6
Greenhornet2 Drives: 2011 Camaro 2SS LS3 Whipple Join Date: May 2019 Location: Connecticut Posts: 1,925	Yea both of you guys have smoked cats I have a pair of OEM cats but they are for the SS __________________ Whipple 2.9 CAI ID1050x injectors ZL1 Pump JRE FPCM JMS Voltage booster JRE Rough Idle blower cam BTR .660 springs CHE trunnion kit 1 7/8 Speed Engineering Borla Atak JRE scoop 1.5" lowering springs BMR trailing arms and toe links Cradle inserts 704WHP 603WTQ 93 octane

12-18-2019, 09:25 AM	#3
AieaboyHI Drives: 2011 IBM 1LT RS Join Date: May 2011 Location: Sacramento Posts: 132	That’s what I was afraid of. I know failed O2 sensors will trigger their own code. The commiefornia compliant catalytic converter‘s are absolutely ridiculously priced. Cataclean?

12-18-2019, 09:36 AM	#4
ForgotUsername Drives: 2010 Camaro RS LT2 Join Date: May 2018 Location: Detroit Posts: 17	I have the same issue, 2010 3.6 automatic 136k, P0420 P0430 The problem has been intermittent since maybe 110k miles and it comes back up more frequently, at this point it's on almost immediately after I clear it. I haven't diagnosed the issue though.

12-18-2019, 10:14 AM	#7
TommyTheCat SHKE BKE Drives: 2013 Camaro Join Date: May 2014 Location: SoCal Posts: 3,108	as a commiefornia smog tech myself i can guarantee you that the first smog tech was an idiot, you can definitely have a cat go bad at 115k miles and sooner. The problem isn't that catalysts don't last as long as they used to, it's that they trigger the codes much sooner. As an exaggerated example... in 2000 a catalyst can be functioning at 50% and still pass the monitor, but in 2010 the monitor can fail just because the catalyst is only functioning at 80%. now that being said, there is still a possibility you'll need O2 sensors, but it's much more likely for catalysts (basically filters) to be working less efficiently than both rear o2 sensors to fail at the same time. still possible, not likely. there are legal aftermarket catalysts for your car depending on your engine family number