CEL on, code is P0420

bryguycbr · 10-02-2016, 01:47 PM

CEL on, I have a Bosch OBD II reader, plugged it in and it shows P0420 - "Catalyst System Efficiency Below Threshold Bank 1".
Does anyone know what this would be causing/failing. Car drives OK, power seems to be OK, I had a new Stainless Works catback exhaust installed about 150 miles ago.
Still taking in for dealership to investigate CEL, but wanted a heads up on what you guys think it might be. I don't think my dealer will give me any grief on the exhaust.
Any thoughts.......Thanks

Glen e · 10-02-2016, 01:51 PM

Your exhaust screwed with the catalytic converter in someway. Prepare for this to be a customer pay issue, not warranty

bryguycbr · 10-02-2016, 02:15 PM

Quote:

Originally Posted by Glen e

Your exhaust screwed with the catalytic converter in someway. Prepare for this to be a customer pay issue, not warranty

I might take it to the guys that installed my exhaust and see what they think.
Thanks for reply.

somewhatdamaged · 10-02-2016, 02:21 PM

Sure seems like there's a lot of folks throwing codes with that catback for whatever reason, seems odd that it would happen when it doesn't touch the primary cats.

bryguycbr · 10-02-2016, 02:33 PM

Quote:

Originally Posted by somewhatdamaged

Sure seems like there's a lot of folks throwing codes with that catback for whatever reason, seems odd that it would happen when it doesn't touch the primary cats.

The guys that installed the exhaust are big time motor heads, they might learn something more about the 2016 Camaro. They tried talking me into very extensive motor upgrades.......and I told them hold up on this, let me drive the car a bit before you start tinkering with increasing the HP, they want to do all kinds of sh**t to this car.
Update: I added a Vitesse Throttle Controller last week, I removed it today, and will clear the CEL code from the car using the Bosch OBD II scanner. I'm thinking maybe the Throttle Controller has something to do with this problem, I'll update this post to give details of results.

bryguycbr · 10-03-2016, 04:06 PM

Cleared Check Engine Light using Bosch OBD II scanner, drove car for about 50 miles, all is good. Talked with exhaust installer (Twenty First Century Muscle Cars), he said sometimes cat will fail when new and it may only act up when starting cold engine, if CEL comes on and is same code (P0420) I'll take to GM dealer for repair, if GM does not want to repair, exhaust installer will replace cat, he has a lot of spares and will fix issue for free. I told 21st CMC I had a throttle controller installed, but he didn't think that should cause a CEL or cat to fail. So, I'll keep the throttle controller removed and try to put some miles on the car and update later.

bryguycbr · 10-05-2016, 10:04 PM

Drove car, now have 6712 miles, check engine light still off, Vitesse Throttle Controller originally caused P0420 - "Catalyst System Efficiency Below Threshold Bank 1".
I will not use that again, I'm going to talk with them and see what they have to say about their item causing CEL to appear.

Richard0nee · 10-05-2016, 10:53 PM

Vitesse throttle controllers have been known to throw codes which is why I stay away from them. I know there are members that have used them with no problems so good for them.

Then again, I have no delays or sluggish throttle so I don't really need it anyways.

1LE801 · 10-06-2016, 12:35 AM

That throttle controller is JUNK!

bryguycbr · 10-06-2016, 10:13 AM

Quote:

Originally Posted by Richard0nee

Vitesse throttle controllers have been known to throw codes which is why I stay away from them. I know there are members that have used them with no problems so good for them.

Then again, I have no delays or sluggish throttle so I don't really need it anyways.

I sent an E-mail to Vitesse explaining what happened, will be interesting what their reply is.
The few miles I had it installed, it worked OK, but in time rear tires will be worn out from excessive acceleration. The SS doesn't need any help with throttle.

bryguycbr · 10-07-2016, 05:26 PM

I now have 6780 miles, no CEL, my best guess is Vitesse Throttle Controller caused CEL with code P0420.

bryguycbr · 10-10-2016, 10:11 PM

CEL back on P0420, New Stainless Works Catback exhaust causing CEL, having it looked at this Thursday, this 2016 SS is very sensitive to any changes.

Richard0nee · 10-11-2016, 12:07 AM

Damn that's some shit. Have them recheck all the weld points.

Keep us updated

V8Addict · 10-11-2016, 04:22 PM

guess you jumped the gun when you blamed the throttle controller.

10-02-2016, 01:47 PM	#1
bryguycbr Drives: 2016 2SS Nightfall Gray Join Date: Apr 2016 Location: North Texas Posts: 131	CEL on, code is P0420 CEL on, I have a Bosch OBD II reader, plugged it in and it shows P0420 - "Catalyst System Efficiency Below Threshold Bank 1". Does anyone know what this would be causing/failing. Car drives OK, power seems to be OK, I had a new Stainless Works catback exhaust installed about 150 miles ago. Still taking in for dealership to investigate CEL, but wanted a heads up on what you guys think it might be. I don't think my dealer will give me any grief on the exhaust. Any thoughts.......Thanks __________________ 2016 2SS, Nightfall Gray Metallic, Jet Black Leather, A8, MRC, Clear-Bra, ROTO-FAB CAI sound tube removed, Stainless Works Catback with AFM valves, ORACLE ghosted sidemarker set

10-02-2016, 01:51 PM	#2
Glen e Retired from Car mfrs.... Drives: 2LT RS/HR-V Join Date: May 2013 Location: /Fort Lauderdale Posts: 10,044	Your exhaust screwed with the catalytic converter in someway. Prepare for this to be a customer pay issue, not warranty __________________ Glen CLICK HERE for detailing a new car: detailing for non detailers CLICK HERE for how to rinseless CLICK HERE for EASY wheel sealant

10-03-2016, 04:06 PM	#6
bryguycbr Drives: 2016 2SS Nightfall Gray Join Date: Apr 2016 Location: North Texas Posts: 131	Cleared Check Engine Light using Bosch OBD II scanner, drove car for about 50 miles, all is good. Talked with exhaust installer (Twenty First Century Muscle Cars), he said sometimes cat will fail when new and it may only act up when starting cold engine, if CEL comes on and is same code (P0420) I'll take to GM dealer for repair, if GM does not want to repair, exhaust installer will replace cat, he has a lot of spares and will fix issue for free. I told 21st CMC I had a throttle controller installed, but he didn't think that should cause a CEL or cat to fail. So, I'll keep the throttle controller removed and try to put some miles on the car and update later. __________________ 2016 2SS, Nightfall Gray Metallic, Jet Black Leather, A8, MRC, Clear-Bra, ROTO-FAB CAI sound tube removed, Stainless Works Catback with AFM valves, ORACLE ghosted sidemarker set

10-05-2016, 10:04 PM	#7
bryguycbr Drives: 2016 2SS Nightfall Gray Join Date: Apr 2016 Location: North Texas Posts: 131	Drove car, now have 6712 miles, check engine light still off, Vitesse Throttle Controller originally caused P0420 - "Catalyst System Efficiency Below Threshold Bank 1". I will not use that again, I'm going to talk with them and see what they have to say about their item causing CEL to appear. __________________ 2016 2SS, Nightfall Gray Metallic, Jet Black Leather, A8, MRC, Clear-Bra, ROTO-FAB CAI sound tube removed, Stainless Works Catback with AFM valves, ORACLE ghosted sidemarker set

10-06-2016, 12:35 AM	#9
1LE801 "Lohla" Drives: 2016 1SS A8 :"Lohla" Join Date: Dec 2013 Location: Utah Posts: 711 View My Garage	That throttle controller is JUNK! __________________ OG Trans and Diff but all else is upgraded. Twins bring wins ;-)

10-02-2016, 02:21 PM	#4
somewhatdamaged Drives: 16' 2SS M6 Join Date: Feb 2010 Location: Earth Posts: 573	Sure seems like there's a lot of folks throwing codes with that catback for whatever reason, seems odd that it would happen when it doesn't touch the primary cats.

10-05-2016, 10:53 PM	#8
Richard0nee Drives: 2016 SS M6, NPP Join Date: Apr 2016 Location: Hawthorne, CA Posts: 1,957	Vitesse throttle controllers have been known to throw codes which is why I stay away from them. I know there are members that have used them with no problems so good for them. Then again, I have no delays or sluggish throttle so I don't really need it anyways.

10-07-2016, 05:26 PM	#11
bryguycbr Drives: 2016 2SS Nightfall Gray Join Date: Apr 2016 Location: North Texas Posts: 131	I now have 6780 miles, no CEL, my best guess is Vitesse Throttle Controller caused CEL with code P0420. __________________ 2016 2SS, Nightfall Gray Metallic, Jet Black Leather, A8, MRC, Clear-Bra, ROTO-FAB CAI sound tube removed, Stainless Works Catback with AFM valves, ORACLE ghosted sidemarker set

10-10-2016, 10:11 PM	#12
bryguycbr Drives: 2016 2SS Nightfall Gray Join Date: Apr 2016 Location: North Texas Posts: 131	CEL back on P0420, New Stainless Works Catback exhaust causing CEL, having it looked at this Thursday, this 2016 SS is very sensitive to any changes. __________________ 2016 2SS, Nightfall Gray Metallic, Jet Black Leather, A8, MRC, Clear-Bra, ROTO-FAB CAI sound tube removed, Stainless Works Catback with AFM valves, ORACLE ghosted sidemarker set

10-11-2016, 12:07 AM	#13
Richard0nee Drives: 2016 SS M6, NPP Join Date: Apr 2016 Location: Hawthorne, CA Posts: 1,957	Damn that's some shit. Have them recheck all the weld points. Keep us updated

10-11-2016, 04:22 PM	#14
V8Addict Drives: 2016 2SS Join Date: Feb 2010 Location: So Calif Posts: 324	guess you jumped the gun when you blamed the throttle controller. __________________ 2016 Hyper Blue 2SS, A8, NPP, MRC

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