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P0420 w/ High Flow Cats

Bowlerguy92

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#1
Hi guys,

I've seen P0420 a couple of times now on my less than stock hellcat. I have catted high flows as part of the build and hadn't had an issue with CEL's at all until about 6 weeks ago when I had the car inspected and passed successfully. Emissions is part of our state inspection here in NH so I know at that time everything was functioning properly or it would have failed. Driving back home from the shop was the first time I had seen the code pop up. I had thousands of miles prior to that on this setup without issue. I got home, cleared it and it didn't come back on for weeks until this past Friday on the way home from the track.

Fairly hot day out and quite a few passes so I'm sure the cats got really really toasty but otherwise, nothing out of the ordinary aside from me having swapped to my race gas tune the day before. The code came back after I had left the track for the day and was cruising home.

Do I just clear it again? The car put down a 9.8x pass at the strip and is otherwise running phenomenally. Is there a precedent for high flows setting this code off? Is this something Jon can tune out by increasing a threshold if that's the case?
 


vortecd

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#2
Should have them shut off in the tune and have another tune for your emission testing
 


OP
Bowlerguy92

Bowlerguy92

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Thread Starter #3
Alright, I'll have Jon shut them off at least in the race gas tune so I don't get that anymore. Will delete the code for now.
 


jonx96

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#4
Should have them shut off in the tune and have another tune for your emission testing
He has emission testing. Hi flow cats will still throw a code sometimes. You are actually supposed to have green gates to pass emissions.
 


OP
Bowlerguy92

Bowlerguy92

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NH
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2022 Hellcat Charger Redeye Widebody
Thread Starter #5
He has emission testing. Hi flow cats will still throw a code sometimes. You are actually supposed to have green gates to pass emissions.
Ya, the car passed fine on my 93 tune. Just have seen the P0420 pop up a couple of times now recently and didn't know if it was something to be concerned about or just ignore. Sounds like just ignore.
 




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