06 5.7 hemi check engine no code

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ntuttle

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Sep 28, 2013
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Ram Year
2006
Engine
5.7 Hemi
I have a 2006 2500 with a 5.7 Hemi, check engine light came on, when I did the key trick it didnt give me a code. The check engine light just flashes. Prior to today, I got a code that read P0420. I replaced all four O2 sensors. Can anyone tell me what issue could be now or why it isnt giving me a code and the check engine light is just flashing?
 
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ntuttle

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2006
Engine
5.7 Hemi
I replaced them with Bosch brand from autozone.
 
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ntuttle

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I would if I could! I am currently in South Korea!
 

hemihustlin

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5.7 HEMI
First thing you are going to hear is hemis hate bosch. Ntk all the way.
Secondly, speaking from experience, if you have a stock truck ( no exhaust mods) everytime ive seen a p0420 it is because the cats are finished.
Now, before replacing the cats you must find the underlying cause or thier failure. 99% of the time there is a reason not just oh its an old truck
 

03MopaRamman

RAM SPORT / 18 SRT
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2019 (2003 Forgottens SOLD and 2014 SOLD)
Engine
Hemi 5.7 (392 Hemi) 86 Ford .308 HO Roller
Did you reset the PCM. I get the Odd 420 but its not a worry for me but never a flashing Cel. Now i only have one Cat and when I pulled it at 160 k miles for a HF Magnaflow from Moes the OEM one was just fine, so thats not to say the cats are not bad like hustlin says as thats possible (hows the fuel in Korea?) Check for any small exhaust leaks upstream which that IMO could cause a cell and after reading this post reminds me to check tighten my 3 collector bolts at headers to mid pipe. The OEM exhaust gaskets are new with 6.1 threadlocked bolts so no need to check that but in your case also wouldn't hurt to look for any black streaks on the heads lower side of your manifolds as you cannot always hear it if you can feel a pin leak with your hand.
 
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Redtruck-VA

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2003 & 1989 D250 RWD
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Hemi-5.7, 5.9 12v & 24v diesel
I have been fortunate with not having exhaust codes even with changing the exhaust configuration several times. But I did notice that the front O2s is different from my rear one, but have not heard where folk have mentioned it in the threads. So it brings up the question, did the correct O2s get put in it's proper location?
 
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