Please help before I go insane

[NCRaineman]

If you've been living with it for three years obviously you aren't in an emissions state, otherwise you wouldn't pass inspection with the emissions code in the computer. Not that I'd suggest it, but you could just remove the cats, tune out the downstream O2 sensors and be done with the whole mess.

 

[turkeybird56]

just on an odd ball chance that the o2 sensors are correct for each position, OfCourse there are 4 but two have different part numbers and make sure they are in the position they are intended for , mixing them up will send the wrong infor to the ecm and could cause the engine light on , and relate to this problem

YUP, 4 sensors. 2 for up stream/2 for downstream. Wouldn't be the 1st time someone put them in reverse order, just a saying, something to check. BUT as far as OEM: on these finicky things, ONLY OEM sensors, nothing else. IMHO.

 

[karkrafter]

I can't speak to your exact issue but in dealing with the dreaded 420 code in the past I have found a couple things...some vehicles are super fussy as to what brand o2 sensor you use. Sometimes you just HAVE to use oem...secondly, cleaning the cat has never worked for me. Might shut the light off long enough to get smogged but that was about it. As for the cats you used, IF your vehicle is a California emissions vehicle and you used a federal emissions cat...light is gonna come on, period. You can try to move the rear o2 and hide it a bit. This might work, or it might now. A good computer guy should be able to read the sensor with a scan tool and tell you what the issue is.

 

[weldguy]

We're the O2 sensors MoPar or aftermarket? Years ago I learned to use only OEM.

 

[Tominator223]

I had similar issue with my 04.5.7. The new cats I got were to small . (Short). Aftermarket cats will work fine. The man I got my cat’s from said there is no high flow cat’s because they all have the same substrate . But if their too small you’ll have issues. He was right as I now have over 150k on aftermarket cat’s. & no codes since replaced. If your o2’s were not moved they should be fine.

 

[Dusty]

We're the O2 sensors MoPar or aftermarket? Years ago I learned to use only OEM.

I've only known one vehicle where aftermarket O2 sensors worked without issue: a 2017 Tundra.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 10118 miles.

 

[pacofortacos]

This is guaranteed to get rid of the post cat code, I used it on a gutted cat without issue in an I/M testing state.

O2 Simulator Mini Cat Cel Fix stainless steel Rear O2 sensor simulator.

O2 Simulator Mini Cat Cel Fix, Big Daddies Garage Mini Catalytic Convertor Rear Oxygen Sensor Simulator is the best and easiestway to clear p0420 / p0430 codes for bad or missing catalytic converters. Just screw it the o2 simulator mini cat into the existing exhaust then srew in the oxygen...

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