OBD II Code 0420
OBD II Code 0420
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From: kansas
OBD II Code 0420
Late model cats are supposed to absorb any unused Oxygen to be used at any time when O2 content is low. Cats (catalytic converters} combine oxygen and carbon monoxide to form carbon dioxide. There should,nt be a lot of O2 content leaving the cat. There is an oxygen sensor behind the cat. It,s either defective or your cat is. Clear the code and see if the problem re-occurs. If it does , replacing the o2 sensor first is the cheaper of the two. Or you can buy a device that lies to the ECM.
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OBD II Code 0420
ok sounds good i wasnt shure if it was the one after or the one before or just the catalytic converter but i'll look into replacing the one after it and if that dosent work then the CC will have to be replaced
will this hurt anythingif its the o2 sensor or the catalytic converter and i dont fix it right away ?
thanks for your help
will this hurt anythingif its the o2 sensor or the catalytic converter and i dont fix it right away ?
thanks for your help
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From: Still under the hood in O
OBD II Code 0420
Generally no.
But if the cat is severely plugged, all kinds of bad can happen.
I found out the hard way....still working on it.
But you'll have warnings such as blowing gaskets.
But if the cat is severely plugged, all kinds of bad can happen.
I found out the hard way....still working on it.
But you'll have warnings such as blowing gaskets.
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OBD II Code 0420
Recently It has seemed that there is a "leaky" or blown gasket in the exhaustmanifold or something the engine sounds louder at high acceleration but not that much louder (not like a blown muffler) but dose sound like there is a leak someplace dose that sound familiar at all?
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From: Still under the hood in O
OBD II Code 0420
Well in my case I had the water pump gasket go first, it may have just be the weakest. But then eventually all the gaskets, valve cover/intake/front seal/one exhaust, just about all except the pan gasket.
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OBD II Code 0420
When i start it up in the morning there is some white smoke but when it warmes up it goes away, sounds to me maytbe the water pump gaskit might be going out? all signs point to the Cat so far so i'll look into that, but i will also check out the o2 sensor
Thanks alot for your help!
Thanks alot for your help!
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From: kansas
OBD II Code 0420
The ecm doesnt use the rear o2 sensor to adjust fuel /air mixture.The rear o2,s only purpose is to let owner know if cat is failing.EPA emission stuff. I,ve heard of a device that lies to the ecm so it wont turn the lite on(check engine). It works because Ive seen it on a 98 blown DOHC 4.6 cobra mustang with the cats removed. But if you have an exhaust leak anywhere near any o2s fix that first.
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My 96 has the same problem, took to the dealer 
and for $100 they told me I needed a new cat assy, as well as all 3 O2 sensors, and that the O2 sensor between the cat's was the wrong part # so I decided to start there with the correct part, then ran it to SMOG, and it passed. 2 days after that the CIL was back on and I have been ignoring it, that damn P O420 code really sucks and my dealer just told me to replace every component that it could have been to fix the problem, and that was like $4000 or so...Needless to say havnt done it yet, and no smog for 2 more years 
and for $100 they told me I needed a new cat assy, as well as all 3 O2 sensors, and that the O2 sensor between the cat's was the wrong part # so I decided to start there with the correct part, then ran it to SMOG, and it passed. 2 days after that the CIL was back on and I have been ignoring it, that damn P O420 code really sucks and my dealer just told me to replace every component that it could have been to fix the problem, and that was like $4000 or so...Needless to say havnt done it yet, and no smog for 2 more years
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The DEQ testing here in the Portland Oregon Metro area simply connects to your ODB-II connector (if so equipped) - they don't even put a 'sniffer' in your tailpipe. I imagine if they detect any code at all you fail.
I have a 96 Bronco with a 5.0 that has 3 O2 sensors - 1 in each exhaust manifold and another between the 2 cats after the exhaust has merged into one pipe.
I wonder if us truck guys could make a true dual header exhaust with dual primary and secondary cats like the Mustangs have - and get it to pass DEQ ?
Later,
Rusty
I have a 96 Bronco with a 5.0 that has 3 O2 sensors - 1 in each exhaust manifold and another between the 2 cats after the exhaust has merged into one pipe.
I wonder if us truck guys could make a true dual header exhaust with dual primary and secondary cats like the Mustangs have - and get it to pass DEQ ?
Later,
Rusty
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From: TITUSVILLE
you can check for a clogged exhaust system/cat with a vaccum gauge
Hook it up to manifold vaccum warm the engine raise the RPMs to 2500 - if the vaccum goes down - then recovers and then slowly looses vaccum - exhaust is clogged
Hook it up to manifold vaccum warm the engine raise the RPMs to 2500 - if the vaccum goes down - then recovers and then slowly looses vaccum - exhaust is clogged
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