P0420 maybe o2 sensor?
P0420 maybe o2 sensor?
So i replaced my rear o2 sensor a while back and ever since then i had a p0420 code but the thing is i think i put a front o2 on the rear (it has a really long wire) i ordered it on rock auto some generic one there wasnt even one in the car before and all i got was a low voltage for rear 02 cel which is understandable so i dont know if its because the cats bad the rear o2 is potentially a front one (if even possible) its because its generic or my cats bad (unknown aftermarket cat) anyone have any ideas?
P0420 is Catalytic Converter Below Efficiency Threshhold. I haven't seen a single case where it wasn't a blown out or gutted cat. The fact that there was no rear O2 also highly suggests that the cat is gutted.
The rear O2 can be a cheap generic O2 without any problem (it can also be missing without a problem other than a CEL), it's the front O2 that is much more expensive (~$250) and not something you can go generic on at all.
Pull the cat and look inside the front. I bet it's gutted:
The rear O2 can be a cheap generic O2 without any problem (it can also be missing without a problem other than a CEL), it's the front O2 that is much more expensive (~$250) and not something you can go generic on at all.
Pull the cat and look inside the front. I bet it's gutted:
P0420 is Catalytic Converter Below Efficiency Threshhold. I haven't seen a single case where it wasn't a blown out or gutted cat. The fact that there was no rear O2 also highly suggests that the cat is gutted.
The rear O2 can be a cheap generic O2 without any problem (it can also be missing without a problem other than a CEL), it's the front O2 that is much more expensive (~$250) and not something you can go generic on at all.
Pull the cat and look inside the front. I bet it's gutted:

The rear O2 can be a cheap generic O2 without any problem (it can also be missing without a problem other than a CEL), it's the front O2 that is much more expensive (~$250) and not something you can go generic on at all.
Pull the cat and look inside the front. I bet it's gutted:

You are dealing with the splines. This is what the front cat bolts look like:

No amount of torque will get them to rotate, the splines are locking it's position. Once you have the nuts off the back, hammer them out with a hand-sledge. Replace them with M10 exhaust bolts and nuts from your local auto parts store.

No amount of torque will get them to rotate, the splines are locking it's position. Once you have the nuts off the back, hammer them out with a hand-sledge. Replace them with M10 exhaust bolts and nuts from your local auto parts store.
Hey guys,
So I just popped the p0420 after about 500 mIles with the bhr midpipe. I was under the impression that the midpipe was made in a way that it wouldn't pop CAT lights. Is it possible that my o2 sensor is fouled, or is it just a midpipe thing? Thanks, sorry if this is something that has been killed a dozen times. I just speny a half hour in search and nothing turned up that was specific to my problem.
So I just popped the p0420 after about 500 mIles with the bhr midpipe. I was under the impression that the midpipe was made in a way that it wouldn't pop CAT lights. Is it possible that my o2 sensor is fouled, or is it just a midpipe thing? Thanks, sorry if this is something that has been killed a dozen times. I just speny a half hour in search and nothing turned up that was specific to my problem.
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MarkX
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Jul 31, 2015 07:50 AM



