all i need is a quick answer

[dumbkid]

hey guys, i have a quick question on a recent cel my engine threw. i know that p0420 is an o2 sensor, i just need to know which one. and if possible if there is a quick fix.

thnks

[s2keepup]

(im waiting for dave ~repiv~ to chime in) :hehe: he is our resident expert and is quick to help :thumbsup:

[darkside]

Catalyst system efficiency below threshold.

[dumbkid]

i know that, but i need to know what o2 sensor it is. thanks anyway for your help

[RatedR]

How many miles? Its a regular maintenance replacable item. If you haven't replaced them, it wouldnt be bad to replace both. I would suggest clearing the code first to see if it comes back. Then you know that it wasn't a fluke. Its quick and its free.

[pininfarina456]

Sounds like secondary, but I'm not sure.

[WestSideBilly]

P0420 means the O2 sensor after the catalytic converter is reading O2 levels similar to the primary O2 sensor. It does not automatically mean the secondary sensor has failed. There are several possibilities:

1) The primary has failed and is reading high.
2) The secondary has failed and is reading low. (most likely)
3) Both have failed.
4) Your catalytic converter is not working properly. (least likely)

There is no quick fix. You will need to determine if the cat is functioning and if not which of the O2 sensors has failed. This can be done fairly easily with a volt-ohm meter, but you need to get under the car and pull the plugs to get at the terminals.

[Domino]

Are you running an aftermarket exhaust?

[repiv]

Are you running an aftermarket exhaust?

Or you've put on a test pipe? That CEL code is pointing towards your catalytic converter, therefore, it's the one in the cat. The other one is in the header and is the primary O2 sensor.
Billy's got it covered.

[gomarlins3]

Way to go Billy!!

[rioyellows2k]

Catalytic converters are covered up to 80K under the Fed. Emissions requirements....

[repiv]

Catalytic converters are covered up to 80K under the Fed. Emissions requirements....

Unless he's done something to his .................... like having taken it off or drilling it full of holes or gutting it or used a lead additive in the fuel or drove over something and dented it. He hasn't indicated any details on this as yet.

[dumbkid]

sorry guys, i've away for a moment.

no after market parts, 90,400 miles on the bone stock engine. also, this cel comes on for a couple of days and go's off for a couple. performance is not affected at all that i've noticed. i'll reset the ecu, and see what happens, it also read that there is the same code pending.

it's really insane how many post's there are refering to this trouble spot, but none seemed to indicate what the problem was. i greatly appriciate all of your help. keep it coming!

[darkside]

sorry guys, i've away for a moment.

no after market parts, 90,400 miles on the bone stock engine. also, this cel comes on for a couple of days and go's off for a couple. performance is not affected at all that i've noticed. i'll reset the ecu, and see what happens, it also read that there is the same code pending.

it's really insane how many post's there are refering to this trouble spot, but none seemed to indicate what the problem was. i greatly appriciate all of your help. keep it coming!


The reason there is no "true" answer. You are dealing with something that has two parts that work together, when one is not working it will effect the other therefore throwing a code.
Bottom point its not an easy answer, you can always try and trick the sensor using spacers you seem you are looking for easy fix.

[repiv]

You could try to find someone who has discarded his cat for a t. pipe a long time ago and put it on your car to see if that's what wrong. Depending on the state of tune your engine has been in or the type of fuel that has been used, maybe the cat is just plain wearing out.

[dumbkid]

i want a test pipe, but from what i understand , and with the problems i had with my DA, the same code will be thrown. i've heard the spacers are also hit and miss. i'll be doing an oil change this week, so i'll check it out then. thanks for all of your help.

[repiv]

Sparkplug non-foulers should be used and are not just spacers. They move the end of the sensor further away from the stream of exhaust AND they also restrict the size of the passageway to the sensor tip. These non-foulers needed to be "doctored" up before use. It's only been hit and miss if the wrong set up has been used. For example, the original Berk test pipe came with a built in extension for the sensor. The biggest problem with this was that the extension was angled INTO the flow of the exhaust and there was NO restriction. It was a really silly design and sometimes it worked and sometimes it didn't. Simply moving the sensor away from the exhaust is not enough. It was only hit and miss for those who didn't understand the concept.

[s2k 4 me]

:above: I agree with Dave, I recently bought a Berk test pipe and after installing it got the CEL. I sold it and bought Berk's High Flow Cat and the CEL went away immediately.

And also I couldnt stand the "Sand storm" sound that the test pipe makes...drove me :willynilly:

[repiv]

:above: I agree with Dave, I recently bought a Berk test pipe and after installing it got the CEL. I sold it and bought Berk's High Flow Cat and the CEL went away immediately.

And also I couldnt stand the "Sand storm" sound that the test pipe makes...drove me :willynilly:

This may be a small thread jack, but perhaps that Berk HF cat is a good alternative for those who may have an old, dying cat. Isn't this a lot cheaper than the OEM cat?
I was getting clouds of black smoke with a t. pipe due to the extra exhaust of the supercharger at full boost. I had to get rid of the t. pipe for that reason. Do you notice any unusual smoking with the Berk cat at full throttle and high rpm?

[s2k 4 me]

This may be a small thread jack, but perhaps that Berk HF cat is a good alternative for those who may have an old, dying cat. Isn't this a lot cheaper than the OEM cat?
I was getting clouds of black smoke with a t. pipe due to the extra exhaust of the supercharger at full boost. I had to get rid of the t. pipe for that reason. Do you notice any unusual smoking with the Berk cat at full throttle and high rpm?

I'm not quite sure what the price on the oem cat is. I have only had the S out for about 15 miles since I installed it. I havent noticed any smoke when I get on it a little. What I didnt find was the same smell from the test pipe and that sand noise that sounds like you have an exhaust leak. I knew the sound woould be there, I just didnt know it would be so loud. I would highly recommend this as an alternative to a test pipe. Plus its OBDII compliant..........not that I have to worry about that in Colorado.

http://www.berktechnology.com/shop/product.asp?strParents=93&CAT_ID=100&P_ID=425

[repiv]

I'm not quite sure what the price on the oem cat is.
About 700 bucks. The Berk seems like a bargain.

[s2k 4 me]

About 700 bucks. The Berk seems like a bargain.

Wow, in that case its definately a good deal.

[dumbkid]

yea, guys... i'll look into that, now on to my new problem in my new thread... i'm frusstrated.

[repiv]

yea, guys... i'll look into that, now on to my new problem in my new thread... i'm frusstrated.

I saw that .................. :yikes:
You may have to change your username to "baddumbluckkid".

[dumbkid]

yea, i may do that... luckily that should be freebie and then some.