Has anyone experience a bad OEM converter and replace it with an After Market but still shows P0420 code. I replaced mine twice with a after market converter and it still shows P0420. I have replaced both o2 sensors and still doesn't change the status. I'm wondering if it just needs to be the OEM from the dealership. I just really don't want to spend 3 times as much for it, but will if that fixes the problem in the end.

Did you try having the code reset after installing the new cat?

i've replaced my cat to a short body ceramic, no code thrown. i think you need to clear the code.



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The code was clear each time. Once when the first CAT was installed. Second when the second CAT was installed. Third when both o2 sensors were replaced. And forth was to just clear it again. After each time it was cleared it came back on 100-200 miles later.

try the manual sim.



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Aren't those sensor sims illegal?
I guess for a race car they aren't illegal, but I am guessing since he is trying to put a cat on, this is not for a race car.

Have you tried using spark plug defoulers? It will keep the sensor far away enough to prevent the code. Well known trick in the VW world. If you are in a emissions state just remove the defoulers come test time.

Wouldn't the test still notice there is something wrong? I have FL tags currently, but want to give it to someone in PA which I believe is an emission state

yes, PA is an OBD 2 emissions state. However, with that there is NO visual emissions inspection (besides gas cap). So pretty much as long as your check engine light works properly, and there are no codes, and most of your readiness monitors are set....you pass.

o2 sim, or otherwise.

let me know if the o2 simulator works, and where/how much you get it for...ive heard some poeple say about just spacing out your 02 sensor..i dono if it works or not tho


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I heard about the o2 sim before but I'm not sure I want to spend $150 just to find out it doesn't work.

From what I've read on here, sometimes the O2 sims work, sometimes they don't. The spark plug anti-fouler trick seems to work pretty efficiantly and is much cheeper. Just drill the center out of an anti-fouler to fit the O2 sensor and screw it onto the sensor, screw a second anti-fouler into the sensor bung and scew the the first Anti- fouler/O2 sensor into the second. It slows the reading respose enough that the PCM thinks the O2 is working.

how bout you say what cat you're using.



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- Sold my beloved J in April 2010 -

I just bought the foulers. I will install tomorrow. Reading so much info on this last night I'm excited and wish I would have came across this earlier. I'm using an Easterns CAT