P420 code 2002 Toyota Camry 4cyl

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Some history...in May 2013, the main catalytic converter unit that is part of the exhaust manifold went bad and was replaced. Two weeks ago, the secondary cat and pipe were replaced after it started metallic rattling noise (probably from core breaking apart). Secondary O2 sensor was replaced at the time, too. Now we're getting a P420 cat code check engine light. Plugs and PCV were changed 47K miles ago and air filter was changed this January. Daily driver 15 miles one way to work....mostly highway. Is the main cat bad again now after 23000 miles? Or could it be something else? Do not know if main O2 sensor was changed with main cat. Car gets good gas mileage (ave 27-30 but will get 33+/- on trips) and runs fine. Uses 1 to 1.5qt oil in 5000 miles. 147000 miles. Suggestions?
 
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There are MANY Toyotas with the P0420 code. My Sienna has the CEL on, it is the dreaded P0420 code. In the research I have done, the factory computer settings does not allow much degradation over time, so when the catalytic converter starts to age, it falls below threshold. That is what sets the light. If the shop went to Advance Auto, your cat is not stock, it is aftermarket. Again, based on my research stock parts last the longest, but are SIGNIFICANTLY more expensive. I have learned to drive with the CEL on, I have a Scangauge, so when I get sick of looking at the light, I clear the code and it comes back in 100-150 miles. I don't plan on fixing my van, I live in a non emissions testing state, so I am not going to spend the money to address this issue. I personally feel this should be a recall. I like my Sienna, but the CEL on all the time is annoying. It may be time to get out some black electrical tape to cover the light
 

little bob

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Thanks...will do. I think the main cat is a Walker based on price charged earlier and photo on the AAP website. Is Walker stuff good? Would changing plugs and PCV possibly help?
 

little bob

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Unfortunately, NC is an emissions state for newer cars/trucks(<1995?) so we'll have to get it fixed before the next inspection.
 
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Walker has the same issue with Subarus.After 6 months the light comes back on.Been told you need OEM converter or a reflash at the dealer to allow an aftermarket cat (don't know if that's possible or not).Frankly,aftermarket stuff like that is generally cheap and not made well (so it can be "cheaper").
 
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Aftermarket cats are not a great solution, but they are better than nothing when you have to pass a state inspection. A coworker of mine has the same issue with his Grand Prix. Walker cat lasted about a year before its efficiency fell below threshold. The OEM cat prices are totally justifiable when you consider the difference in longevity.
 
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Have you tried spark plug extenders on the post-cat O2 sensors? It may get the sensor out of the stream enough to satisfy the computer, but still looks stock enough to pass most visual inspections.
 

little bob

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Supposedly, the Walker cat has a 5 year warranty. Even though we've treated and maintained the car well, I assume that they'll find some way not to honor it
 

little bob

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On the post cat O2 sensor...Dont know what the shop did other than swap the old one out for another. I'll check on whether all the stuff used was OEM or not. The inspection has to be done before next Feb so we have time to save our pennies to get the stuff fixed. I'll also check with the shop to see if they can reflash the computer for the aftermarket cat. Thanks guys.....
 

JC1

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Originally Posted By: DutchBrad
There are MANY Toyotas with the P0420 code. My Sienna has the CEL on, it is the dreaded P0420 code. In the research I have done, the factory computer settings does not allow much degradation over time, so when the catalytic converter starts to age, it falls below threshold. That is what sets the light. If the shop went to Advance Auto, your cat is not stock, it is aftermarket. Again, based on my research stock parts last the longest, but are SIGNIFICANTLY more expensive. I have learned to drive with the CEL on, I have a Scangauge, so when I get sick of looking at the light, I clear the code and it comes back in 100-150 miles. I don't plan on fixing my van, I live in a non emissions testing state, so I am not going to spend the money to address this issue. I personally feel this should be a recall. I like my Sienna, but the CEL on all the time is annoying. It may be time to get out some black electrical tape to cover the light
I get the same P0420 on my 98 Sienna. Sometimes it stays off for weeks, other times, primarily in colder weather it can come back on after a few days. I just reset it with my scanner. Once you switch to an non OEM cat on a Toyota this issue with persist. Do you have emissions testing where you live? In Ontario we have emissions testing, but I'm usually ok, since I can reset the check engine light a few days before the test and it always passes. I'm not going to spend $1300 on an OEM Toyota cat to pass an emissions test on a 16 year old vehicle. Regards, JC.
 
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Originally Posted By: little bob
Unfortunately, NC is an emissions state for newer cars/trucks(<1995?) so we'll have to get it fixed before the next inspection.
why not just clear the code right before you take it in to be inspected?
 
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Originally Posted By: JC1
In Ontario we have emissions testing, Regards, JC.
What's an emissions test? No such thing for passenger vehicles in Northern Ontario, you know - north of Toronto / GTA ... cool
 
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Originally Posted By: Barkleymut
Originally Posted By: little bob
Unfortunately, NC is an emissions state for newer cars/trucks(<1995?) so we'll have to get it fixed before the next inspection.
why not just clear the code right before you take it in to be inspected?
the computer knows.thats in instant fail here
 
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Originally Posted By: javacontour
Have you tried spark plug extenders on the post-cat O2 sensors? It may get the sensor out of the stream enough to satisfy the computer, but still looks stock enough to pass most visual inspections.
Seems people would rather do things the hard and more expensive way. The extender would probably fix 90% of P420 codes, but people would rather replace a cat, and then have the same problem... crazy
 
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