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Good day all, I have a question regarding smog test that I could use some help on. I have an 2000 Acura RL that has had an error code for a while. The code is P0420. Anyway, I have not paid much attention to it, except, that I knew it would be an issue come smog time. I live in CA, which I know makes things even more difficult.
Anyway, having a code scanner, I went in a erased the error a day before the test. What I did not know at the time is that the act of erasing the code would cause in issue in itself on the smog test. It did.
Now, the interesting part is that the car passed the visual inspection and the emissions test but not the functional check. So according to the results, emissions were okay.
I now know that to pass, I would need to run the car through a cycle or two to retrain the computer. The problem is, anytime I do that the error code comes back. Usually, within 20 miles or so.
And did I mention that the smog technician did not even mention to me that my car failed. I had no idea until I got the DMV paperwork stating it instead of my tags.
So, anyone have any clues at what may be going on? I passed the emissions test so should my catalytic converter be good? I may ultimately take it in to the shop but I would like an idea on the possibilities to make sure they don’t pull the wool over my eyes.
Thanks.
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So it sounds like it passed a tailpipe emission check… I don’t know this for a fact, but I think I remember hearing or reading someplace that in California you can take it to a state alternate inspection station and if it passes tailpipe emissions then it would pass the test.
I am very familiar with this problem because Toyotas around your year would throw P0420’s wayyyyy too easy… They would easily pass tailpipe emissions tests but the ECU software had to be reflashed in several models so as not to throw the P0420 so easily.. Some of the older models did not get a re-flash and it makes it a big PITA when it comes to emissions. (Hence the need for an alternate inspection)
A new Cat should fix your problem, but I would look into the alternate test (if it exists or is internet rumor)…
Keep us posted.
-Karl
Thank you Karl. I do believe it is some kind of tail pipe test. At least, that it looks like to my eye. And from you post, it looks like I could be screwed into buying a new converter either way. Obviously, given the cost I am hoping to avoid that but if that is what it is, oh well.
Don’t know much about alternative testing but if the error code would still be a problem, then that likely won’t do much better. And yeah, if my issue is due to a sensitive ECU, then it is tough either way.
Quick follow-up question. I talked to a shop earlier that asked me to bring my smog results, which are good on emissions test. I assume they have some more sensitive equipment to further check the issue? Or will they simply recommend removing the converter regardless?
Since I specialize in Toyotas, I don’t really know if Acura/Honda ECU were this sensitive as well…
Without a doubt, any tech will tell you to get a new Cat if you need to pass an emissions test. It will get rid of the P0420 which will cause an automatic fail anywhere emissions are tested using solely an OBD II test…
As you have learned, the monitors have to be “READY” and a P0420 will cause them not to be ready. (thus just resetting the code will not work)..
The only reason I bring up the state alternate testing is that it may be a way to not have to repair the cat if the tailpipe emissions were within standard… Regardless of whether it is throwing a P0420 code… I think it would certainly be worth a look to see if this was true… I would check the internet and call whoever is responsible for testing within your state to see if it is true and can be done to save you some money…
Unfortunately many testing places only rely on the car to “tell on itself” using OBD II itself and don’t have an alternate program, leading to a repair which is not necessarily needed…
As a tech, I would say to get the repair if you are planning on keeping the car for a bit, because it will need it eventually and saves you some time and hassle…. As a frugal guy, I would see if there was a workaround…
JMHO
-Karl
Hondas are also picky about the P0420 codes, especially later models. In fact, they even pop up if you install a new aftermarket converter. If you want to confirm it’s operation this video might help.
I’ve been working on methods of cleaning catalytic converters but haven’t had success yet. I still have some more testing to do.
Keep us posted on your progress.
I just had the same issue, I lost a tremendous amount of power and after awhile I started getting misfire codes. It was my catalytic converter that was causing it all. I had my knock sensors go bad so I replaced those and my manifold gasket, about three days later I got the P0420 code. I took it to a local redneck muffler shop and 125$ later it was almost back to new. I do recommend if you have driven with that code for awhile that you check your manifold gasket for leaks or for any vacuum leak for that matter, spark plugs and wires, o2 sensors, and catalytic converter. Sometimes one thing can cause another which is what I believe happened to me.
i had this code on my sentra ,it said threshold bank 1 , it was the exhaust gasket manifold (front catalytic converter). replaced it code gone , smog passed . i got selected for the star program(CA) . which is total B.S. and has certain limits of smog i can’t go over and can’t have certain codes i can’t have and will not get my tags until the problem is fixed . so yeah gonna have to get a new catalytic converter to get your tags . btw since we live in CA you CANNOT buy a used one , it HAS to be new . unless you find someone that will pass all test aka crooked shop but will charge you lots probably 200$.
EDIT : you can also try to talk to the smog referee and work it out. my dads 05′ corolla was the same visual + emission passed but didn’t pass for some reason but he talked to the referee and they passed him .
Isn’t there a federal law/warranty that a cat should be good for 8 years or 80k miles– it’s a free replacement before then.
Just a thought.
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