2007 Honda Pilot Emissions and CEL - Help Please :)

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On my 2007 Honda Pilot AWD with AT - getting P0420 and CEL is on, randomly it goes away on it's own.

Cleared it up via battery terminal reset and back again after few hundred miles.

Now have to get the emissions done and can't do it because of this code.

Do I have to replace the CAT or would a fouler do the trick? Thank you.

 
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Could be the cat failing or you simply need a new o2 sensor.

If the cat is failing a fouler *might* work if all they’re doing is an OBDII test, but it’ll fail if they actually measure the exhaust gases.
 
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Since you specified "Murica" as your location I can only guess, as each jurisdiction is different.

Mine allows one un-finished monitor. CAT and EVAP are among the most complicated and they take the longest.

Anti-foulers do work quite well, but check the market for your used catalyst. Some honda ones are worth $600+, and it's legal in most places to put in an EPA-certified aftermarket cat. You could come out money ahead.
 
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I'd go the anti fouler route first. P0420's are as common as dirt with a Honda. My 2003 has thrown that code off and on for about 10 years now and I've never bothered to do anything about it since we don't live in an emissions county. If I did, it would be getting the fouler trick first thing.
 
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maverickfhs

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I'd go the anti fouler route first. P0420's are as common as dirt with a Honda. My 2003 has thrown that code off and on for about 10 years now and I've never bothered to do anything about it since we don't live in an emissions county. If I didn't it would be getting the fouler trick first thing.
Planning to do it now and use these ones: https://www.autozone.com/ignition-t...park-plug-non-foulers-2-pack-42009/730544_0_0

Should I use the gasket/washer on the fouler or no need for it? Thanks
 
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I hate to even say P0420. We got it XMAS day 2021. I reset, and 1300 miles later the car was in a I/M ready. Since inspection month is October, here in PA, we can inspect a month 10 car, in 8,9,10. So 2nd week in August we had it inspected and passed. Sure enough in October, P0420. Then, to add insult to injury, the other car, which needed a month 10 inspection, in October, P0051.

Anyway, reset car 1, and like 200 miles later P0420. I thought oh no, here we go--my experience is when resetting, and it comes right back, then problem.

Anway, reset yet again, and now, 796 miles later, I/M is ready. I am hoping there is some other factor, that throws the 420 other than cat defective. How does it go nearly one year and not come back? How does it today as I type, go 800 miles and not come back? I think for the heck of it, I'd get new 02 sensors up and downstream on the side that's throwing the code, just to see.

Problem as I see it--our GM car takes 800+ miles for the EVAP to be ready. A shop told me they can't pass it with that not ready, even though online it seems to say 1 category can be not ready. So unlike my other car, which goes back to I/M ready in < 80 miles, we can't easily reset and pass emissions.

Again, seems so many factors can trigger that P0420, seems wasteful to replace the CAT(s) right away.

I just wanted to share my experience with that code, it went away for almost a year upon a single reset, then came back in weeks, and is gone again hopefully past the next inspection date. Good luck

p.s. on our car I need to replace the plugs haven't gotten around to it--original at 111k, so maybe that will help, although I've never seen any improvement on the other 2 cars when I replaced plugs prior to recommended....

:)
 
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Again, seems so many factors can trigger that P0420, seems wasteful to replace the CAT(s) right away.
At the end of the day, if there are no exhaust leaks, there are no software updates for the condition and the af/o2 sensors are working properly, it needs a CAT.
 
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At the end of the day, if there are no exhaust leaks, there are no software updates for the condition and the af/o2 sensors are working properly, it needs a CAT.
Yes, but there's a lot to it as demonstrated on YouTube. It reminded me of a basement water scenario I had. A buddy said you really shouldn't call out a "pro," without first looking at it yourself. They really cannot come out "when" there's a torrential rainstorm--and that's exactly the time you want to look at it yourself, to find out where the water is coming in. If you call the pros, they go immediately to the $10,000 solution (french drain, sump, etc.)

I listened to that buddy, saw the water coming in a vertical crack in the basement, and found a $114 kit on amazon, watched a YouTube, and no more water issues. It was a kit that systematically injects urethane into the crack forever preventing water penetration. I would never have believed in a $114 solution when I was thinking $10k. Just googled it and wow, the same kit is $154 today. I look at P0420 the same way, we simply want to avoid throwing the baby out with the bathwater. But other than cost, it's fine to simply eliminate the issue by replacing everything that could potentially be the root cause.
 
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