Heya guys,
Today out of nowhere I have had another CEL with:
P0420 - Powertrain
Catalyst System Efficiency Below Threshold (Bank 1)
WTF? I just got rid of P0300: After Ran Out Of Gas discussed at:
p0300-after-ran-out-of-gas-t621407.html
And now I have this one now, P0420.
Thank God, I passed my inspection on the last day of the month of expiration.
So at least I dont have to think about passing the inspection for another year. But anyway...
What possibly could go wrong?
Where to look for?
Thank you in advance,
siny240sx
P0420: Three Days After Fixing P0300
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far raf
- Posts: 213
- Joined: Tue Feb 21, 2017 2:53 pm
- Car: 2005 Nissan Quest SE (standard? simple? edition - i.e. nothing special)
Re: P0420: Three Days After Fixing P0300
It's about time you got this code, this means your rear pre-cat kicked the bucket. I have this code too, did a conditional pass this year and will have to worry about that before the next year inspection. The rear pre-cat on VQ overheats all its lifetime and eventually fails.
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siny240sx
- Posts: 60
- Joined: Wed Jul 04, 2007 11:25 am
- Car: 2007 Nissan Quest SE
1998 BMW 528i - Location: Staten Island, NY
- Contact:
Re: P0420: Three Days After Fixing P0300
Hey far raf,
What is it exactly?
Like part number or where is it located?
What is it exactly?
Like part number or where is it located?
Re: P0420: Three Days After Fixing P0300
Could be from extended running with the 300 code too. If you misfire long enough the cat has to overheat taking care of the extra unburned fuel, it then goes bad way early. The cats are made to not have to burn much at all and they overload very easy with any misfire going on, the temperatures run way up and they often internally melt the matrix inside then.
I used to see that all the time when I was in parts and on more than one brand of car. It can be death to run a cat with misfire even over a few minutes.
I used to see that all the time when I was in parts and on more than one brand of car. It can be death to run a cat with misfire even over a few minutes.
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siny240sx
- Posts: 60
- Joined: Wed Jul 04, 2007 11:25 am
- Car: 2007 Nissan Quest SE
1998 BMW 528i - Location: Staten Island, NY
- Contact:
Re: P0420: Three Days After Fixing P0300
Thanks amc49,amc49 wrote: ↑Wed Sep 05, 2018 1:53 amCould be from extended running with the 300 code too. If you misfire long enough the cat has to overheat taking care of the extra unburned fuel, it then goes bad way early. The cats are made to not have to burn much at all and they overload very easy with any misfire going on, the temperatures run way up and they often internally melt the matrix inside then.
I used to see that all the time when I was in parts and on more than one brand of car. It can be death to run a cat with misfire even over a few minutes.
Thats exactly what my friend mechanic says.
As a matter of fact he told me about possiblility of killing it when I just started to have that misfire.
And I drove for good number of miles like that. Close to 1k.
You live you learn...
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