Check engine code P0420 comes on and off
#1
Intermediate
Thread Starter
Check engine code P0420 comes on and off
Hi guys I have a Acura TL type s 2007 with 220k on it. It's drives like brand new and lucky no problems besides regular maintence which I am very on top of. Always use 93 gas from big name brand gas places Mobil, shell, Sunoco etc. the problem is my check engine light comes on every so often with this code and then after let's say 2 days or less goes away. I know it's a cat converter code I think bank 2 but not sure on that. My question is do you think it's my o2 sensor that's needs to be replaced or the cat itself or something else any help would be appreciated thanks guys
#3
Intermediate
Thread Starter
Thanks for the quick response! Could it be that the sensor might be lose or maybe its just on its way out lol. One question i have though its that those codes come up based on the the 1st o2 and the next O2 after the cat so if its not reading correctly then could it be the Cat? I mean it must be hard to tell if its really the cat or the sensor cause the cat itself is not connected to the ECU. I'm not to good on which bank is which and which sensor is sensor. Its there a cut away diagram anyone got handy be greatly appreciated. Thanks.
#4
Senior Moderator
yes very well maybe the Cat. Got the same code on my older accord. Read all around and it said maybe o2 but definitely cat. I replaced cat for 600.. no more code. 02 sensors were fine . 260K still same o2 sensors.
#5
Suzuka Master
its better to spend $120 on a sensor and worry later one rather than spend $900 for a cat and the the CEL still on.
#6
Suzuka Master
if it is turning itself off I wouldn't spend anything yet
#7
Senior Moderator
Hi guys I have a Acura TL type s 2007 with 220k on it. It's drives like brand new and lucky no problems besides regular maintence which I am very on top of. Always use 93 gas from big name brand gas places Mobil, shell, Sunoco etc. the problem is my check engine light comes on every so often with this code and then after let's say 2 days or less goes away. I know it's a cat converter code I think bank 2 but not sure on that. My question is do you think it's my o2 sensor that's needs to be replaced or the cat itself or something else any help would be appreciated thanks guys
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#8
Intermediate
Thread Starter
Thank you all for your responses so far. Csmenace i will try the fuel injection cleaner i usually use techron. Not a huge fan of seafoam to be honest but if the Techron doesn't work i will try it on the gas take only. I also wanted to give a update on this i haven't been able to lift the car up and look underneath anything. However after some testing i realized that the code mostly comes on after i have pushed the car which i rarely any more with the miles on it im trying to cruise it and play safe and after driving it around for a day or two goes away. I find this unusually but leading me to think it is a going to be soon failing cat.
#9
Intermediate
Thread Starter
Hi all, Just a update i got a bottle of seafoam i dont plan on running through the engine and vac line but will use it in the gas tank. I will also be using shell gas or mobil for the next couple of weeks to try get as much detergents in the system as possible. I do think its a clogged Cat and hopefully somehow it can reach the Cat which i am not to certain it will because the more i think about it when the gas burns itself doesn't it lose all it detergents in it. basically its a miniature explosion in the piston. So can the detergents survive that explosion and heat? Or am i thinking the wrong way on this idea.
#10
Suzuka Master
If you cat are failing it will throw another code along with P0420.
#11
Moderator
iTrader: (1)
to understand what is failing and how to fix it, you have to understand what each individual parts do.
a catalytic converter is made up of precious metals. it has a ceramic substrate in the shape of honey combs.
when you use poor fuels and run the tank dry, you damage the catalytic converters.
this honey comb substrate falls off and clogs the cat.
you will not be able to clean a clog cat by running better fuel, detergent or a cleaning agent like seafoam, because a piece of substrate is blocking the insides of the cat.
the only way to fix is is to remove the cat and either take out all the substrate or replace the cat with a new one
a catalytic converter is made up of precious metals. it has a ceramic substrate in the shape of honey combs.
when you use poor fuels and run the tank dry, you damage the catalytic converters.
this honey comb substrate falls off and clogs the cat.
you will not be able to clean a clog cat by running better fuel, detergent or a cleaning agent like seafoam, because a piece of substrate is blocking the insides of the cat.
the only way to fix is is to remove the cat and either take out all the substrate or replace the cat with a new one
#12
Registered Bunny
to understand what is failing and how to fix it, you have to understand what each individual parts do.
a catalytic converter is made up of precious metals. it has a ceramic substrate in the shape of honey combs.
when you use poor fuels and run the tank dry, you damage the catalytic converters.
this honey comb substrate falls off and clogs the cat.
you will not be able to clean a clog cat by running better fuel, detergent or a cleaning agent like seafoam, because a piece of substrate is blocking the insides of the cat.
the only way to fix is is to remove the cat and either take out all the substrate or replace the cat with a new one
a catalytic converter is made up of precious metals. it has a ceramic substrate in the shape of honey combs.
when you use poor fuels and run the tank dry, you damage the catalytic converters.
this honey comb substrate falls off and clogs the cat.
you will not be able to clean a clog cat by running better fuel, detergent or a cleaning agent like seafoam, because a piece of substrate is blocking the insides of the cat.
the only way to fix is is to remove the cat and either take out all the substrate or replace the cat with a new one
Ghetto'est.
#13
Intermediate
Thread Starter
Hi all just wanted to give a update on this. So i abandoned my plan using seafoam i instead used something i trust more Chervon Techron with a combination of Shell V-power nitro gas. I had this light on for about 1 week was not going away i was using cheap Pilot gas in NJ. After about half a tank later the light went away by itself and so far the light has not come back on. I plan to still use the shell gas for now and i get a great price here next to my house in N.Y upstate 2.89 per gallon not to bad. My main concern is i might have a more underlying problem thats i want to take care of before it becomes a big issue. I want to hopefully keep this car as long as i can 300k+ as daily driver. I dont like the TLX to be honest and our double wishbone suspension gone I change the spark plugs etc and did my 200,000 mile tune up. Do you think bad or dirty injectors can cause this light? also i never replaced injectors in any Honda/Acura i ever had and all went 200k easy. Thanks all for listening to my Rant and any help or knowledge would be great/
#14
3rd Gear
Join Date: Aug 2015
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I was having the same issue for about 3 weeks, The check engine light would come on and go off. I was getting the same code. I ended up using some seafoam in my gas and the check engine light went away and hasn't came back.
#15
Suzuka Master
use top tier gas and you won't need seafoam bs.
#16
HASTA LA VICTORIA'
Funny I just ran into this. I am also going through the same situation.I got the same code come up last year and it went away after a few days of driving, so I think it's the gas. I had to fill up outside of my normal town and found a rundown gas station but 93 gas was cheap.. So yea.. Good luck. I am trying Seafoam today...
Last edited by cipdagr3at; 10-29-2015 at 12:44 PM.
#18
Safety Car
iTrader: (8)
Reviving this thread
P0420 and P0430 comes and goes. I use 93 octane from Shell Exxon or Chevron. Only difference I have to the above is I have HFPC. I replace all 4 02 sensors about 15 months ago. Might have to pull them off and inspect them. Seafoam seems like a temporary fix
P0420 and P0430 comes and goes. I use 93 octane from Shell Exxon or Chevron. Only difference I have to the above is I have HFPC. I replace all 4 02 sensors about 15 months ago. Might have to pull them off and inspect them. Seafoam seems like a temporary fix
#19
Catalytic converters don't last forever. I also wouldn't change them unless you're losing power from restricted flow. If you have emissions requirements, either wait for the light to clear itself or go in with the catalyst monitor not ready.
#20
Drifting
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Well, the good thing is that those codes don't affect the engine in any detrimental way. They're just measuring catalytic converter efficiency. I have the HFPC's as well and Bank 2 comes on probably every couple of months or so. I replaced the sensor but no change. I just clear it and call it a day.
How often does it come on? And it's both of them? That kind of signals to me that there's something funky with the actual exhaust. Are you consuming oil or running lean/rich?
How often does it come on? And it's both of them? That kind of signals to me that there's something funky with the actual exhaust. Are you consuming oil or running lean/rich?
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