How urgent is p0420?
04-07-2014 | 08:03 PM
#1
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How urgent is p0420?
P0420 code is being thrown. Will continuing to drive on it mess things up significantly. Going to be changing out the plugs and ignition coils as soon as I get them from mazmart. I know that won't fix the issue but will maybe help avoid it in future after fixed.
If it's clogged cat which I'll check when do ignition change, can I just gut it til I buy a new one. At least won't have a bad cat to help mess stuff up. Don't have emissions for a year and have always wanted to check out the gutted cat.
If it's clogged cat which I'll check when do ignition change, can I just gut it til I buy a new one. At least won't have a bad cat to help mess stuff up. Don't have emissions for a year and have always wanted to check out the gutted cat.
04-07-2014 | 08:23 PM
#2
The X is silent
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From: New Lebanon, Ohio
You have also to consider that this could be a bad 02 sensor. If the cat is clogged, you can gut it and your car will run fine, but you will continue to have a CEL and that same P0420 code. I would consider it a cause for action if I were you...
04-08-2014 | 08:06 AM
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Thanks for the replies. I am just going to gut the cat and change the ignition this weekend. Yea I'll have a code but at least it will be from me and I'll know why it's on. And I'll figure out the o2 sensor and replace if necessary
11-07-2018 | 10:20 PM
#5
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From: Las Vegas Nevada
P0420
i keep getting this cel and I replaced both 02 sensors, so I checked out the cat and it’s empty there is nothing inside . I put a BHR ignition system in and new starter and was getting a p0610 code so I replaced the ECM now I was driving it to get rid of the incomplete’s to Pass smog and the CEL came Back on with a p0420 I just spent $2500.00 and I don’t know what to do next can some one help me please ?
11-07-2018 | 11:10 PM
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If you have a gutted cat you will get a CEL. Only way to fix it is it replace the cat. New OEM is very expensive, I think it is either $1500 or $2500. People sell used ones on here for $2-300 pretty often.
11-07-2018 | 11:44 PM
#7
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From: Las Vegas Nevada
I didn’t gut the cat . I’m saying I never touched the cat except the one time that I took it off and there was nothing inside of it . I could shine a light right threw it . I have a 2004 with 111773 miles on it and I’m the only owner and the only one who has ever worked on it except for the dealer and they only did the recalls . Is it possible that it came empty from the dealership ? Could it be a Japan model ? I’m asking cause I don’t know .
11-08-2018 | 01:41 AM
#10
https://www.hottexhaust.com/Magnaflow_23909
you didnt bother to tell us were you are, but if you are in the usa that link will help. and if you try there is a 25% discount code to make it better.
beers
you didnt bother to tell us were you are, but if you are in the usa that link will help. and if you try there is a 25% discount code to make it better.
beers
11-08-2018 | 03:03 AM
#11
11-08-2018 | 09:54 AM
#12
I didn’t gut the cat . I’m saying I never touched the cat except the one time that I took it off and there was nothing inside of it . I could shine a light right threw it . I have a 2004 with 111773 miles on it and I’m the only owner and the only one who has ever worked on it except for the dealer and they only did the recalls . Is it possible that it came empty from the dealership ? Could it be a Japan model ? I’m asking cause I don’t know .
You might want to take it off and see if any pieces shake out, or at least crawl under it and try to bump it and listen for rattles.
11-09-2018 | 11:37 AM
#13
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From: Las Vegas Nevada
Thank you all for the help I live in Las Vegas NV and unfortunately I have California emissions so I had to buy the $908.00 magnaflow 546150 that was CARB compliant. My car is a Japan model and I think that the dealer put the sticker on the car for Cali emissions but never put the CARB compliant cat on the car . I’m not sure if they even use a cat in Japan because I had herd that in Japan they change the motors on there cars every 30,000 miles for emissions . If that is true then that could be the reason my car’s cat was empty . And the reason it’s passed smog all these years is at 40,000 miles Mazda replaced my engine because of the recall in 2009 and I hit about 40,000 miles on the new one in 2014 and shortly after that is when I started to have check engine lights come on and problems getting it smoged . But the CEL would go off on its own and I would smog it right away and not worrie about it till the next year . This year has been the biggest problem and now in the last month I have put $4000,00 in to it and I hope the new cat fixes the problem . I want to thank the RX8 club for your help and I will keep you posted on if the cat works .
11-09-2018 | 12:16 PM
#14
^^ Japan uses cats just like everyone else. There was also never a recall on engines, there was only extended warrranty, which means the previous engine actually failed, and usually where there is engine failure, there is ignition and cat failure also. If it passed emissions previously, then it had a cat. It's not possible to pass a sniffer without one.
So, as the previous poster stated, check your muffler and the rest exhaust system for pieces of the cat.
And on the subject of ignition failure, you need to make sure your coils have less than 25k miles on them to be safe. That's what kills cats. If yours are older than that, or unknown, I'd recommend replacing them before they kill your new cat.
Something is not adding up here, what were you charged $4000 for? Short of a new engine, nothing really costs that much when issues are properly diagnosed before parts replacement.
So, as the previous poster stated, check your muffler and the rest exhaust system for pieces of the cat.
And on the subject of ignition failure, you need to make sure your coils have less than 25k miles on them to be safe. That's what kills cats. If yours are older than that, or unknown, I'd recommend replacing them before they kill your new cat.
Something is not adding up here, what were you charged $4000 for? Short of a new engine, nothing really costs that much when issues are properly diagnosed before parts replacement.
11-09-2018 | 12:44 PM
#15
Smoking turbo yay
Joined: Apr 2017
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From: BC, Canada
Yeah, I went to Japan before and the air smells like smoke there.
JK. If anything, their emission standards are even stricter. For one thing, we don't pay tax based on engine displacement here(and Japanese government is smart enough to multiply the rotary engine's displacement by 2 for the displacement tax).
That's why big V8s are popular here while Kei cars are popular in Japan.
Anyway, check the ignition components like mentioned. Get OEM Revision C coils or some kind of D585 coil upgrade(like BHR).
Also, I am not sure if it's a good idea to keep running that cat outside of emission tests... If you drive hard often, I wouldn't be surprised if the things inside overheat and melt even if you have a healthy engine.
JK. If anything, their emission standards are even stricter. For one thing, we don't pay tax based on engine displacement here(and Japanese government is smart enough to multiply the rotary engine's displacement by 2 for the displacement tax).
That's why big V8s are popular here while Kei cars are popular in Japan.
Anyway, check the ignition components like mentioned. Get OEM Revision C coils or some kind of D585 coil upgrade(like BHR).
Also, I am not sure if it's a good idea to keep running that cat outside of emission tests... If you drive hard often, I wouldn't be surprised if the things inside overheat and melt even if you have a healthy engine.
11-09-2018 | 04:13 PM
#16
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From: Las Vegas Nevada
Look in not trying to argue with you but the exhaust is clean nothing rattling inside . The cat is empty and I have passed smog for 14 years . I never did anything to the cat and no one else but me has ever worked on it . I brought it to the dealer for recalls and the warranty engine swap . So please don’t tell me that it has to have the cat to pass because it has passed up until now . And the $4000.00 I spent was for the BHR IGNITION ,566.00 $1600.00 ECM , $988.00 for a new cat ,$120.00 both o2 sensors plus $180.00 for the upgraded starter and before the dealer replaced the ECM they flashed the old one and charged me $130.00 and screwed me on that . So it was only $3600.00 but feels like $4000.00
11-09-2018 | 04:29 PM
#18
I understand the frustration, but understand what we're saying. This isn't about you being wrong, itsi interpretation of the facts at hand. The cat didn't come empty from the factory, so somebody emptied it, or it shattered. This is fact. The intermittent P0420 sounds a lot like that failing cat.
You have BHR coils, so your new cat should be safe, so that's good.
The ECM and O2 sensors extremely probably didn't need to be replaced, because they essentially never need to be replaced. If the dealer charged you for this, and replacing the parts produced no improvement, then I would argue with the dealer to take those parts back.
You have BHR coils, so your new cat should be safe, so that's good.
The ECM and O2 sensors extremely probably didn't need to be replaced, because they essentially never need to be replaced. If the dealer charged you for this, and replacing the parts produced no improvement, then I would argue with the dealer to take those parts back.
11-09-2018 | 08:26 PM
#19
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From: Las Vegas Nevada
Thank you for your help the cat will be here tomorrow so I will let you know how it goes .Changing the ECM did fix the p0610 code that was coming up and the car runs great . Everything I have changed has made a lot of improvement in the way the car runs and I’m very pleased .i just find it crazy that once I fix one problem another one pops up instantly . You know what I mean ? I hope this is it cause I can’t afford anything else . Shoot I still have to register my car after this is said and done . Again thank you and sorry for my attitude!
11-10-2018 | 07:12 PM
#20
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From: Las Vegas Nevada
So I put the cat in and drove like 60 miles and I passed smog no CEL and everything looks good . I wish I knew what happened to the cat that was in the car but I am finally done fixing my RX8 problems and I hope it stays this way
11-19-2018 | 02:29 PM
#23
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From: Ontario,Canada
I suspect the dealer replaced the cat and gave you a broken one [possible] who knows what happens behind closed doors or someone changed it when you parked it somewhere ,Hmm I need a cat myself
Last edited by Rmazda8; 11-19-2018 at 02:33 PM.
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