# P0420 code



## am3rican (Feb 26, 2005)

Hello Nissan Enthusiasts,

I searched for my problem and found a number of threads regarding the P0420 but not the specific problem I have had. I need some advice as to what to do.

I bought a 2001 Nissan Maxima SE 5spd with 33K in november. it was precertified and i also got an extended warranty to cover everything else. In december, my "service engine soon" light came on. I took it to the dealer and the P0420 code came up; they said my computer just needed to be reprogrammed. Well about the first week of Feb. the light came back on again! Same code and now they are telling me my fronttube assembly is leaky and needs to be replaced. its $717 for thr part and 200 for the labor. My car has 38K miles on it and it wont be covered under warranty. my question is, shouldnt this be covered under the federal emissions warranty, because from my understanding, it connects the header to the cat. if not, could i get a custom exhaust for cheaper? let me know, because i am strapped for cash and $900 seems like a lot for a metal tube


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## Matt93SE (Sep 17, 2003)

You have several options here, but none of them should cost you $900!!

first.. make sure it's not just a leaking gasket or a broken mounting bolt on one of the flanges. that's a $10 fix.

second.. if the pipe is cracked, see if it can be repaired at a muffler shop.

third.. if you need to replace it, you can buy a performance pipe for just a couple hundred bucks from many online places.. www.warpspeedperformance.com, www.cattman.com, www.stillen.com, etc.....


Just whatever you do, DO NOT PAY $900 TO FIX THIS!!!!!


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## am3rican (Feb 26, 2005)

Matt93SE said:


> You have several options here, but none of them should cost you $900!!
> 
> first.. make sure it's not just a leaking gasket or a broken mounting bolt on one of the flanges. that's a $10 fix.
> 
> ...


Im seriously having second thoughts buying this Nissan. I had a Honda before with absolutly no problems.


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## Matt93SE (Sep 17, 2003)

generally, they're just as reliable as a Honda.. My Maxima has 218,000 miles on it and I beat the [email protected])#(!)( out of it daily.

Nissan service is the big downfall. they're pricks and will deny everything under warranty the first time you take it in.


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## lshadoff (Nov 26, 2002)

According to the FSM the possible causes of P0420 are:

Three way catalyst (Manifold)
Exhaust tube (leak before the catalytic converter)
Intake air leaks (after the MAF)
Injectors
Injector leaks
Spark plug
Improper ignition timing

Ask the dealer if they went through the entire diagnostic procedure in the FSM and checked for intake leaks, the injectors, and ignition timing. An exhaust leak before the cat should be easily heard while the engine is idling.

Lew


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## am3rican (Feb 26, 2005)

lshadoff said:


> According to the FSM the possible causes of P0420 are:
> 
> Three way catalyst (Manifold)
> Exhaust tube (leak before the catalytic converter)
> ...


What kind of sound would the exhaust leak make? 

Update: told the dealer to go f**k themselves (in a polite way). anyways, they reset the code, and ive driven almost 100 miles today and the light hasnt come back on. im not sure if that means it wont come back on though. i think they (the dealer) missed the problem when i first took it in in december and now its come back.


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## NoKTournAL (Feb 11, 2003)

Matt93SE said:


> generally, they're just as reliable as a Honda.. My Maxima has 218,000 miles on it and I beat the [email protected])#(!)( out of it daily.
> 
> Nissan service is the big downfall. they're pricks and will deny everything under warranty the first time you take it in.


Really unnecessary comment, its people in certain dealerships that cause this bad representation.
I've helped countless Nissan enthusiasts with their issues, maintenance is their issue, and if I can help with an idle volume learn on the side for someone who just did a TB service, why not ???
Bump some timing, warranty oxygen sensors on a car with a Y-Pipe, c'mon, lets be realistic, and not generalize 'a' bad experience with ALL Nissan service centers.

BTW, love your products Matt 
Unique, and true enthusiast.


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