P0420 SOS

Gabriel Aug 18, 2019

  1. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    Help
    So my X finally popped the check engine light one for the first time
    3 codes all the same one P0240
    Catalyst Converter.
    So how do I diagnosed this?
    Im at 108k it seems to soon to go out? Right? Wrong? I dont want to replace it and that wasnt the issues.
    Guy at autozone suggested 93 gas and a gas cleaner so i was thinking seafoam and see what happens.
    Any other suggestions ??

    I read through the forum
    I found Replace
    O2s
    SparkPlugs
    Before I bother with actual catalyst (2)
     
  2. jsexton

    jsexton First Fill-Up (of many) Supporting Member

    Messages:
    379
    Location:
    Lewis Center, OH
    P0420 almost always means bad primary cat (I don’t remember which side is 420 vs 430 off the top of my head). I’d replace both sides at once.
     
  3. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    I wonder?!
    How long can i run it until it gives me issues running? Cause its my daily driver?
     
  4. jsexton

    jsexton First Fill-Up (of many) Supporting Member

    Messages:
    379
    Location:
    Lewis Center, OH
    I wouldn’t go long. These cats break up and can pull particles back into the engine taking out the rings. You don’t want that. Not a guarantee but it happens a lot more than it should.
     
    BCBrian likes this.
  5. TerryD

    TerryD Bumpers Installed Supporting Member

    Messages:
    1,068
    Location:
    Covington, Va
    The catalytic converters are a pretty common failure on the 2nd gen Xterra. They have a few failure modes though.

    The most common is simply wear. The catalyst gets to where it can't perform its duty. Get a bluetooth OBD dongle from Amazon for about $20 and the Torque app from the Play store. Monitor the down stream O2 sensor voltages. They will be different from side to side and I cannot remember the reason for that at the moment, but what you are looking for is them to be very erratic while the engine is under steady load, like interstate speeds with the cruise control set holding a steady speed.

    This is a good indication that your cats are aging and nearing the end of their lives. I think there's a video on Youtube that shows the changes before and after new cats in an Xterra.

    There is a second failure mode that's a little more severe. This involves the catalyst material in the converters breaking apart. Initially you'll get the same codes as if the converters are just aging, however in short order, sometimes mere miles from the initial code popping up, the material begins falling out of the case and can plug the secondary cats. At this point, best case scenario is simply bogging down the engine and loss of power. It can in some instances plug it enough for the pressure wave from the exhaust stroke mixed with the EGR function of the cam shafts causes the ceramic catalyst material to enter the cylinders, mainly the rear one on the side that's failing, and just grind the rings and cylinder walls away. That's a death sentence for the engine.

    So be leery of running the thing too much before pulling the cats and have a look at them and make sure they aren't coming apart on the inside. The cats aren't very difficult to pull and it's a good idea to get them out and checked.

    As for the plugs and O2 sensors, changing them probably wouldn't be a bad idea just due to age. At 180k miles those sensors have been subjected to a lot of heat and vibration and things like that wear like anything else.
     
  6. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    Any recommendations on where to get it from? I checked Rock Auto and apparently none of those are carb compliant for California. Since at some point i will return or will need to resmog.
     
  7. TerryD

    TerryD Bumpers Installed Supporting Member

    Messages:
    1,068
    Location:
    Covington, Va
    I was thinking the Eastern cats were CARB compliant or they had a compliant version. Anyways...

    I went with the Magnaflo and for the price, I was not impressed with the fitment. One came without the bolts, they came with the wrong gaskets, and one had the sealing surface cut so deep it took two factory gaskets to get it to seal on the downstream end.

    If I have to do mine again, which I really don't want to have to do again, I will be going with OE. Even with the insane pricetag, they are better. My OEs were just beginning to show signs of failing when I changed them but it was about a month after @jsexton had his lunch his engine at about the same mileage as mine had on it.

    I've had the full run of Xterra failures to that point with SMOD, the timing tensioners and the cam sensors. I didn't feel like gambling $4k on an engine for $600 in cats with the plan to do long distance travel in it.
     
  8. Zack.

    Zack. Bought an X Supporting Member

    Messages:
    107
    Location:
    Livermore, CA
    I got the Magnaflow CARB compliant ones (all 4), shop had to cut and re-weld the flanges on the exhaust pipes to fit. I had to replace the gaskets myself with crushable graphite ones to eliminate leaks.

    Bought the primaries through CarId with an amazon price match when they were cheap on amazon. I bought the secondaries through an eBay seller when there was a 20% off coupon.
     
  9. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    Magna Flow 558665/558668 right?
    I looked it up but for the Xterra its 05-11 so doesn't fit my 12. So I'm back in square 1. MagnaFlow site says its still under development.
    Any other ideas out there?
     
  10. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    Trying to avoid welding it on.
    I prefer the bolt on ones. Just need to ensure its beep beep beep beep California carb legal fitment
     
  11. IM1RU

    IM1RU First Fill-Up (of many) Supporting Member

    Messages:
    352
    Location:
    SLC, UT
    I find that hard to believe. Nothing changed from '11 to'12.
     
  12. TerryD

    TerryD Bumpers Installed Supporting Member

    Messages:
    1,068
    Location:
    Covington, Va
    I think MF just didn't update their listings since they discontinued the X. Might check Frontier listings. Same stuff.
     
  13. meisanerd

    meisanerd Bought an X

    Messages:
    101
    Location:
    Edmonton, AB, Canada
    As far as I have seen, the only Cali-friendly ones are the Magnaflows and OEM. Magnaflows seem to have fitment issues (as referenced above), OEM are just stupidly expensive, but seem to last significantly longer than any of the other cats.
     
  14. 29erClan

    29erClan Test Drive Supporting Member

    Messages:
    39
    I just ordered a set of Walker CARB cats for the 06 pathy. She was not happy that the sticker under my hood says federal, hers says Cali with some compliance numbers, and they do inspections around here. They even ask for the receipt for that crap. PITA. Thankfully my X isn't legal in Cali...

    Anyway, parts:
    WALKER 83698
    WALKER 83892
    WALKER 83699
    WALKER 83893
    were listed on rockauto as CARB-compliant to the spec on the sticker.

    The owner is biting the bullet after I've exhausted every other possible cause of the 420/430 over a few months. (Time to pass inspection...) Almost anything between the intake and the 2nd sensor can cause the code - it is not always a bad cat. Mine had cracks in the old intake boots after the MAF sensor and some flange bolts had worked loose. A little toyota had a blown out gasket between the primary and secondary. Both reported the code and both were fixed without buying new cats.

    That 06 pathy is another story. That exhaust is about to blow away in a cloud of rusty dust like that mummy movie when the good guys finally win. I was checking the flange gaskets and my fingers went through the pipe wall. Sometimes you just need new steel.
     
  15. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    So now the thing is
    2012 Xterra S
    Cant find the mangaflow cat anywhere the magnaflow site us out of stock.
    Reading more into it everyone says Frontiers are interchangeable when its comes to engine parts. I see 12-13-14 Frontier cats on the site? Would that work on my X with no issues or huge modifications?
     
  16. TerryD

    TerryD Bumpers Installed Supporting Member

    Messages:
    1,068
    Location:
    Covington, Va
    They're the same parts. They will bolt right up.
     
    Last edited: Aug 20, 2019
  17. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    Will not right up?
     
  18. TerryD

    TerryD Bumpers Installed Supporting Member

    Messages:
    1,068
    Location:
    Covington, Va
    Bolt. Fixed it.
     
  19. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
  20. General_Tarfun

    General_Tarfun First Fill-Up (of many)

    Messages:
    267
  21. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    So i called the stealership and umm 2 legs and an eye. $770 a side plus taxes. Sooooo

    Alternatives?!

    Has anyone actually done the frontier magnaflow on the Xterra, I just can't see myself dropping that much on a catalytic converter at this time.
     
  22. General_Tarfun

    General_Tarfun First Fill-Up (of many)

    Messages:
    267


    IMO only go with the Nissan cats if you plan on keeping the truck until the wheels fall off. They're a little cheaper from Courtesy Parts at $576 each + $190 core charge refunded when you send your old set back.

    The Magnaflows will probably work fine, just expect that you might have to work with them a little to get them to fit exactly, might need some extra crush washers, etc.
     
  23. TerryD

    TerryD Bumpers Installed Supporting Member

    Messages:
    1,068
    Location:
    Covington, Va
    I don't know of anyone having performance issues with the MF yet. I've got 19k on mine right now without issue. Just the aggravation getting them installed
     
  24. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
  25. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    Soooo

    For those seasoned crawlers
    $800 for the (2) MagnaFlow carb legal catalytic converters & (2) O2 sensors.

    Or

    Drop the whole set up to avoid future issues.
    $2800 for (4) MagnaFlow carb legal catalytic converters(front&rears) & (2) O2 sensors, afe carb short headers and afe carb exhaust system.

    Thoughts please.
     
  26. TerryD

    TerryD Bumpers Installed Supporting Member

    Messages:
    1,068
    Location:
    Covington, Va
    I did the two primary cats and O2 sensors. If your exhaust system is in good shape otherwise, there are minimal gains to be had from an exhaust system on these things...
     
  27. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    Well i just dont wana run into issues later on, exhaust is okay but still has that stock Y inlet?
    Headers are right there so why not gut it. Just thinking long term not having to do any repairs for a while

    Not to mention my fear of a screw not wanting to break and snap off or something and just being stuck mid repair.
     
  28. TerryD

    TerryD Bumpers Installed Supporting Member

    Messages:
    1,068
    Location:
    Covington, Va
    I get that. Luckily the studs on the cats are in the cat flange so if you break one, you're changing that part anyways.

    If the OE system is still in good shape, I wouldn't take it off. My system is 12 years old and has 190k miles and is still in good shape. Aftermarket stuff won't live that long.
     
  29. General_Tarfun

    General_Tarfun First Fill-Up (of many)

    Messages:
    267
    ^ Agreed, the original system holds up pretty well over time as long as you're not driving in a place where they heavily salt the roads. IMO I wouldn't replace the entire system at that price, it's too expensive for very little gain. I wouldn't even replace the sensors yet if I were you, I'd put in two Nissan primaries, straight pipe the secondaries and only then if I got a code would I replace the sensors. I'm still running the originals on my 06 with 168k miles without any issues.
     
  30. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    Interesting
    I appreciate everyone's thought

    So I'm guessing noone here has aftermarket headers or exhaust
     
  31. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    Im trying to get any input from someone that has magnaflow catalytic converters. Are heat shields needed? They are stainless steel so idk. Thars whats stopping me now. Thoughts please.
    The thing about heating up for a catalytic converter and lighting high grass. Its kinda high and have a skid on at all times so thoughts please.
     
  32. TerryD

    TerryD Bumpers Installed Supporting Member

    Messages:
    1,068
    Location:
    Covington, Va
    I have the Magnaflow primaries on my 2nd gen. They are high enough it wouldn't be too big a deal.

    I try to avoid parking over tall grass if I can help it but don't worry much about it.
     
  33. Gabriel

    Gabriel Test Drive

    Messages:
    29
    Location:
    Stafford,VA
    They should be going in this veteran's day weekend. Did you have any fitment issues? I purchased Remflex material, (to cut perfect size) To put in gaskets if needed.
     
  34. TerryD

    TerryD Bumpers Installed Supporting Member

    Messages:
    1,068
    Location:
    Covington, Va
    I had to buy OE gaskets for mine and you have to do some heat shield bending around the O2 sensors. The gaskets they came with wouldn't even begin to seal. I actually had to stack two OE gaskets on the rear of the driver's side cat to get it to seal finally but I have had no issues since then from them. I'd have to look back to see how many miles I've put on them but it's been about 15k I'd imagine.
     
  35. TerryD

    TerryD Bumpers Installed Supporting Member

    Messages:
    1,068
    Location:
    Covington, Va
    Well, as of Tuesday, I now have a Bank 1 Catalyst Efficiency code. Kinda pissing me off since these Magnaflow cats are only about a year and a half old and have about 20k on them.

    My first thought was that one of my down stream O2 sensors was dying. To check that, I swapped my down stream sensors this evening after work. They are the same sensor but they have different plugs for some reason. I took my pocket knife and trimmed off the alignment piece on the side of both connectors that didn't match up from side to side. In later years, they apparently just simplified this and used the same part number for both sides where as on the 07, they are listed as two different sensors. Anyways, that sucked but I got it done and it didn't make any difference. I'm still getting sharp measurement dives while driving. It hasn't set the code as of yet and I'm going to fill it up with some BP gas tomorrow (used Pilot/Flying J all weekend traveling) and then drive it a while and see how it goes.

    My upstream O2s went in when the cats did and are both acting similar to one another so I don't think there's an issue there. My LTFT was 3-4% higher on B1 than B2 so I cleaned my MAF (why that would affect one bank and not the other I have no idea, but it needed it regardless) and forced a LTFT reset to see what that would do.

    I'm going to be livid if these $300 cats are only going to last a year. And my OE cats went to the recycler so if I have to buy OEM cats I'm going to be out the deposit.

    GRRR
     
  36. 29erClan

    29erClan Test Drive Supporting Member

    Messages:
    39
    Since you mentioned the gaskets and needing 2, have you checked for new leaks? I struggled with that until I got some "sensor safe" exhaust paste gunk to seal up the gaskets better. You did the double gaskets about a year ago? (if I follow right)
     

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