P0420 please help :(

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Colton1er, Mar 23, 2018.

  1. Colton1er

    Colton1er New Member

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    Hey guys -

    My check engine light has been coming and going for about a year now - the only code being p0420. I’ve tried Seafoam, Cataclean, Techron, yada yada. Sometimes it stays off for a month with no problems, but it always comes back. I have averaged about 41mpg in the 18 months of owning the car.

    About a week ago I hopped in the car and drove about 500 yards and BOOM - my dashboard lit up like a Christmas tree. Check engine light, tire pressure, VSC, red triangle w/ exclamation, and also my LCD has a little red car with an exclamation point and said “problem”. Needless to say, I turned around and parked the car right away, pulled the code and again it was only p0420, nothing else.

    Is my cat completely clogged? Anyone have any suggestions?

    ***I should mention that my girlfriend drove the car last before this happened and she mentioned that she thought that she had to press on the gas pedal harder in order for the car to get going, and that it sounded like the engine was working harder than normal. Also, we live in San Francisco (there are a lot of hills) so that could have something to do with it.

    I drove to 3 local pick n pulls before doing some research and realizing it’s illegal to sell used CAT’s in CA. Toyota dealer wants $2.4k :( yikes. I’ve been scanning Craigslist for parts cars in Northern CA but they’re few and far between.

    If anyone has any input I would greatly apppreciate it.

    Thanks,
    Colton
     
  2. Mavi

    Mavi Active Member

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  3. Colton1er

    Colton1er New Member

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    Hey Mavi-

    Thanks for your response. I’ve seen people do this before - it’s the spark plug housing trick. From my understanding this tricks the oxygen sensor into thinking that the cat is operating correctly? I thought about giving it a shot, but was not sure if it was too late.
     
  4. exstudent

    exstudent Senior Member

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    What code reader did you use?

    Your car is 12yrs old and probably has A LOT of miles.

    CAT is probably dead/dying due to years of oil consumption. The Gen2s are known to burn oil. Excessive oil consumption will lead to an early CAT death. Do you know how much oil the car consumes between oil changes? If the car is burning a lot of oil, this will kill the replacement CAT quickly; essentially you will need to resolve the oil consumption.

    All those additives are a gimmick and just enrich the manufacture's of the snake oil.

    STOP wasting your money on gimmicks. The ECU will detect something is amiss and will throw a code some time later.

    You live in SF. Take your car to Luscious (SF) or Art's Automotive (Berkeley) for a proper assessment and repair options.

    CARB Cats are expensive b/c the manufactures have to certify that the replacement converter is as efficient as the OEM, and they must also provide a longer warranty. This longer warranty is the reason CARB Cats are expensive.

    Some people just do a bolt-on/weld-on Cat. Don't be surprised if the cat does not last long. I remember one person went this route, and the Cat only lasted a year.
     
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  5. Colton1er

    Colton1er New Member

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    Exstudent - thanks for your response. I used an auto zone obd2 both times.

    I’m not sure how much oil I’m burning between changes, because I don’t do the changes. I’ve taken it to the same garage every time and he’s never mentioned anything about an unusual amount of oil being burned.

    Isn’t an OEM cat the only option in California? Will Luscious or Art’s be able to provide that?
     
  6. fotomoto

    fotomoto Senior Member

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    Those readers don't always see the Toyota/hybrid specific codes but only generic OBD codes common to all cars (like the p0420). If you're still on the original HV battery, the lack of power and additional warning lights/codes could be caused by it.
     
  7. Colton1er

    Colton1er New Member

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    I was told that the HV battery was replaced before I bought the car, I believe I have paper work somewhere. Didn’t think this was a battery issue.
     
  8. fotomoto

    fotomoto Senior Member

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    Yeah find out if it's a genuine Toyota battery or an aftermarket unit. Lots of issues with those rebuilt packs. Anyway, get the codes read with a good reader. Those companies mentioned have very good reps.
     
  9. valde3

    valde3 Senior Member

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    That’s very bad. Why would they check how much oil is in the engine before changing it? So your engine could be using a lots of oil and get damaged and you won’t even know about it. It’s owners responsibility to check the oil level. Owner’s manual will tell you that and how to check it. Why do so many people just fail to check it?

    Any place is able to fit Toyota OEM catalytic converter as Toyota does sell it as a part.
     
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  10. Sam Spade

    Sam Spade Senior Member

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    WHAT ??
    You do know that you can check the oil yourself.....right ?
    And you really SHOULD do that at least a couple of times between changes.
     
  11. audiodave

    audiodave Active Member

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    The rear O2 sensor could be off or it could be the cat. I had a new dual cat assembly sent to a friend out of state than shipped to me.

    Posted via the PriusChat mobile app.
     
  12. Mavi

    Mavi Active Member

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    also if youre under 150k miles the dealer will change them under warranty! 15 years/150k.
     
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  13. SFO

    SFO Senior Member

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    Welcome to PriusChat!!

    How many miles on this vehicle?

    If you don't know much about the vehicles history (service, repair, owners, etc), you can look some of that up by registering the VIN at : Toyota Owners Official Web Site

    And the link for owner related manuals : Toyota Online Owners Manuals and Warranty

    It sounds like you may need access to a better code reader, as you may not be reading all of them.

    Were there any other codes read?

    Are you clearing the code(s) after each reading?

    On a side note, if the 'oil can' warning light hasn't been seen on the dash you could be ok (except for the previous owner). Either way it might be time to start checking the oil between changes. How often do you have the oil checked/changed, and what type of oil is used? (oil with a lower 'SAPS' can potentially extend the life of a cat)

    Yes, the OEM cat is the only legal option in CA (or NY) that I know of. You might be able to get away with finding and installing a used cat. I saw one for sale locally online, but it could just be a clogged up hand me down headache. You could travel and buy/install a used one from out of state, and I bet there are shops in Reno/Draino doing such business.

    The last time I went for a smog/emissions test the tech looked under the car for the cat (using a telescoping mirror), I asked him if he had ever seen an aftermarket cat on a Prius before and he said no. I then asked if aftermarket C.A.R.B. cats were available for the prius as the OEM costs so much and he said yes, then I corrected him :confused:

    If needed, I am local and have a mini-vci cable you can borrow for code reading.

    Some reading material that you might find of interest :

    Catalytic Converter Clogged - Glazed Over | PriusChat

    2006 Prius 140k miles: Rebuilt battery replaced 4 times in 1 year - decision to keep or trade? | PriusChat

    Oh, and how many miles again?
     
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  14. Colton1er

    Colton1er New Member

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    Update - I acquired an OEM cat today and installed it...disconnected the 12v battery and let it sit for a while. Then hopped in and drove about 30 miles with no lights / no issues. Seems to be back to normal..hopefully.

    @ everyone freaking out about my oil comment. Allow me to re-phrase - I don’t change the oil personally on this car, because I don’t have ramps in my garage to get underneath it. I do check the oil to make sure it has enough and is the right color. If it was burning an exorbitant amount of oil I’d know. Although I did notice that my o2 sensor is looking pretty white while replacing the cat, I’ll probably be replacing that soon.

    SFO - thanks for your response! I have about 155k on my car now. Good to know there’s some locals here. P0420 was the only code I was getting. Thanks for the reading material!
     
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  15. Mavi

    Mavi Active Member

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    Dang just 5k over the legal warranty limit. But it seems you've taken care of the issue, so congrats irregardless ;)
     
  16. audiodave

    audiodave Active Member

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    How did the old cat look down the pipe? Hopefully code doesn't come back.

    Posted via the PriusChat mobile app.
     
  17. Colton1er

    Colton1er New Member

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    It looked pretty bad, definitely way worse off than the replacement.

    Unfortunately I just got in the car and the lights are back on. Probably going to take it somewhere to get a proper diagnosis. Might try replacing downstream o2 sensor first.
     
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  18. Raytheeagle

    Raytheeagle Senior Member

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    There are some good local shops around the bay area :).

    You can try Arts Automotive in Berkeley or Luscious Garage in SF. They are hybrid shops;).

    Do you have a code reader and is it still the cat code that is being displayed?

    Good luck and keep us posted (y).
     
  19. exstudent

    exstudent Senior Member

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    10years/150K miles.

    OP is over by 2years (2018-2006) and 5K miles (155k - 150K). Out of warranty by both measures. OP could have tried for Goodwill Assistance. But unlikely since has not been patronizing anToyota dealer for paid service.
     
  20. Colton1er

    Colton1er New Member

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    Thanks! I just went and got a Denso o2 sensor from Auto Zone and I’m going to replace that before I take it anywhere, because I noticed the current one was a little fried while I was changing out the CAT.

    To be completely honest, I’m a little scared to drive the car anywhere in it’s current state (with all the lights on) though it does seem as though it’s running normally after installing the new CAT, so hopefully the o2 sensor does the trick on at least a few of them.

    If this doesn’t work, I might just try and get it towed to Luscious :(
     
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