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P0401 - EGR Code, 2010 Prius, Need Help

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Shamrock2012, Jul 17, 2019.

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  1. Shamrock2012

    Shamrock2012 New Member

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    Hey guys, I have been having issues with a P0401 code on my 2010 Prius with 197,000 miles

    I asked my mechanic to try cleaning the Egr system/valve(unsure of exactly what parts he cleaned out)

    The code goes off for a time, usually running Shell gas. Then comes back up. I noticed the valve was on recall but my vehicle is past the 150k mi Warranty.

    The car does not seem to be burning oil and otherwise seems to be running fine.

    Any advice? Do I need to replace both the valve and cooler? What part replacements do you recommend?

    Thanks!
     
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  2. Raytheeagle

    Raytheeagle Senior Member

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    The whole egr circuit needs to be cleaned stem to stern;).

    If you’re not sure what the mechanic cleaned, ask him and if he can’t remember, probably best to tackle the whole circuit:cool:.

    Other things to do:
    • Keep an eye on the engine coolant level as you might be at the tip of the head gasket iceberg
    • Install an oil catch can to catch the PCV vapors
    Good luck and keep us posted (y).
     
  3. GrGramps

    GrGramps Active Member

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    "the tip of the head gasket iceberg"

    Impending doom - unless you don't believe in global warming!
     
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  4. JC91006

    JC91006 Senior Member

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    The valve is relatively inexpensive part to replace, I would clean the EGR circuit and replace the valve
     
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  5. Mendel Leisk

    Mendel Leisk Senior Member

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    EGR valve? It's over $200.

    EGR System for 2010 Toyota Prius | McGeorge Toyota Parts

    Very likely he did not completely clean the EGR circuit: it involves everything from the connection to the exhaust manifold to the intake ports. You need to remove the wipers, motor/linkage cowl, intake air snorkel and filter box , throttle body, intake manifold (and thoroughly clean it: it has egr passages), and (obviously) the EGR tube, valve and pipe (see link).

    Some boilerplate:

    The simplest way to see where you're at, is to check the degree of carbon build up in the EGR tube, a stainless steel connecting pipe between the EGR valve and intake manifold. Watch @NutzAboutBolts video #16 here:

    Nutz About Bolts Prius Maintenance Videos | PriusChat

    Two or three other videos linked there too, for the full cleaning of the intake manifold, full EGR clean, and Oil Catch Can install.

    Good thread:

    EGR & Intake Manifold Clean Results | PriusChat

    Another:

    Oil Catch Can, Eliminate that knock! | PriusChat

    Somewhat tools worth having:

    E8 Torx socket (mandatory)
    E6 Torx socket (optional, but good to have, to remove the throttle body studs from intake manifold)
    3/8" ratchet wrench, regular and long handle, flex head, you can never have enough
    1/4" ratchet wrench, or 3/8" to 1/4" reducer
    Ratchet extensions: you can never have enough
    Long needle nose piers, straight and bent tip
    Ratcheting 12mm box wrench (optional, but makes disconnection of the EGR cooler from exhaust easier)
    Torque wrench (3/8" and 1/4" both good to have)
    Floor jack and safety stands (or ramps): basically some method to raise front, if you need to take underpanel off, which you may need to, both for access and to recover dropped items.

    Repair Manual info attached:
     
  6. JC91006

    JC91006 Senior Member

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    It's probably close to $200. I should say relatively cheap compared to other repairs on this Turd Gen
     
  7. Raytheeagle

    Raytheeagle Senior Member

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    Salvage yard was 1/4 of the OEM list;).

    Help keep useable parts functioning and out of the recycle stream(y).
     
  8. Shamrock2012

    Shamrock2012 New Member

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    So I don’t need to buy a new egr valve/cooler and have that installed?
     
  9. Ed Beaty

    Ed Beaty Active Member

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    I got a very nice one (barely even had to clean it) off eBay for USD140.00 shipped.
     
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  10. Raytheeagle

    Raytheeagle Senior Member

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    4 years ago I bought a salvage yard cooler and valve for $100:).

    Slight cleaning required ;).

    But they work just as well as new(y).
     
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  11. Mendel Leisk

    Mendel Leisk Senior Member

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    To buy new and pay a mechanic is extremely costly.

    The components in your car are hopefully viable once cleaned, and if at all possible I would DIY the cleaning. You really need to clean everything between the exhaust manifold connection and the engine intake ports; that involves the intake manifold as well. Doing it yourself, and just cleaning what you have, you get through this with next to zero expense.

    Have a look at the @NutzAboutBolts video links I mentioned above, both the EGR and Intake Manifold cleaning. And for sure read through the linked threads. Lots of info in there.
     
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