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Air fuel ratio - carbon deposits - ? work required?

Discussion in 'Gen 3 Prius Main Forum' started by Pablo57, Jul 20, 2021.

  1. Pablo57

    Pablo57 New Member

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    Hello,

    2015 Toyota Prius, 191,000 miles. I had a check engine light come on, took it to dealer. They said tech found a code for the air fuel ratio to have an imbalance and is recommending the intake manifold and
    gasket be replaced due to
    heavy carbon deposit. Does this sound right or wrong, and why?

    Pablo57
     
  2. PriusCamper

    PriusCamper Senior Member

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    Lol, that's why we call them stealerships... So wasteful is their standard operating procedure of replacing as many expensive parts as possible with brand new. But it just needs to be cleaned and evidently they don't know how! Lol...

    But take it to real mechanic instead and they'll recommend a simple induction cleaning of the throttle body, intake manifold and mass air flow sensor.

    Alternatively, if you want to DIY you could find some youtube videos that will show you how... OR if you want to be extra cautious buy a used intake manifold from a wrecker for 10% of what Toyota charges for new and then take your time cleaning it and swap it with the one you have, which is a fairly simple procedure.
     
    Mendel Leisk likes this.
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    Very easy to DIY the intake cleaning. Attachment shows intake manifold info. It’s NOT necessary to disconnect throttle body coolant lines for this.

    the elephant in the room though: had Exhaust Gas Recirculation circuit ever been cleaned? More info in my sig, the bad flywheel link.
     
  4. mr_guy_mann

    mr_guy_mann Senior Member

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    Maybe. If the code is something like P219A, it means that the air/fuel mixture for one of the cylinders is different than the other 3. It can really be almost anything- partial intake or EGR passage restrictions, valvetrain problems, restricted fuel injector (a common cause), exhaust leak at the cylinder head, etc.

    Posted via the PriusChat mobile app.