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Gen3 Intake Manifold Cleaning results in Check Engine and then Hybrid System Message

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Doug Pinkerton, Aug 24, 2024.

  1. Doug Pinkerton

    Doug Pinkerton Junior Member

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    So, I've read numerous threads here about issues after cleaning the intake manifold. They all seem to mention engine that either won't run or runs very poorly and most posters then found a hose they forgot to connect.

    In my case, the engine started great and seemed to run fine but then the Check Engine Light came on and into a test ride I got the dreaded "Check Hybrid System Stop the Vehicle in a Safe place."

    Posting here on the off chance that someone sees this and has a thought. Tomorrow AM I plan to check my connections, but my hunch is that, if it were a hose, the engine wouldn't run and sound fine.

    Let me know if you have a thought.

    Thanks!
     
  2. Tombukt2

    Tombukt2 Senior Member

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    Now ya read codes/s . How dirty was everything when you clean the intake did you bother cleaning the EGR cooler and it's piping? Sounds like you're doing this without a scan tool so maybe you did the cleaning and something else is wrong I don't know usually if you can read your code you'll get a pretty simplistic answer to deal with generally. Maybe a bad plug or a bad coil pretty simple and straightforward.
     
    Brian1954 likes this.
  3. ASRDogman

    ASRDogman Senior Member

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    If you forget to attach the PCV hose, that is what you will get. Because too much air
    is being sucked into the cylinders and the engine won't start. What you are likely hearing
    is the engine turning over, but not starting.
    Remove engine air filter housing and check it. It's right behind the top smaller connecting is for
    the cooling lines. The pcv hose is about the size of a nickel.
    But you should check all the vacuum lines. It's easy to miss connecting them.

     
  4. Brian1954

    Brian1954 Senior Member

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    Like Tom mentioned, you need to read the trouble codes with an OBD2 scan tool. Once you have the trouble codes, then you can determine a plan to fix the problem.
     
  5. Doug Pinkerton

    Doug Pinkerton Junior Member

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    First, thank you all for taking the time to respond.

    All good now.
    I was convinced the connector going to the inverter cooling pump wasn't something I hadn't disconnected and was for an accessory.
    While I feel completely stupid, I am at least happy now!
     
    Brian1954 and Mendel Leisk like this.
  6. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Disconnected PCV hose at intake will shut the car down, fast, and give check engine light. How about:

    The vapour hose from gas tank, connects just below throttle body, at 6 o'clock (as you stand at front).

    You've got the MAP sensor plug connected (similar, around 3 o'clock).

    Throttle body connector?

    MAF sensor plug (around back of air intake, just downstream of air filter).

    There's a few more, but those are relatively easy to miss.
     
  7. ASRDogman

    ASRDogman Senior Member

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    Glad all is working now!
    And don't feel bad, it happens to everyone.
    I forgot to connect the pcv hose to the manifold Friday.
    I had to take the air filter box out to find it. It runs very smooth now!

    I've cleaned the egr system 4 or 5 times now.....

     
    Doug Pinkerton likes this.