Missing this wire. Is it important?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by ILuvNAB, Sep 3, 2021.

  1. ILuvNAB

    ILuvNAB New Member

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    Bought my Prius used a few months ago. I never bothered to remove the engine cover until today and I noticed my car does not have this grounding wire. Only an empty thred hole on the valve cover. I looked down to see if bolt simply got loose and wire got disconnected, but I don't even see any loose wire near that region.
    How important and how bad is it?

    Thank you
     

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  2. StarCaller

    StarCaller Senior Member

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    mine doesn't have one neither, so if Toyota didn't put it in from the factory it can't be sooo important /
     
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  3. ChapmanF

    ChapmanF Senior Member

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    That's not even shown in my wiring diagram. I can see you have the two ground points next to each other on the front of the valve cover. Those are in the diagram.
     
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  4. xliderider

    xliderider Senior Member

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    I have one of those ground wires. You can easily make one out of 10 gauge wire and some spade terminals.

    Posted via the PriusChat mobile app.
     
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  5. ChapmanF

    ChapmanF Senior Member

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    Where is the other end connected? (I would look in the wiring diagram, but can find no such wire there.)
     
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  6. audiodave

    audiodave Active Member

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    Just connected to the body.
    Posted via the PriusChat mobile app.
     
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  7. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Some back story, in a car with a engine belt driven alternator, good grounding of the engine is crucial. The same basic engine block is used in such cars, so Toyota includes the connection point in a Prius even though it has no engine belt driven accessories at all. 12 volt power is provided by a DC to DC converter in the Inverter assembly. I bet the Inverter has ground straps, like most cars have them for the engine.
     
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  8. ChapmanF

    ChapmanF Senior Member

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    The inverter/converter brackets are bolted directly to the body. Engines generally have rubber mounts allowing them to move and shake, and need ground straps to conduct around those.

    The Prius engine still needs good grounding; there are electrical devices on it. On Gen 3 you will see two big ground connections right next to each other on the front of the valve cover. Those are the ones the Gen 3 wiring diagram shows in the engine compartment ground points diagram.

    Weirdly, while I don't find this other wire in the wiring diagram, I do find it in the parts catalog. About $20 if you want the official one. It has a whole diagram all to itself.

    [​IMG]
     
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  9. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Our 2010 has it. You can just see other end, bolted to body, peeking through between coolant hose and AC line, near corner of coolant expansion tank.

    5EF6EF5B-6FB4-407B-8AB1-A31E1CD1A227.jpeg
     
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