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Kids got water in spare tire well and now HV battery terminals are badly corroded

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by opivy224, Jun 23, 2020.

  1. opivy224

    opivy224 Junior Member

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    Prius started throwing some low voltage and Hv battery errors, so I opened up the back and discovered a large pool of water in my spare tire area. I’m pretty sure it was from the kids spraying the hose around the Prius when the hatch was open.

    So I went ahead and opened up the battery while it was still in the Prius and discovered heavy corrosion on most of the battery terminals.

    I was thinking about removing all the terminals and harnesses while the battery is still sitting inside the Prius so I can clean them. Is this advisable or should I remove the battery completely?
     

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  2. bisco

    bisco cookie crumbler

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    don't yell at the kids, more likely your getting leaks when it rains. search here for solutions. i can't advise on the connectors, but it might be worth examining the entire battery
     
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  3. AzusaPrius

    AzusaPrius Senior Member

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    Yea that didnt happen because of the kids, that is what happens over a long period of time. Yes you can do all that with it still in the car. Dont forget to remove the orange safety plug first.

    Best if you just order a new set if nickel plated bus bars and nuts.


    Posted via the PriusChat mobile app.
     
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  4. davecook89t

    davecook89t Senior Member

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    What codes were you getting? If none of them specifically point to weak modules, it might be worth a try (leaving the battery in the car and just cleaning the bus bars, bolts and nuts). Just be careful, even the with safety plug removed, it is possible to get a good jolt, if you touch the wrong thing.
     
  5. Albert Barbuto

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    The corrosion does look bad, however underneath the nuts it usually is perfectly clean. This is what matters most.
    I suggest removing two nuts on one of the worst looking bus bars, and see what it looks like underneath. If nice and clean, just brush off the outer corrosion "in car", if desired, on the entire pack. A vacuum cleaner and stiff brush will make this job fast and easy.
     
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  6. TMR-JWAP

    TMR-JWAP Senior Member

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    Considering the amount of disassembly you've already performed, my opinion would be to remove the battery for the additional work. This way you can have it on a work table at a reasonable height for ease of work and viewing, along with reassembly. Not to mention, you won't be surrounded 360 degrees by metal while working on a component with significant electrical energy stored inside.

    Safety first, my friend.

    And if you are interested in really doing a good job? Just purchase a new wire frame #2 from Toyota to replace the wire harness/busbar assembly on the side of the battery which faces the seats. Trying to clean/reuse this harness can lead to many problems if you put a crack in one of the sensor leads. They are very susceptible to damage due to the corrosion you'll see on the wires and crimp area. The busbars shown in your photo (from the side of the battery facing the rear of the car) are easy to clean and reuse.

    Torque all busbar fasteners to 48 INCH pounds (4 ft-pounds)

    And..you may want to look at the bottom of the cubby hole where the 12v battery is located. Odds are very good you'll have a few inches of water in there also. Each of these areas has a rubber plug. I've removed the plugs (or drilled 1/8" holes) in those locations in my cars just so the water won't build up.
     
    #6 TMR-JWAP, Jun 23, 2020
    Last edited: Jun 23, 2020
  7. George W

    George W Active Member

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  8. opivy224

    opivy224 Junior Member

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    Okay, you guys are right, I do see some rust around the inside of the hatch seal. The kids were spraying the hose around my car when the hatch was open, so I just assumed that was it. I wouldn't have been upset with them anyway, they don't know any better.

    So I took all the battery terminal harnesses off last night and discovered one of the plugs is nuked. Luckily I ordered the whole assembly on eBay the other day. I just hope the computer or whatever this was plugged into is still good.
     

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  9. opivy224

    opivy224 Junior Member

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    The male end of the port on this metal box that it plugs into looks fine
     

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  10. opivy224

    opivy224 Junior Member

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    And yes indeed, my 12v battery well was filled with water. I did notice my car seemed unusually humid sometimes, I guess that explains it. I still cant pinpoint where it is leaking, I will have to go through some of the previous threads on the subject.
     
  11. TMR-JWAP

    TMR-JWAP Senior Member

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    The socket you have in the photo does not match the plug in the previous photo. That 'nuked' plug and the socket it came out of are no good ===> The ecu is NFG and will need to be replaced. This is a VERY common occurrence on the Gen 2 cars. The harness/plug is called 'wire frame #2' and is available brand new from Toyota for <$60.
     
  12. opivy224

    opivy224 Junior Member

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    Thanks, you were right. The socket was below and it's fried too. I just ordered a new ECU. The harness should be here soon as well. Thanks for all the help gents!