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Someone has done it again! Reverse polarity jump 2016 Prius

Discussion in 'Gen 4 Prius Main Forum' started by Geoff Hejde, Dec 5, 2023.

  1. Geoff Hejde

    Geoff Hejde New Member

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    I admit it, it was me....I want to soften the blow in my mind that I would do something like this so I will qualify it by saying it was dark. Yes I could have taken the time to get a light but I didn't. The spark and then the horn sounding off was the the clue I needed but the damage was done. The car would not recognize my key and after playing around of course I was able to start the motor but all the dash warning lights were flashing and warnings were coming up about oil pressure and the like so...
    I spent a minute under the hood and found the fusible link had one of the fuses blown so I crossed my fingers, ordered a new one and installed it. The key is still not recognized but the motor did start up and the doors unlocked, I was also able to put the car in gear and move forwards and back. Most is not all of the dummy lights were on and I got various warnings about the engine not performing properly so I shut it down fairly quickly and decided to do some research.
    The best I have found so far is some pretty detailed information on this site about the same issue on a Gen 3 Prius. I usually work about 10days in a row and then have 4 or 5 off and I am just back to work now for another 10 day stent. I figure at the least there are some other fuses and/or relays that have blown. Of course I am hoping for that and not the heart of the beast. Can anyone shed some light on the Gen 4, mine is a 2016 and has a lot of miles on it but I really am not ready to retire it. How could anyone do such a thing is what I might say if it was not me who did it. I humbly ask for information from anyone that might be able to help me. Thank you!
     
    bisco and parked like this.
  2. bisco

    bisco cookie crumbler

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    best you can do is get a prius aware scanner, read the codes and follow the sevice manual trouble shooting.
    salvage parts will keep the cost down. this is not usually and end of life issue
     
  3. Drakxyfly

    Drakxyfly Junior Member

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    The car needs to go to an experienced electrical technician. It's impossible to tell what you fried. Most likely the ECU is fried. A scan tool may not even work on the vehicle at this point.
     
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  4. sylvaing

    sylvaing Active Member

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    Note to self, use a jumper kit/battery tender that has polarity detection. It might save a lot of headaches.

    However, before that note was taken, I did put an old school battery tender in reverse polarity on my 400cc ATV at the cottage. It stayed like that for a month! When I noticed it (ie, didn't start, duh), I unplugged it, unplugged the battery (battery was showing -5V!), used my boat battery to see if the ATV logic was fried. Nope, ATV was fine, phew. I then on a hunch decided to tender the battery with the correct polarity. Took over a month but the battery went to its nominal voltage and lasted over a year.
     
  5. Drakxyfly

    Drakxyfly Junior Member

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    Huh polarity detection??? It's called paying attention before you put the clamps on. Takes two seconds to look before you connect it. Not only are the posts usually a different color and size, they are labeled with a + and - sign. Match the color of the clamp in your hand to the color on the battery. Really no offense but it sounds like you should just be staying away from electrical systems......
     
    Doug McC likes this.
  6. bisco

    bisco cookie crumbler

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    i think the op did his mia culpa's, now he needs our help
     
  7. Drakxyfly

    Drakxyfly Junior Member

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    Nothing anyone here can do unfortunately, and if the op has a history of swapping polarity, they aren't fixing it themselves either. Car needs a specialist period. Best to stop blaming it on polarity detection or anything like that and take the car to someone that can fix it.
     
  8. Mr.Vanvandenburg

    Mr.Vanvandenburg Active Member

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    If your engine ran after, it isn’t the ignition circuit of course. You may be ok, go with the hope the fuse did it’s job.
    I guess you would have fully charged the battery and now will see if everything relearns itself.
     
  9. sylvaing

    sylvaing Active Member

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    I connected the positive lead to the + and negative lead to the -, but I didn't notice that the cable I used for the tender (it had different cable end, depending on its use) was for a different tender and the red plug ended being negative and the black one positive. Anyway, mistakes happen and that's why most if not all battery tender and booster now have polarity detection to prevent connecting it the wrong way. I old co-worker of mine is now deaf in one ear (happened in the early 90s) because the battery of a car he was boosting exploded from such an error.
     
  10. BiomedO1

    BiomedO1 Senior Member

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    Welcome...
    You being able to start the car is a good sign. Disconnect the negative battery post cable for 15-30 minutes. This should clear most of the codes from the mishap. Fire-up the car and drive it around the block. See what codes come back and start tackling them one at a time.

    Hope this helps...
     
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  11. Drakxyfly

    Drakxyfly Junior Member

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    Well hopefully third times not the charm and you learned to double check all your connections from now on regardless of polarity protection or not. If the car starts and doesn't recognize the key you may have wiped the ECU. That's easy to reprogram..I would see if it drives, many times the warning lights go away after a drive and a couple on off cycles. If not you need a technician.
     
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  12. rjparker

    rjparker Tu Humilde Sirviente

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    Believe it or not but most of the time the ecus are fine. They have protective circuits to shunt reverse polarity and blow fuses.

    Check every fuse and fusible link one by one and carefully reinstall each into the right spots. Several people have screwed this up and have left a fuse holder empty or installed the wrong fuse. Check all fuses and fusible links in the interior and engine compartments. There should be big 60-140a fusible links.

    Then power cycle the 12v battery and try again.



     
    #12 rjparker, Dec 6, 2023
    Last edited: Dec 6, 2023
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  13. Mendel Leisk

    Mendel Leisk Patron saint of newly poured sidewalks

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    At least with the stock Yousa on our ‘10, it was pretty subtle. There’s embossed plus and neg symbols on top of case, no colour difference, near-impossible to make out in poor light. You can improve this with a bit of paint, or market pen.

    Posts are, well, metal colour, with one a wee bit smaller. The main clues might be red cap on the positive post, and from the other post a cable runs a very short distance, to car body.
     
  14. Drakxyfly

    Drakxyfly Junior Member

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    It's still clearly marked in more than one way with both colors and a positive and negative sign. The red and black are universal industry standard. Still it takes like two extra seconds to double check your connections before plugging it in.
     
  15. sylvaing

    sylvaing Active Member

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    Maybe you should check who you're replying to, I'm not OP. Mine was an ATV, not a car :p
     
  16. Drakxyfly

    Drakxyfly Junior Member

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    Silly forum lag I could have sworn I did. I thought it was op and they already fried one atv battery and now had their sights set on killing their Prius too :LOL:. I was like how many times this person have to kill a battery before they learn :ROFLMAO:. But it's def easier to swap polarity with the battery out of whatever vehicle it's in.
     
    Doug McC likes this.
  17. hakan

    hakan Junior Member

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