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Reversed polarity, replaced fuses, but warning persists.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Andrew Nakas, Jul 16, 2024 at 7:39 PM.

  1. Andrew Nakas

    Andrew Nakas New Member

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    Location:
    Bozeman Montana
    Vehicle:
    2009 Prius
    Model:
    N/A
    IMG_9594.png IMG_9593.jpeg
    Hello,
    At the beginning of this month my 09 Prius that I just got used in May battery died about an hour and a half outside of town.

    We tried to jump it from the front and that didn’t work. In hindsight I should have checked to see if the donor truck had polarity reversed or not. I called triple a and the mechanic couldn't jump it from the front either and tried from the battery in the back, but first “tested the jumper cables” by clicking them together when they were attached to my battery in the rear. A little while after he noticed the 100 amp fusible link fuse was blown and we towed the Prius to the dealer.

    After opting not to pay 600 dollars to replace the fusible link from the dealer I replaced it myself. And then checked the other fuses and replaced the throttle fuse the dome fuse which were confirmed blown and a couple others just for good measure. I also replaced the battery with a new oem one. At this point the car worked pretty much the same as before the incident except the charging system warning light, hybrid system warning light, red triangle of death, vsc light, and brake (!) light are all on. In addition I think these are more symptoms of the system codes but the passenger airbag is stuck on and cruise control does not work.

    The odb2 reports back no codes, however one was a bad Walmart code reader and the other a loaner from napa auto parts so I’m not sure if these were able to read any hybrid specific codes or not? The Napa one had three sections to read code but no codes.

    I tested all the fuses under the steering wheel, and in the big engine fuse box and outside of the two or three that were confirmed bad they all seemed to be working fine.

    The battery tests as 13.85 volts when the car is running and 12.9 when it’s off. I felt the inverter pump motor and it seems to be running and the hybrid battery does charge when the car is on, and I’ve driven it about 30 miles and it feels pretty normal. I checked the 120 amp fuse on the back by the battery and that looks fine too.

    I’ve read a lot of the reversed polarity threads from here but am kind of lost outside of next steps to do besides buying a used inverter or paying the dealership to diagnose it and maybe tell me I need a new inverter or something else.

    Any ideas for what I should do next to diagnose and fix this issue? Thanks for the help! These threads and info have gotten me this far and I’m getting close to the final boss whatever that ends up being.