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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.

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  1. Andrew Nakas

    Andrew Nakas New Member

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    2009 Prius
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    N/A
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    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.
     
    #1 Andrew Nakas, Jul 16, 2024
  2. Tombukt2

    Tombukt2 Senior Member

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    Is the b r a k e in red on on the left of the display when the car's on running whatever? There has to be some codes you got an airbag light on so that tells me the code readers that you're using don't communicate well or play that nicely with all the computers in the system body modules and all that so you need a more capable scanner there's a pile of them If the car is driving and moving well you should be able to run by anybody you know with the capable scanner which may be lots of people if you have car nut friends they don't need to necessarily have the Toyota software loaded up for the given scanner they're not trying to do anything but read the codes not perform any maintenance functions at this point once you have the real codes then you can begin to make the necessary real repairs if your battery's charging like you see 13.85 when the car is ready and everything seems to be driving normal at this point I would be looking for some funny or different things from the break Do you see the regeneration what is it purple lines happening when you let off the gas or step on the brake? Usually when I start seeing a lot of orange lights! With the two have circles ABS VSC b r a k e light in red lit up generally work getting to break or wheel issues
     
    #2 Tombukt2, Jul 17, 2024
  3. TMR-JWAP

    TMR-JWAP Senior Member

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    First question that comes to mind is ...what problem are you experiencing that you're trying to solve? Is it just warning lights, but the car is driving normally?

    The positive terminal on your 12v battery has a fuse assembly on it. One is a large, bolted in place fuse and one is a small 5A(?) normal style automobile fuse, which is voltage feedback sensing for the inverter to keep the battery charged, etc. Pretty sure the big fuse is ok since the car powers up, but what about the small fuse? Perhaps it got smoked on the reverse jump.
     
    #3 TMR-JWAP, Jul 17, 2024
    Brian1954 and Tombukt2 like this.
  4. ChapmanF

    ChapmanF Senior Member

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    ^ This, if you haven't checked that yet.

    As for getting the codes, we have a thread comparing scan tools and identifying those that can read all the codes:

    Gen2 OBD2 app review | PriusChat
     
    #4 ChapmanF, Jul 17, 2024
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  5. Andrew Nakas

    Andrew Nakas New Member

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    Vehicle:
    2009 Prius
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    N/A
    Hey it did get smoked on the reverse jump and I actually put a spare fuse in but I think i didn’t insert it correctly and once I a new one in the errors went away! Thanks for all the help. I ran the error codes before I fixed it and I was getting 90a08 and 90a09 but now I get no error codes.

    Thanks for all the help everyone.
     
    #5 Andrew Nakas, Jul 25, 2024
    Brian1954 likes this.
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