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Need help, reversed polarity installing new aux battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by DMAndy, Aug 28, 2020.

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  1. DMAndy

    DMAndy Junior Member

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    Good People of Priuschat,

    I need help.

    I have hooked up a new aux battery the wrong way around. The front lights came on, along with all turn signals. Corrected the polarity, and the car refused to pretty much do anything.

    After reading the forums, I found and changed a couple of blown fuses in the engine compartment and I connected the 120A fuse in the fusible link that was also blown. The break lights and the passenger compartment lights started working and the start button would turn green when pressed once without the break. With the break, it would turn orange, pressed twice also orange.

    Using Techstream, I tried to get error codes, but no data would come out of the OBDII connector, it did have power. Suspecting a blown ECU, I took out the main engine control ECU, now the car will not respond to the start button (have not put the ECU back yet).

    I have visually inspected the ECU after taking it apart, it seems fine.

    From the beginning of the ordeal, the only lights that would come on on the dashboard are the doors open light, and the yellow check engine light when I would either press the start button with the break pedal pressed or pressed the start button twice.

    And ideas would be highly appreciated.

    Thank you,

    Andy
     
    #1 DMAndy, Aug 28, 2020
  2. edthefox5

    edthefox5 Senior Member

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    You blew the inverter.

    You hooked the 12 up hot. You should have disconnected the 2 leads from the positive terminal assy they just unclick and pull out.

    The fat black wire and thin black wire.

    It was very exciting to try to bolt the negative cable in wasn't it?
     
    #2 edthefox5, Aug 29, 2020
  3. DMAndy

    DMAndy Junior Member

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    Thanks, I'll know better for next time.

    How do I double check that it's the inverter?

    Wouldn't the OBDII port still work with a blown inverter?
     
    #3 DMAndy, Aug 29, 2020
  4. ChapmanF

    ChapmanF Senior Member

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    It is quite possible you have blown some fuses. They don't always blow faster than the expensive electronics, but it is nice when they do. You'll just have to find out.

    If you put back whatever pieces you have taken out, and reconnect the battery (the right way) and start taking voltages at different places, you may find that you have 12 volts at some places and not others.

    If you refer to the "power source" pages in the wiring diagram (more info), you will see that some of the fuse links are located so they will kind of partition the electrical system leaving some parts with power and some without. From your measurements and the diagram you will often be able to deduce where that happened.
     
    #4 ChapmanF, Aug 29, 2020
  5. DMAndy

    DMAndy Junior Member

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    I think I have checked all of the fuses that I could, but I will definitely take a look of the power source pages to see if I can check more. It certainly sounds easier than replacing expensive parts. Thank you.
     
    #5 DMAndy, Aug 29, 2020
  6. edthefox5

    edthefox5 Senior Member

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    If the car wont go into Ready the inverter is not turning on. How did you "connect" the 120 amp fuse?

    With a real good reverse jump it usually damages the inverter seen many many of those. The way you did it was a full power reverse input.
    Ouch. How did you figure that out the negative lead exploded when you went to bolt it in? Your lucky the battery didn't explode alot of energy there.

    Do you have both leads plugged into the top battery assy theirs a fat black and thin black wire? Fat black is main B+ line to the front fuse box jump point bolt. The thin wire is the inverter sensing wire.
     
    #6 edthefox5, Aug 29, 2020
  7. DMAndy

    DMAndy Junior Member

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    I went and bought a flat 120amp fuse made for a VW I believe, and stuck it in temporarily.

    Nothing remotely exploded. The headlights and the turn signals came on. I didn't even have the key in the slot. I did not try to start the car with the battery hooked up wrong.

    I do have both leads plugged in, yes.

    Is there any way of making sure it is the inverter that is blown, without actually replacing it?
     
    #7 DMAndy, Aug 29, 2020
  8. ChapmanF

    ChapmanF Senior Member

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    Fuses won't always turn out to be the whole story. Figuring out what the whole story is will likely start with you, and a multimeter, visiting various parts of the electrical system to see where you have power and where you don't, and the fuse situation is one thing you'll be able to check with the evidence you're gathering anyway.
     
    #8 ChapmanF, Aug 29, 2020
  9. edthefox5

    edthefox5 Senior Member

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    Go here. Get your printer ready to print like crazy. This gives you access to the full toyota manual this is what the dealer tech would use
    to trouble shoot your car.

    There is a breaker in the inverter. Don't know much about it never seen any posts about it really but I know it has one.
    Buy the minimum 2 day subscription and I hope you are good with a dvm.

    Good Luck:

    https://techinfo.toyota.com/techInfoPortal/appmanager/t3/ti?_nfpb=true&_pageLabel=ti_home_page&contextType=external&username=string&challenge_url=https://techinfo.toyota.com/techInfoPortal/login/techinfo&password=secure_string&request_id=-366903132361169697&authn_try_count=0&locale=en_US&resource_url=https%3A%2F%2Ftechinfo.toyota.com%2F
     
    #9 edthefox5, Aug 29, 2020
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  10. DMAndy

    DMAndy Junior Member

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    Thanks. I have all these. I am decent with computers, just not very good at fixing cars.

    Techstream doesn't work as the OBDII port doesn't work.
     
    #10 DMAndy, Aug 29, 2020
  11. edthefox5

    edthefox5 Senior Member

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    #11 edthefox5, Aug 29, 2020
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  12. DMAndy

    DMAndy Junior Member

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    Sounds like I'll have loads of fun. If it was any other car, I'd just buy another one. But it's a Prius, my Prius.
     
    #12 DMAndy, Aug 29, 2020
    offib, bisco and SFO like this.
  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    My first idea is that you should remove the cover of the main relay/fuse box next to the inverter. Within that box is a 5" long clear/white plastic box that contains the fusible links assembly. One of those links is the 100A DC/DC converter fusible link. Inspect the links and if you see one has blown, you need to replace that entire clear/white plastic box. That is not very easy to do as the relay/fuse box has to be removed for access.

    My second idea is that you should inspect the fuses in the fuse box located under the instrument panel, driver's side.

    My third idea is that you should reinstall the engine ECU.
     
    #13 Patrick Wong, Aug 30, 2020
  14. edthefox5

    edthefox5 Senior Member

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    hey pat good to see you...

    I think he already replaced that in post #7 but it sounds pretty shady a VW fuse.. ...

    DMandy Please post a picture of that install of that VW fuse..
     
    #14 edthefox5, Aug 30, 2020
  15. DMAndy

    DMAndy Junior Member

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    Thanks for the ideas. The first one I did at the very beginning, I just accidentally put 120A fuse instead of 100A fuse in my initial post. The connection is very temporary, but it does the job, it lets electricity through now (shout out to Edthefox).

    Number two is a great idea again, unfortunately, I have already inspected them. What I do plan to do is to see which of those fuses actually gets current, not as in whether they let current through, but whether current reaches that point in the car.

    Number three: yes, I plan to do that today, since it doesn't seem blown. That said, I have already bought another one, so if it does turn out to be the ECU, it will be relatively quick and easy to replace.

    Any idea why the OBDII port wouldn't transmit data but still get electricity?
     
    #15 DMAndy, Aug 31, 2020
  16. DMAndy

    DMAndy Junior Member

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    Hi Ed,

    I do appreciate you hanging in there with me. As above, the link at the 100A fuse is very temporary, but it does the job (source: my multimeter told me so), the break lights started working since that fix.

    In one of your earlier posts you mentioned a troubleshooting tree in one of the Toyota documents. Would you be able to point me to the exact section? Thanks.
     
    #16 DMAndy, Aug 31, 2020
  17. DMAndy

    DMAndy Junior Member

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    Thanks for the suggestion ChapmanF, the plan for today is looking at the power sources flow chart and planning what to check and where.

    I have read somewhere that relays can get stuck after a reverse polarity event, so will try to check those too.
     
    #17 DMAndy, Aug 31, 2020
  18. edthefox5

    edthefox5 Senior Member

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    Relays don't get stuck.
     
    #18 edthefox5, Aug 31, 2020
  19. jerrymildred

    jerrymildred Senior Member

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    Just to clarify respectfully:

    I've replaced stuck electro-mechanical relays as an industrial electrician a couple times. It's very rare, but they can stick closed. The ones that stuck for me had had millions and millions of operations, though. Take out the relay and bang it on something and it will usually release and work long enough to get a replacement. Not saying this is the problem, of course, but the blanket statement that relays don't get stuck isn't always accurate.
     
    #19 jerrymildred, Aug 31, 2020
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  20. edthefox5

    edthefox5 Senior Member

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    I agree it happens but very very rare in a car. Never seen one in a car have you?

    what I should have said was:

    "I don't think that's your problem".
     
    #20 edthefox5, Aug 31, 2020
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