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Can't start car normally

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Mangix, Apr 17, 2022.

  1. Mangix

    Mangix Junior Member

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    Only way I can start it is by jumper cables. The battery seems to be fine. Although I noticed something interesting. Pictures attached.

    Anyone have any idea?
     

    Attached Files:

  2. mr_guy_mann

    mr_guy_mann Senior Member

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    You appear to have damage to the connector -that black box is a "back up" power supply for the braking system. As far as not being able to start the car, what is the voltage at the battery terminals and at the underhood jump start point?

    Posted via the PriusChat mobile app.
     
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  3. Mangix

    Mangix Junior Member

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    do I just measure that with a multimeter?
     
  4. mr_guy_mann

    mr_guy_mann Senior Member

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    Yes. Turn your multimeter onto whatever range or setting to measure up to 20 volts DC. Red probe on the battery (+) (the terminal closest to the front of the car), black probe on the (-) battery terminal closer to the rear. Write down the result. Repeat, red on battery (+), but then put the black on the bolt that holds the (-) cable to the body.

    Open the hood and the fuse box on the left (driver's) side. Put the red probe on the metal tab under the little red flip up cover (jump start point), black on something- (clean - not painted) metal on the body- I usually go to a stud/nut for the left upper strut mount just above and behind the fuse block. Write that down and report back.

    Ideally you would take at least one of the measurements while someone is pressing on the power button.

    Posted via the PriusChat mobile app.
     
    #4 mr_guy_mann, Apr 19, 2022
    Last edited: Apr 19, 2022
  5. Mangix

    Mangix Junior Member

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    Alright just got to it.

    Setting my multimeter to 2V results in 1.632 volts at the battery. At the front it's interesting. It fluctuates between 0 and 1.6. Maybe I can't get a good connection with my multimeter.
     
  6. bisco

    bisco cookie crumbler

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    nah, you just need a new battery. what makes you think it's good?
     
  7. cyberpriusII

    cyberpriusII Prodigyplace says I'm Super Kris

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    Uh, I am no expert, but UART trained me on how to use my multimeter here on PriusChat several years ago and setting the meter to 2v is not going to work.

    Set it to 20v -- or read through this link.

    How to Use a Multimeter - learn.sparkfun.com
     
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  8. bisco

    bisco cookie crumbler

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    maybe it's a 1.6v battery
     
  9. cyberpriusII

    cyberpriusII Prodigyplace says I'm Super Kris

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    That would explain a lot. :rolleyes:
     
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  10. mr_guy_mann

    mr_guy_mann Senior Member

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    Something isn't right, as a fully charged (Absorbed Glass Matt or AGM) battery in a Prius should read about 12.8V.

    Check some alkaline batteries (a 9V?)and see if your meter reads correctly. If so and you have good contact with your meter probes then your 12V battery is (probably) toast.

    Might want to jump start the car and read the voltage at the battery connections again. The car's inverter - DC/DC converter supplies about 14V to run the low voltage stuff (lights, heater, controls, etc) AND to charge the 12V battery. If there's a bad connection somewhere then the 12V might never get charged by the car.

    Posted via the PriusChat mobile app.
     
  11. Mangix

    Mangix Junior Member

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    I guess it's a bad battery then. This is what happens when I cheap out...
     
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  12. bisco

    bisco cookie crumbler

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    is it under warranty?
     
  13. Mangix

    Mangix Junior Member

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    I doubt it. It's fairly old at this point.
     
  14. Mangix

    Mangix Junior Member

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    All's well that ends well turns out.

    The battery was purchased on 5/04/2019, with a 3 year warranty. Instead of buying a new one, O'Reilly hooked me up with a new one. Car starts now.
     
  15. Another

    Another Senior Member

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    You’re lucky. I once had a flat tire with a two year road hazard warranty. The tire failed on the last day of the warranty and I didn’t realize the date. Luckily I went into the dealer on that day late in the afternoon on a Saturday instead of waiting until Monday.
     
  16. TMR-JWAP

    TMR-JWAP Senior Member

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    Happy to hear you have a new battery.

    DO NOT forget about the brake power supply. It needs to be repaired. It also maybe why your battery is draining. Replacement boxes can be had at most salvage yards for 10-15 dollars. Get the plug also. Cut the wire harness far enough back that you can splice into yours if needed to repair the damage.