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Gen 2 Prius Died and won't start with a full battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Cypress650, Aug 30, 2024 at 6:43 PM.

  1. Cypress650

    Cypress650 New Member

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    Hello, recently I was surprised to find my Prius, which I had driven without issue just hours earlier, to be completely dead. The battery was brand new, maybe weeks old and it gave me an astounding 3.6v reading!
    Using a smart battery charger I charged it up to 12.8 volts. That got most electrical systems back on. The fob works, lights turn on, but pressing the ignition does nothing, no lights, nada. I realized after the fact that my gas was low and that could be an issue (I still had one bar, wasn't flashing) so I added about 8 gallons, still nothing.

    I tried various things like attempting to start then disconnecting the white plugs from the positive battery connection and letting it sit, that seemed to work but not for me.

    The fusible link seems to still be intact. Not sure what else to do or try.
     
    #1 Cypress650, Aug 30, 2024 at 6:43 PM
  2. Tombukt2

    Tombukt2 Senior Member

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    So when you push the start button with the brake pedal depressed you're not hearing the clicking of the relays in the back of the car that you've been hearing as long as you've owned the car?
     
    #2 Tombukt2, Aug 30, 2024 at 10:16 PM
  3. mr_guy_mann

    mr_guy_mann Senior Member

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    Does the dash (speedometer) and the warning lights come on with the power button?

    Or does the power button "do nothing"? If so, then check the AM2 fuse in the underhood fusebox. That fuse will pop if the inverter coolant pump fails in a "short circuit" mode.

    Another possibility is that a capacitor on the Combination Meter (speedometer) circuit board has failed which prevents the CM from turning on (& can affect the normal "power on" sequence).

    Posted via the PriusChat mobile app.
     
    #3 mr_guy_mann, Aug 30, 2024 at 11:28 PM
  4. Cypress650

    Cypress650 New Member

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    Correct, no clicking reactions when brake and power pressed. I hear some sounds that are typical to when i press the brake pedal, hard to describe, but from the dash area more like a whirrìng or humming sound and a "dink dink dink dink" but deep and faint...I hear relays. Click when i open the driver door, that's it.
    Other clues: headlights work fine, door lights on when doors open, interior lights functional, key fob unlocks but here's something interesting, it seems to think the key is in the car, even when standing quite far away when I try to lock it it makes that sound that says "nope, keys in the car!" The lock and unlock on the door panel works however. Mirrors arent. Currently adjustable

    doorQUOTE="Tombukt2, post: 3476732, member: 188908"]So when you push the start button with the brake pedal depressed you're not hearing the clicking of the relays in the back of the car that you've been hearing as long as you've owned the car?[/QUOTE]
     
    #4 Cypress650, Aug 31, 2024 at 2:22 AM
  5. Cypress650

    Cypress650 New Member

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    It does nothing. For reference, I've checked every single fuse change. They are all fine including the feasible lengths under the hood and the one twenty one that is attached to the positive on the battery.
     
    #5 Cypress650, Aug 31, 2024 at 2:23 AM
  6. Cypress650

    Cypress650 New Member

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    Sorry I meant to say fusible links
     
    #6 Cypress650, Aug 31, 2024 at 2:24 AM
  7. hurricos

    hurricos Junior Member

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    > Another possibility is that a capacitor on the Combination Meter (speedometer) circuit board has failed which prevents the CM from turning on (& can affect the normal "power on" sequence).

    This is the big one. I'll note there can be temporary stateful faults that persist so long as there's 12V power to keep components on the CM and throughout the car running; I had issues with my CM board after my 12V depleted last winter (the power button would shut the CM off but the car on, and vice versa), and I ultimately solved them by charging my 12V to full outside the car, then putting everything back together. Once the meter and the rest of the car are in sync, things will work.
     
    #7 hurricos, Aug 31, 2024 at 12:44 PM
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