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Prius engine isn't coming on and charging battery

Discussion in 'Gen 2 Prius Main Forum' started by ricksterbusa, Jun 21, 2020.

  1. ricksterbusa

    ricksterbusa Junior Member

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    Vehicle:
    2007 Prius
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    Over the last month I've noticed that when I'm parked, my engine is not coming on to charge the battery. When I'm in park, the battery indicator can go down to 2 brown bars within 7-15 minutes, even with the AC and everything else off. Normally the engine should come on (every 7 or 8 minutes I've heard) and charge the battery, and it used to come on periodically and lurch and scare the holy crap out of me, but for some reason now when I'm in park, the engine is not coming on and charging the battery, and it's letting it drain all the way down to the to brown bars. I have to put the car in drive and go drive around and then very quickly it seems to get back to a normal or full charge. But when I put it in park, even with everything off, the battery slowly drains down. Why isn't the engine coming on to charge the battery?
     
    #1 ricksterbusa, Jun 21, 2020
    ydpplqbd likes this.
  2. bisco

    bisco cookie crumbler

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    welcome!
    sounds normal to me. what happens if you stay in park with the a/c on full blast?
     
    #2 bisco, Jun 22, 2020
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  3. fotomoto

    fotomoto Senior Member

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    Not normal.

    Possible signs of a weak/failing HV battery that has lost capacity.

    GOOD LUCK!
     
    #3 fotomoto, Jun 22, 2020
    ricksterbusa and jerrymildred like this.
  4. ricksterbusa

    ricksterbusa Junior Member

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    2007 Prius
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    If the air conditioning was already on, the engine will stay on for a bit, then it will turn off and not come back on. If I turn it on, the engine may come on for a minute or 2, but if the engine shuts off, it won't come back on, even if the battery drains down...isn't that weird?
     
    #4 ricksterbusa, Jun 24, 2020
  5. bisco

    bisco cookie crumbler

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    not sure, i think so. so if you sit there with the a/c on, eventually, the a/c is going to stop working, the engine is going to come on, or the car is no longer ready, and you'll get a dashboard full of lights.
     
    #5 bisco, Jun 24, 2020
  6. TMR-JWAP

    TMR-JWAP Senior Member

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    Vehicle:
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    The engine will not start running immediately every time the SOC indicator drops to 2 bars. There are times the SOC will be showing 2 bars for minutes before the engine starts. If you have an app to provide an actual SOC %, you would probably notice the engine starts every time around 40-43% SOC. The car knows what to do. If it doesn't know what to do, it will code out.
     
    #6 TMR-JWAP, Jun 24, 2020
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