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Discharged Prius

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by drbenson, Aug 25, 2004.

  1. drbenson

    drbenson New Member

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    My wife just had a scary experience in her brand new '04 Prius. She stopped at a rest stop on her trip back from California to Washington. used the facilities, crawled in back to sleep for a couple of hours (it was 3am). When she woke up and tried to continue, she said she saw a very dim 'engine malfunction' light, and the car refused to start.

    She called Toyota Roadside Assistance. They sent a tow truck, and the driver and she learned together how to jump start a Prius. The driver said the Roadside Assistance covered only up to $100 towing, so she decided to drive to the nearest Toyota dealership. In the morning they checked the car, put it on diagnostic, and found nothing.

    Now she's afraid to turn the car off, trying to get home on caffeine, and swears she hates the car and will never take it farther than around town again. Any ideas from the assembled collective wisdom as to what might have caused this debacle? Any similar experiences?
     
    #1 drbenson, Aug 25, 2004
  2. efusco

    efusco Moderator Emeritus
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    Almost certainly she left something turned on in the car...either it was in IG-ON mode or the accessory mode at least. The little 12v battery just won't handle that kind of drain.

    I'd have the 12v checked, it may not be in good shape, but there's nothing wrong with the rest of the car.
     
    #2 efusco, Aug 25, 2004
  3. V8Cobrakid

    V8Cobrakid Green Handyman

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    That's too bad your wife had to experiance that. You might want to check the center console. Ever throw coins in their? it's possible for something to have shorted out the 12V plug.. have them checked.. those little plugs are not perfect.. they do get flaws every once and a while. When they do your diagnostics, they should have checked the current draw when the car is off. They should be able to tell you right away what's wrong, if they do that.

    I agree to have the battery checked. Little tiny battery. If somehow it was drained before for some reason.. it's weakened now. I get the feeling Toyota didn't do a very good diagnostics job. They probably plugged in to the computer to see what it said. Not everything is computer. Some things have to be done by hand.
     
    #3 V8Cobrakid, Aug 25, 2004
  4. efusco

    efusco Moderator Emeritus
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    You know what? I was thinking about this a little more. I KNOW it was her fault that the battery died. If there were lights on on the dash then the car had to be in one of the power on modes...either ACC or IG-ON...was she using the vent/A/C or listening to the radio or something? I am sure she must have been. If the battery had simply discharged itself somehow with the car totally off there would have been nothing showing on the display at all when she woke up from her nap.
     
    #4 efusco, Aug 25, 2004
  5. drbenson

    drbenson New Member

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    Not sure lights were on in the dash before she tried to start, but I have come up with this scenario:

    Pulled up to the rest stop, lights on. Got out of the car, lights off automatically when car door opens. Got back into the car, turned aux on to lower a window a bit for ventilation. Turned car back off. Would this have turned the lights back on? If so, we may have found the problem. Haven't had a chance yet to test this scenario on my car.

    Is it the concurrence of opinion that a once-discharged 12v should be replaced?
     
    #5 drbenson, Aug 25, 2004
  6. V8Cobrakid

    V8Cobrakid Green Handyman

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    Even if you were to turn the car on to lower the windows.. when you turn the car back off.. the lights might turn on in the inside.. but they would go back out after about 10 seconds or so. This should not have drained your battery.

    As for replacing the 12V.. no.. when you took it to the dealer ( which i would be guessing to be soon after it happened) they would recharge it and it should be fine. They would know if it's bad.. or.. they should know.. some dealers aren't too bright sometimes. As long as the car is starting up.. it's probably fine.

    I was just thinking about the ACC.. and IGN ON modes... ACC is first right? can you do the windows with this?... what if she turned everything off.. when in ACC mode.. and rolled the windows down.. pressed the pwer again which sent it into IG-On.. now.. the hybrid system will not work.. but the system is still sucking energy.. a couple hours of this might drain it.

    Either way.. it's a guessing game. Just make sure she knows about the power modes.. and that the engine can only turn on when the car is actualy on ( brake + Power button )... you can rest like this.. you may burn up some fuel if your battery gets low.. but only if you have the AC on.. if not, then you should be able to listen to just the radio for quite a while.
     
    #6 V8Cobrakid, Aug 25, 2004
  7. drbenson

    drbenson New Member

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    Was thinking about the *headlights* going back on when switching through ACC and IGN, then staying on when the car is switched off. She insists she was NOT listening to radio, using fan, etc- power switch was off, headlight switch MAY have been in 'on' position, but switched off by opening door.

    I'll be able to test my scenario in a couple of hours, and I'll post for the edification of all, to prevent a similar stranding for someone else!
     
    #7 drbenson, Aug 25, 2004
  8. V8Cobrakid

    V8Cobrakid Green Handyman

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    I wish you could ask the car.. hehe.. o well.. good luck with it. It is possible that the headlights turned on when she rolled the windows down.. and then stay on.. but i don't know how long they would stay on for.. either way.. goodluck.. let us know how your test come out.. i'll repeat your test for you if you like.. just to test a different habbit when it comes to driving.
     
    #8 V8Cobrakid, Aug 25, 2004
  9. hdrygas

    hdrygas New Member

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    Could her foot been on the brake turning on the brake lights. I remember napping in a similar situation only to have some knock on the window to tell me to move my foot or my battery might go dead. Doesn't take much pressure to engage the light in most cars. Just a thought.
     
    #9 hdrygas, Aug 25, 2004
  10. bruceha_2000

    bruceha_2000 Senior Member

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    He said she crawled in back, so I would guess that means she wasn't sitting in the driver's seat. I find it interesting that this could happen. If there was enough power to show a dim "Engine Malfunction" warning, why would that not be enough to start the car since 'start' means powering up the computer, not cranking a starter motor. Or does the little 12V have to do more than that?
    Yet another example of why Toyota should at least have a switch that allows you to 1) charge the 12V from the traction battery or 2) start the car from the traction battery so the ICE can recharge the 12V
     
    #10 bruceha_2000, Aug 26, 2004
  11. V8Cobrakid

    V8Cobrakid Green Handyman

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    I'm suprised it did not start up.. but a few circuits will require at least a little bit of stable power. As for charging the 12V.. once the car "start" the hybrid battery will charge the 12V.. it's programmed to keep it charged when the car is on.
     
    #11 V8Cobrakid, Aug 26, 2004
  12. drbenson

    drbenson New Member

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    My wife and I went over my 'scenario' above, and she agreed that's exactly what happened- the particular sequence of actions led to leaving the lights on, thus dead battery.

    The upside is that she learned to nap with the car 'on' and in park- better ventilation, and an automatic one-hour wakeup nudge when the engine turns on.

    Thanks to all for the help and advice. Hope her experience will save someone else from a drained Prius!
     
    #12 drbenson, Aug 27, 2004
  13. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    DrBenson,
    Thanks for sharing your experience with all of us. I find it extremely insightful to read about others' experiences. I may not need this nugget of information right away, but when I do I'll be darn glad I read it.
     
    #13 TonyPSchaefer, Aug 27, 2004
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