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Won't start -- hard to figure out why.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by zmre2b, Dec 21, 2009.

  1. zmre2b

    zmre2b Junior Member

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    Background: no problems with the '05 Prius with now 100k miles. Drove it Friday; parked it in garage. On Saturday, I moved the car up a few feet in the garage to move it and left the smart key sitting the cup holder as I often do. I'm pretty sure that I turned the car off as I didn't notice the car ever running or the lights on (I usually leave the headlights on, so if the car is on the lights are on and I can tell). Although it is possible that I did leave the car in the on or acc position -- although I think unlikely.

    I go to start the car this morning and with key sitting in the cup holder and get nothing from the start button. I think that's odd and maybe something is wrong with the key sensor or key battery so I put the key in the slot.

    With foot on the brake and pressing the start button I get some life from the dash (but not the MFD) but no starting. the full range of check engine, stability, etc. lights come on, the fuel gauge first seemed to read about a half a tank and then was flashing alternating between a flashing single bar and full. The transmission lights were flashing with the boxes around each of the gear selections.

    The MFD never showed anything. I think I heard a pump of some kind from the engine but not sure. Various combinations of pressing the start button and pressing and not pressing the brake pedal never started the car and for a long time I couldn't even shut it all down. I was stuck in a limbo with the key was locked in the slot with the start button light on and various other lights on. Finally after pressing some more, I got the key released and it seems to be all shut off. I was in a hurry and took another car but need to deal with this tonight.

    Possibilities:

    1) battery charge drained somehow and isn't sufficient?
    2) out of gas sensor either screwed up or I'm really out of gas and is preventing starting? (This happened once before, although I can't recall how much gas was in the car this weekend.)

    Any other ideas? or tips?

    thanks for any help.
     
    #1 zmre2b, Dec 21, 2009
  2. qbee42

    qbee42 My other car is a boat

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    You have a dead 12V battery. Either you left something on, or the battery is just getting old.

    Either way, you can jump start from the jump points under the hood. Be very, very careful to not reverse the polarity (positive to positive, negative to negative). I know this sounds obvious, but people have done thousands of dollars worth of damage to Gen II Prius by reverse jumping.

    Once you jump it, it will run fine until you shut down again, so keep your Prius in Ready mode for a couple of hours to get the battery charged up again, or put the battery on a charger.

    If problems continue, or you measure and find low voltages, it may be time for a new 12V battery.

    Tom
     
    #2 qbee42, Dec 21, 2009
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  3. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    If not for this very detailed and excellent paragraph, I would have passed over this as a technical issue I can't help with. But as it is, I've drained my 12v three times since 2004* and the flashing transmission lights and the funky gas gauge as you describe them are exactly what I've seen every time. As for not getting the key out of the slot, I had to leave the car unlocked with the key in it overnight in the driveway but wasn't really concerned because it's not like it was going anywhere.

    So I have to agree with Tom. Unfortunately, depending on how you parked in the garage, jumping might be difficult. It is possible to manually open the hatch but not easy. You will need to search the forums or Google for that one. If you only have the standard large jumper cables you might have problems. After my third jump* I went out and bought a set of the "mini cables" which a coworker had. They are awesome at getting to the [+] terminal under the hood which is a very tight fit.

    Good luck, sorry about the battery and keep us posted.




    *Yes, I've drained my 12v three times. No, none of them were on purpose. Yes, I'm blonde. Get over it.
     
    #3 TonyPSchaefer, Dec 21, 2009
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  4. Rokeby

    Rokeby Member

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    zmre2b,

    All of the individual symptoms that you have noted are symptomatic of
    the 12V battery being the cause of your troubles. On the fuel gauge; it
    gets very "confused" at low voltages. If you still have the original 12V
    battery, it is at the typical service life of ~4 years. It may have been
    on its last legs anyway. And that may have been enough on it's own. :(

    However...

    As to why this may have happened, it was probably leaving the SKS
    fob in the car, even though the car is "Off." Remembering that your
    12V battery may have had marginal capacity to begin with, any small
    load over a longish period of time, overnight in this case, would be
    enough. That small, continuous load may be the car holding itself in a
    "standby to start mode" because of the fob being inside the car.

    I'm being a little speculative on this "standby" thing.
    If I'm wrong I know some smarter folks will correct me. :rolleyes:

    Here's why I think this is the answer: If I sit in the car with the fob in
    my pocket, I can hear quiet quiet sounds of stuff happening in the car.
    I haven't hit the Power button. But the car "knows" that you are there;
    the drivers door was opened, there is a weight on the drivers seat, the
    SKS signal is strongest from the inside the car antenna. Also, at times
    my ScanGauge comes to life, apparently as the result of some HSD
    related messaging on the HSD bus.

    Again, I think it's time for a new 12V battery...
    and in the future keep your fob in your pocket. ;)
     
    #4 Rokeby, Dec 21, 2009
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  5. qbee42

    qbee42 My other car is a boat

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    Rokeby is correct. Leaving an SKS fob in range of the car will shorten the life of the fob battery and increase the load on the 12V car battery.

    Tom
     
    #5 qbee42, Dec 21, 2009
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  6. richard schumacher

    richard schumacher shortbus driver

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    #6 richard schumacher, Dec 21, 2009
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  7. zmre2b

    zmre2b Junior Member

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    thanks all. A quick jump from a portable battery charger/air compressor to the battery in the trunk did the trick. I think it's easier to jump from under trunk instead of the hood. certainly cleaner anyway. will get a new battery at next oil change and will stop leaving the key fob in the car. thanks.
     
    #7 zmre2b, Dec 22, 2009
  8. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    Resolution! Hurray!
    Yeah, it sounds like you really stretched the life of that battery. It's served well, no doubt, but it's time to trade it in.
     
    #8 TonyPSchaefer, Dec 22, 2009
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