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master+brake+abs+vsc warning lights on start

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by tnvu, Apr 9, 2012.

  1. tnvu

    tnvu Junior Member

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    Title says it all. Occasionally when I try to start my 2007 Prius (70k miles), the master warning light along with the brake, ABS, and VSC warning lights all come on. I'll turn my car off and then turn it back on and it will start right away.

    One thing that I notice is that it seems like the headlights and/or the MFD is dimmer than usual when this happens. I'll turn off the headlights, turn on the car, wait for it to start, and then turn on the headlights and everything will work correctly.

    Any ideas on the next steps I should take?
     

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    #1 tnvu, Apr 9, 2012
  2. jdcollins5

    jdcollins5 Senior Member

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    Check your 12V battery voltage after sitting for a few hours. If below 12V you need to look in to replacing the battery.

    These are typical signs of a 12V battery issue. Especially with the headlights and MFD being dimmer. Also if this is the original battery it is time to replace anyway.
     
    #2 jdcollins5, Apr 9, 2012
  3. tnvu

    tnvu Junior Member

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    Thanks for the tip. I left the car overnight. This morning, I hooked up my generic bluetooth OBDII scantool and pulled up the Auxillary 12V Battery. I hit the power button twice (IG-ON, without my foot on the brake). The initial voltage was around 9.6V. I then cycled the headlights on/off a couple times and each time the voltage dropped to 8.8V. I then switched the car ON (power button and pressed brake) and the voltage jumped up to 14V and then flattened out around 13.8V for the duration of my trip (10miles and around 10 minutes on the highway).
     
    #3 tnvu, Apr 9, 2012
  4. jdcollins5

    jdcollins5 Senior Member

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    Replace your battery now ! Before it leaves you somewhere other than your driveway.

    The 14 and 13.8V was the internal charging system trying to recharge your battery and supply 12V to the internal electronics, etc.
     
    #4 jdcollins5, Apr 9, 2012
  5. tnvu

    tnvu Junior Member

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    Yup thanks for the help. I ordered one of the YellowTop from Advance Auto Parts. $200-$50 (code: VISA).

    I've been reading through the forums and feel pretty comfortable replacing the battery myself. I was wondering if there is a way to preserve my settings when I replace the battery. I've seen people asking about using various trickle chargers, battery chargers, portable jump starters, but haven't seen any definitive instructions on this. Any pointers for that?
     
    #5 tnvu, Apr 9, 2012
  6. jdenenberg

    jdenenberg EE Professor

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    Just change the battery, you will only have to reset the radio, clock and maybe the auto up-down front windows.

    JeffD
     
    #6 jdenenberg, Apr 9, 2012
  7. tnvu

    tnvu Junior Member

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    Thanks for the info JeffD. I'd still like to try to preserve my settings. Let me know if this plan is crazy (or dangerous).

    1) My portable jump starter has a 12V female cigarette outlet to act as a battery, rated up to 15A (which should be way more than needed when the car is off).
    2) I am planning on getting a male-to-male cigarette adapter along with a female cigarette-to-alligator clip adapter. (I couldn't find a male cigarette adapter to alligator clips.)
    3) I'll clip in my jump starter to the posts under the hood. The portable jump starter should act as a 12V battery through the posts under the hood.
    4) I'll then replace the 12V auxiliary battery in the trunk according to instructions.
    5) Then disconnect the jump start pack. The power then should be drawn from the new 12V auxiliary battery.

    It seems that this should preserve my settings. Let me know what you think.
     
    #7 tnvu, Apr 10, 2012
  8. jdenenberg

    jdenenberg EE Professor

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    Just make certain that the positive battery cable in the hatch doesn't touch anything while it is disconnected from the battery. You can blow a fuse.

    JeffD
     
    #8 jdenenberg, Apr 10, 2012
  9. jpadc

    jpadc Type before I think too often

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    There is also a $25 rebate from Optima for purchases in April. Check their site or some other places in the Gen II forums for a link to it. They are practically giving that battery away these days :D
     
    #9 jpadc, Apr 10, 2012
  10. kocho

    kocho Member

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    How many years do people get out of their Gen II batteries, typically (if there is such a thing as "typically")? Mine is at the end of the 4th year and wondering if I should take advantage of the rebates and just keep the Optima as a spare till the time comes... I can trickle-charge it from time to time to keep it in shape until needed, I suppose. Would that be a good idea or just wait until the Prius starts complaining?

    EDIT: found this thread http://priuschat.com/forums/gen-ii-...ting/106037-typical-lifetime-12v-battery.html that answers my question, sort of ;)
     
    #10 kocho, Apr 13, 2012
  11. seilerts

    seilerts Battery Curmudgeon

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    A scrap yard will give you around $7 for a battery. There is no sense in buying an Optima and letting it sit on a shelf.

    A good rule of thumb is this: If your car more than three years old, and you have a problem with the 12V (dome light left on etc), just replace it. Younger batteries may be able to be fully trickle recharged. Older batteries weaken significantly over time and it usually takes only one deep discharge to do them in.
     
    #11 seilerts, Apr 13, 2012
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