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Electrical gremlins!

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Acidbass32, Aug 29, 2016.

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  1. Acidbass32

    Acidbass32 Member

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    Alright folks I have an issue and I'm starting to get worried. Let me set the scene. I started using my spare keyfob because the one I had been using for years was starting to get a little worn, well after I started using the other keyfob, when I would press the power button to turn my car off, EVERYTHING would die (no interior lights coming on, no shifter display on the dash like you normally see when you power your car off, etc.). so I would take the key out, open the door and suddenly the car would power on again and everything would reset. My aftermarket stereo, my head unit MPG average, AC, and fuel gauge. Needless to say this is really peculiar and I have no idea what is going on. I couldn't find anything similar online regarding this problem and don't want to take it to the dealer if its some simple fix. Thanks for the input.
     
    #1 Acidbass32, Aug 29, 2016
  2. Kevin_Denver

    Kevin_Denver Active Member

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    For weird electrical problems on the Prius, first thing to check is the 12V battery. What are the voltages after it's:
    1. Sat overnight
    2. Turn on car to ACC-ON and turn on headlights for at least a minute, then turn off car and read voltage
    3. In ACC-ON with headlights on
    4. In Ready

    As you probably know 1st should be > 12.5, 2 and 3 should be >12.2, and 4 should be >13.5. Less than that points to a failing 12V battery which could be causing the issues.

    Otherwise my best guess would be that one of the main relays in the car is starting to fail, perhaps shorting to ground, causing a large enough voltage drop to reset all of the electronics.

    If you use a code reader that read Toyota specific codes (e.g. Techstream), does anything show up?
     
    #2 Kevin_Denver, Aug 29, 2016
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  3. Acidbass32

    Acidbass32 Member

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    I don't have a techstream, I'll run a volt meter to it tonight and see whats up.
     
    #3 Acidbass32, Aug 29, 2016
  4. Acidbass32

    Acidbass32 Member

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    Alright so I turned off the car to go into Walmart and the entire car died, the locks weren't working or anything. I loosened and retightened the positive terminal on the battery in the hatch and it went into ACC mode immediately. I'm thinkin. A new battery is needed? Taking it to the dealer tomorrow.
     
    #4 Acidbass32, Aug 29, 2016
  5. bisco

    bisco cookie crumbler

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    sounds like a plan. is it the original?
     
    #5 bisco, Aug 29, 2016
  6. Acidbass32

    Acidbass32 Member

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    I believe so
     
    #6 Acidbass32, Aug 29, 2016
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  7. Kevin_Denver

    Kevin_Denver Active Member

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    It sounds like it, but I'm not certain. I would want to confirm that the battery voltage was low. When the battery is disconnected and reconnected it should stay off, not turn on again.

    Also surprised you're taking it to a dealer first, based on the amount of work you've done on your car, it seems that taking a voltmeter to the battery and replacing it would be a walk in the park for you.
     
    #7 Kevin_Denver, Aug 29, 2016
    Last edited: Aug 29, 2016
  8. Acidbass32

    Acidbass32 Member

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    Well that's what it's been doing, instead of my jostling the positive cable in the back around its just been coming back on in ACC mode when the door opened or closed or just a few seconds after it went completely dark. I mean the battery would make sense, but to double check I'm going to take it in first thing
     
    #8 Acidbass32, Aug 29, 2016
  9. Acidbass32

    Acidbass32 Member

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    I have to go to the the dealer for trans fluid replacement anyway since my friend can get me in before my classes tomorrow.
     
    #9 Acidbass32, Aug 29, 2016
  10. bisco

    bisco cookie crumbler

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    with an 8 year old battery, i don't care if it's the problem or not, i'm changing it.
     
    #10 bisco, Aug 29, 2016
  11. Acidbass32

    Acidbass32 Member

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    Yeah but I want the issue resolved, not just throw a band aid on it
     
    #11 Acidbass32, Aug 29, 2016
  12. bisco

    bisco cookie crumbler

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    of course. 12v won't be a band aid, it will either fix it or it won't. i'm just saying replace it before you have more problems.
     
    #12 bisco, Aug 30, 2016
  13. The Electric Me

    The Electric Me Go Speed Go!

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    If that's the original 8 year old OEM battery?
    I'm placing ALL my bets on 12 volt battery.
     
    #13 The Electric Me, Aug 30, 2016
  14. Acidbass32

    Acidbass32 Member

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    The more I am researching it, the more I am thinking it is the 12 volt. I am at the dealer right now so fingers crossed.
     
    #14 Acidbass32, Aug 30, 2016
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  15. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    Don't take this the wrong way, but why would you take the car to the dealership for a 12V battery replacement???
    From the pictures I've seen you post, you're more than mechanically inclined enough to perform this simple task.

    Your call......but if it's me, I'm getting one and installing it myself.

    As far as why an 8-year-old aux battery may fail???
    Uh.....
    "Mods- GReddy vehicle monitoring system, dipped rims, ECU tune, rotor enlargement, LED light bar, Morimoto H1 6.0 projector headlight retrofit with demon eyes and switchback halos, Tanabe sustec front underbrace, Tanabe strut tower brace, Juiced Hybrid Chassis stiffener, Hella supertone horns, Pioneer double din head unit, 6.5" Kicker 3 way door speakers, Alpine tweeters, Kicker 10" comp S subwoofer, Boss audio 3700 watt 5 channel amp, Yakima whisbar roof rack system, Curt cargo roof bin, 2008 Toyota Matrix TRD rear sway bar, 2008 Toyota Corolla Front sway bar, OEM 2008 Toyota Corolla front sway bar bushings, KSport Kontrol coilovers, vinyl wrapped interior, RGB rock lights, LED pod fog lights, roof mount LED light pods, rear roof mount LED pods, Uniden bearcat CB radio, Auxiliary PA system, firestik 2 foot CB antenna and many more to come."
     
    #15 ETC(SS), Aug 30, 2016
  16. Acidbass32

    Acidbass32 Member

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    Like I said in a previous reply I had an appointment anyway for an alignment, and trans fluid replacement. I know I have a lot going on in the car, but I never have all of it running when the car is off, or even when it is on for long periods of time so it would contribute to the failure but I don't think it is the root issue. This started happening before I ran the roof lights a few days ago anyway, so I would much rather be safe than sorry.
     
    #16 Acidbass32, Aug 30, 2016
  17. Acidbass32

    Acidbass32 Member

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    Alright so my buddy threw a tester on the battery and there was a dead cell in the starting battery (which is expected). Used his car to grab and optima yellow top while he was doing my alignment and trans fluid change, and now the car is happy hopefully.
     
    #17 Acidbass32, Aug 30, 2016
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  18. bisco

    bisco cookie crumbler

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    all the best!(y)
     
    #18 bisco, Aug 30, 2016
  19. Acidbass32

    Acidbass32 Member

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    so far so good, had a 30 mile drive on the highway at 84mph no signs of anything when I turned it off. Guess I'll see when I go grocery shopping later.
     
    #19 Acidbass32, Aug 30, 2016
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