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2007 Prius 158k miles intermittent start

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by OnGrace, Mar 12, 2018.

  1. OnGrace

    OnGrace New Member

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    The whole 3 month history...

    I purchased the car in December. It has had one owner, Carfax clean.

    1st fix - January. The combination meter had to be fixed because the car wouldn't turn OFF, and thanks to PriusChat and YouTube, that was done for less than $100. At that time I had checked the voltage on the 12V battery, and it read good.

    About a week ago, it won't turn ON. The tow truck driver ends up jumping the car, and I take it in to a local auto shop. They say the car is fine - just a loose battery connector. They said the battery is fine - they checked it as well and said I did not need a battery replacement.

    After the shop visit, I noticed that the keyless entry didn't consistently work (even pushing this black buttons on the car), and that the smaller lights below the headlights didn't come on anymore.

    1520887165735.jpg 1520887171094.jpg 1520887202269.jpg

    1520887142557.jpg

    I took it on a long trip (eight hour drive each way) and it died twice on me.

    The first time, I was away from it for about an hour (after driving eight hours). When I came back and pushed the Power button, there was nothing. No accessories on, no beeping. But cabin lights seemed to function.

    So I recruited a good Samaritan to help me jump it - no go. We tried with his car on idle for five or so minutes. Before he left, to show me that the battery was indeed charged, they guy touched the two ends of the jump cables together while it was attached to my car battery. Sparks. Battery charged...

    Local garages were about to close, but I called one, while said it may be HV battery.

    I get off the phone with them, push Power button - it turns on. I run the simple battery test (push Power once, no brake, hold Display button while turning lights on/off 3 times), and it looks good. 12.8 V battery reading.

    It turns on and off just fine as I drive home the next day, except again about 8 hours after driving. I make a pit stop, less than 5 minutes, get back to the car - no go.

    Eventually I repeat what the guy did - attach jump cables to the battery in back of the car, touch the leads. At first, no spark. So I thought the battery really is dead this time. Then, it sparks. Push the power button. It turns ON. I drive straight home (another 4 hours).

    I stop by the same auto place today (borrowed car) to let them know. Basically, if they can't get the car to do this while it's at their shop, there's nothing for them to fix. They want to send me next to a Toyota Dealership.

    I haven't started my car again, but this morning the keyless entry works (lower front lights do not). I didn't even lock it again just so that I don't f#*$ anything else up crossing wires or something.

    Please help. Dealership alternatives welcome, as they seem to charge way more for their services, possibly enough to drain my bank account at this point.

    Posted via the PriusChat mobile app.
     
    #1 OnGrace, Mar 12, 2018
  2. JC91006

    JC91006 Senior Member

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    replace your 12v battery.......

    although they said it tested good, you really can't test a Prius battery that easily. It first has to be fully charged using less than 10A (takes hours), then you do a load test. If they didn't do that or they put over 10A to charge, they could have damaged the battery or not noticed it's weak.

    I recommend the cheap replacement of the 12v first
     
    #2 JC91006, Mar 12, 2018
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  3. dolj

    dolj Senior Member

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    AND STOP CROSSING YOUR JUMPER LEADS!

    Pardon? What?

    I said, STOP CROSSING YOUR JUMPER LEADS!

    You are lucky your didn't blow the 100 A fuse, which will cost $1000s to repair.

    The fog light (the smaller lights below the headlights) issue is just probably a fuse or next possibility the bulbs have blown. You never said what you've done to troubleshoot that.
     
    #3 dolj, Mar 12, 2018
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  4. OnGrace

    OnGrace New Member

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    Ok. Just changed out battery today and seems to be good. Wonder why the auto place said battery was fine... Will revisit this if things go south again. Thanks for the help.

    No more crossing jumper leads-got it. But from what I am reading, Prius 12v batteries run or are used differently than for full gas vehicles. Does this mean I should not jump my car? Or also, I should never use my car to jump someone else's?

    Posted via the PriusChat mobile app.
     
    #4 OnGrace, Mar 13, 2018
  5. Dxta

    Dxta Senior Member

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    You could jump your car, but it has got procedures. I don't have the manual right now.
     
    #5 Dxta, Mar 13, 2018
  6. dolj

    dolj Senior Member

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    Correct, and as Dxta said, you can jump your Prius, just follow the correct procedures.
     
    #6 dolj, Mar 13, 2018
    Last edited: Mar 14, 2018
  7. exstudent

    exstudent Senior Member

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    Multiple factors:
    1) AGM batteries should have a higher resting voltage than traditional "wet" cell batteries.
    2) The store could have used a small load tester.
    3) Many load testers base good/bad in terms of CCA (Cold Craning Amps); this is useless for a Prius b/c the 12V battery does not crank the engine to start, unlike traditional vehicles.

    READ the owners manual. If you don't have it, get it from Toyota.com/owners
    OK to receive a jump. NOT recommended to give a jump.

    IIRC, the 12V bus on the Gen2 Prius has an output of 3-4Amp hr charge rate. A fully depleted SKS battery (45Amp Hr), would take 45/3 a theoretical 15hours to become fully charged. However, once the battery is severely discharged as yours was, it is damaged, and reliability becomes suspect.

    Get a DVM (Digital Volt Meter); better accuracy.

    Is my inverter coolant pump slowly failing? | PriusChat
    Post #5 - How to apply a load for a more meaningful 12V battery reading.
    Post #8 - SOC (State of Charge) table and Smart AGM compatible battery chargers.​
     
    #7 exstudent, Mar 14, 2018
  8. OnGrace

    OnGrace New Member

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    To note:

    1. I did allow someone to jump their car once in January, not knowing any better.

    2. The simple battery test was done right after driving the car for about 15 mins, not first thing in the AM, so it might have given a false high, like Post #8 talks about.

    So, given that and that the auto shop may not have tested the battery appropriately, it seems like that is indeed the fix. Thank you for all the help.

    Posted via the PriusChat mobile app.
     
    #8 OnGrace, Mar 14, 2018
  9. OnGrace

    OnGrace New Member

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    #9 OnGrace, Mar 14, 2018
  10. OnGrace

    OnGrace New Member

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    ... hit the button too soon...

    I just did the test per Posts #5 and #8, with accessories on, and the car had been resting all night. 11.3V, changed to 11.4V after a few seconds. This is with a brand new battery (Super Start Platinum).

    Posted via the PriusChat mobile app.
     
    #10 OnGrace, Mar 14, 2018
  11. OnGrace

    OnGrace New Member

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    And I read the manual about jump starting just now. It doesn't say anything about not jumping someone else's car, but I will not do that again just in case.

    Posted via the PriusChat mobile app.
     
    #11 OnGrace, Mar 14, 2018
  12. johnjohnchu

    johnjohnchu Active Member

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    I never had any issue jumping other people's cars over the years.
     
    #12 johnjohnchu, Mar 14, 2018
  13. OnGrace

    OnGrace New Member

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    Just went to O'Reilly - they did a battery/alternator check, but the guy said unless the check engine light is on, an OBD2 reading wouldn't show anything. So, that's all for now, I guess.

    Posted via the PriusChat mobile app.
     
    #13 OnGrace, Mar 14, 2018
  14. dolj

    dolj Senior Member

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    Happens all the time. But you just hit the edit button and carry on, no need to start a new post.
    Well, something is not right. A new fully charged battery should be in the region of 13 V, not under 12 V. So, first off get that battery charged fully, then repeat the test.
    Pfft, and they call themselves professionals. What a crock. Like to hear them explain how an alternator test works on a Prius.
     
    #14 dolj, Mar 14, 2018
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