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Ignition system draining battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by stevemcl, Apr 1, 2018.

  1. stevemcl

    stevemcl Junior Member

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    I have an 04 and the battery has been dying. Put a voltmeter on the battery and started pulling fuses. #31 fuse is the one drawing. It is the ignition system. The car started to beep after the key was out like it was still in. This morning I hopped up a jump box and the instrument panel and radio came on without a key. Any suggestions are appreciated.
     
  2. bisco

    bisco cookie crumbler

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    try shutting off sks.
     
  3. sam spade 2

    sam spade 2 Senior Member

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    That is probably a sign that your battery is worn out and needs to be replaced.

    Without knowing how MUCH drain there is with everything OFF and with the doors closed and waiting 30 minutes or so......there is no way to tell if there is anything really wrong or not. There IS some normal drain when off but that is very small.

    If/when the battery gets weak, even that very small drain might make the voltage drop more than it should.
     
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  4. stevemcl

    stevemcl Junior Member

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    I had the battery tested and it has a bad cell. New one will be here tomorrow. I'll put that in and see what happens, thanks.
    .
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Check milliamps when the car's idle too. Disconnect the negative cable, connect one longish wire to the negative post (either directly or to the cable, depending on how you disconnected), and another longish wire to bare metal on the body. Run them out through the hatch threshold, gently close the hatch on them, wait say 20 minutes, then hook up multimeter to the other ends of both wires (in series), with meter set to amps. If nothing displayed (there shouldn't be), switch to highest milliamps scale (unless it's autoranging, then just switch the once) and gradually step down till you get a reading.

    Around 15~20 millamps is the norm I think, that's what I was seeing anyways, with my 3rd gen. With occasional spikes to around 40.
     
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  6. sam spade 2

    sam spade 2 Senior Member

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    Good.
    Be sure the new battery is fully charged BEFORE being put into service.
     
  7. bisco

    bisco cookie crumbler

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    i must say, i don't really understand how the car started without a fob in range.
     
  8. sam spade 2

    sam spade 2 Senior Member

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    Wow. Guess I need to get my glasses checked.
    I can NOT find that information in any of the posts in this thread.
     
  9. bisco

    bisco cookie crumbler

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    second to last sentence:
    'this morning i hopped up a jump box and the instrument panel and radio came on without a key'.
     
  10. sam spade 2

    sam spade 2 Senior Member

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    Does that indicate that it entered the "ready" mode and was drivable ?
    I highly doubt it.
    If not, I don't think that qualifies as "the car started".
     
  11. bisco

    bisco cookie crumbler

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    i'll wait to hear back from o/p, interpretation can be futile.
     
  12. Mendel Leisk

    Mendel Leisk Senior Member

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    You're quite fluent in auto-correct. (y)
     
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