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Prius won't start

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Enoblk, May 1, 2016.

  1. Enoblk

    Enoblk Junior Member

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    I replaced the hybrid control ECU that had it immobile for the past year or so. Drove it around for about 30 minutes and realized a tie rod was bent and put it in the shop, came out the next morning and nothing in the car would work except for lights and thing that work with the car off.
    When I go to start the car the start button light is off and pressing it does nothing.

    Charged the battery
    unplugged it for 5 minutes
    Checked most of the fuses
    Tested the battery
     
  2. Enoblk

    Enoblk Junior Member

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    I was checking the battery for a parasitic drain and accidentally checked the voltage between the negative cable and the negative post and it was around 9 volts, i am not sure if that's normal
     
  3. bisco

    bisco cookie crumbler

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    me neither. how about the voltage between positive and negative with everything off, a few hours after charging?
    also check the connection from battery negative to ground.
     
  4. Enoblk

    Enoblk Junior Member

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    The voltage between positive and negative was about 12.7 volts
    And there was a drain of 500ma that goes away by pulling the dome fuse
     
  5. bisco

    bisco cookie crumbler

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    does the dome light work?
     
  6. Enoblk

    Enoblk Junior Member

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    Ya dome lights and headlights work
     
  7. bisco

    bisco cookie crumbler

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    did you talk to the shoppe guys? did they drive it out, or was it dead inside when they were done?
     
  8. Enoblk

    Enoblk Junior Member

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    It hasn't been to a mechanic in several years, I've been working on it myself
     
  9. bisco

    bisco cookie crumbler

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    sorry, when you said put it in the shop, i thought you meant somewhere else.
     
  10. Enoblk

    Enoblk Junior Member

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    Nope, drove it around, it would start and shut off when I wanted it to. Put it in our shop, came out the next morning and it wouldn't start
     
  11. bisco

    bisco cookie crumbler

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    could someone have disengaged the safety plug?
     
  12. Enoblk

    Enoblk Junior Member

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    No, and the MFD would still turn on if it was, all the electronics that start before it says ready run off the 12v
     
  13. bisco

    bisco cookie crumbler

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    any possibility something wasn't connected tightly in the edu you worked on?
     
  14. Enoblk

    Enoblk Junior Member

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    Checked the connections last night
     
  15. bisco

    bisco cookie crumbler

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  16. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The voltage should be zero. Measure the resistance of the cable when disconnected.
     
  17. Enoblk

    Enoblk Junior Member

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    0.1 ohms resistance on the 4in negative cable
     
  18. Enoblk

    Enoblk Junior Member

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    Changed the newer steering control module back to the old one and started up
     
    Andyprius1 likes this.
  19. andrewclaus

    andrewclaus Active Member

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    Here's my guess: When you put the voltmeter in series with the negative cable, you basically put a very high resistance in the circuit and were measuring the voltage drop across it. The "parasitic load" was trying to complete its path through the tens of thousands of ohms of the voltmeter, rather than the near zero ohms of the ammeter. The total voltage drop in the circuit must equal the battery voltage, so the electronic loads in the car were only getting about three volts, and only a fraction of a milliamp was flowing.
     
  20. bisco

    bisco cookie crumbler

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    exactly what i was thinking.:cautious: