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Can a new 12V reading high, cause Ignition Coil to misfire?

Discussion in 'Gen 3 Prius Main Forum' started by analoggirl, Aug 29, 2024 at 5:09 PM.

  1. analoggirl

    analoggirl Junior Member

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    IMG_9971.jpeg IMG_9970.jpeg IMG_9969.jpeg I replaced a 12 V with a Toyota battery last week. The car was shaking like crazy on start up this morning, check engine light is now on. I stopped at AutoZone to run codes. See the pictures for results. I'm wondering if the fact that my 12 V is reading at 14.17 V Caused any issues?

    2011 Gen3, 206,000 I replaced the main hybrid with Toyota battery last year, water pumps and brake pump also replaced in last year with Toyota parts.
     
    #1 analoggirl, Aug 29, 2024 at 5:09 PM
  2. bettergolf

    bettergolf Active Member

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    Most likely you have a head gasket needing repair/replacement. Major work...sorry. Battery reading 14.7 is normal and would not cause a problem.
     
    #2 bettergolf, Aug 29, 2024 at 5:45 PM
    Brian1954 likes this.
  3. Tombukt2

    Tombukt2 Senior Member

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    You didn't read up on these beforehand yeah you're heading for all kinds of fun I envy you not
     
    #3 Tombukt2, Aug 29, 2024 at 6:18 PM
  4. bisco

    bisco cookie crumbler

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    That reading is the inverter charging the battery
     
    #4 bisco, Aug 29, 2024 at 6:46 PM
  5. analoggirl

    analoggirl Junior Member

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    So I'm befuddled, how is a 12 V battery reading 14.x
     
    #5 analoggirl, Aug 29, 2024 at 7:34 PM
  6. analoggirl

    analoggirl Junior Member

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    but it's 14+ whether it's been sitting off, or after I turn it on for 30 minutes. Never below 14. And why would a 12 V battery stay at 14+
     
    #6 analoggirl, Aug 29, 2024 at 7:36 PM
  7. bisco

    bisco cookie crumbler

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    If the car is off, a new agm battery should measure close to 13v
    I’m wondering about your meter
     
    #7 bisco, Aug 29, 2024 at 7:49 PM
  8. Tombukt2

    Tombukt2 Senior Member

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    If you're checking the car's battery while in ready mode you will see about 14.5 volts now turn the car off Wait 20 minutes take another measurement it'll be around 12:00 If it's under 12 that's problematic You need 12 volts in the 12 volt system not 11.9 or any of that
     
    #8 Tombukt2, Aug 29, 2024 at 8:01 PM
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