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12v issue/inverter pump

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by insaner, Sep 17, 2019.

  1. insaner

    insaner Junior Member

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    2007 Prius
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    I live in Atlanta and it’s been HOT for quite a while, with record temps these last couple weeks in September. Yesterday after my car sat all day I went to drive someone downtown and when I got in the car and depressed the brake and went to start it, the dash lights acted sort of funny and the ready light didn’t come on. I shut it off and tried again and on the second press the ready light came on. Drove fine after that. It did it again this morning and so after dropping off my first ride I went and had the 12v tested and it read 9.6v so I knew what the culprit was. Oddly though, when I started it to leave autozone and head to the dealer for a new battery is said “hybrid system overheated” on the maintenance panel. I have read where a bad inverted coolant pump can fail a 12v. This is the original battery in the car and it has 142k miles so I’m sure the battery was bad I’m just wondering if you guys think it would’ve been due to the inverter pump it that the battery being dead made the message kick on. Or perhaps it is just a sad coincidence and the pump is also bad? I’m at the dealer now getting the battery put in. I’ll check for coolant flow when they’re done, just wanted an opinion.

    Thanks.
     
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    First, congratulations on that battery making this far. This is your 2007? You're right about it being due anyway.

    After the new battery is in, you can test the inverter cooling pump by:

    With your foot NOT on the brake, press the power button 2 times. The first time will energize the MFD. The second will energize the remainder of the dash, and is called "ignition-on" condition. In this state, the inverter cooling water pump should be running, but the engine will not start. It allows you to look in the reservoir for ripples, without having to worry about engine vibrations interfering.

    After checking:
    If you press the power button one more time (with your foot off the brake) the car will turn off.
    If you press the button with your foot ON the brake, it should go to ready mode.
     
  3. insaner

    insaner Junior Member

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    Battery is in and car seems fine. Fluid shows movement in the reservoir and no overheat message.
     
  4. insaner

    insaner Junior Member

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    Oh and this is my 2013, I guess I haven’t updated my info. 2007 made it 287k before brake issue showed up a month offer the extended warranty was done. Sold it and bought this 2013.
     
    bisco likes this.
  5. bisco

    bisco cookie crumbler

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    a low battery can make the computers do funny things. hopefully, that's all it was.

    might be worth checking the intake grille and cooling fan though.
     
    insaner likes this.
  6. Jetlifekc

    Jetlifekc New Member

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    2010 Prius
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    Should the inverter pump be running if the inver converter has failed. I am having a p0a1a and p0a1b code and just noticed i don't have any movement in my inverter coolant resivour maybe this was why it failed?