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How worried should I be?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by wingkongex, Jan 14, 2019.

  1. wingkongex

    wingkongex New Member

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    Hey guys, first time long time.

    Recently had the red triangle pop up on my '07 Prius with only 76k miles on it when turning on the car yesterday afternoon. Took it into the dealer today, they pulled down code P0A9C only.

    They added that they observed "Battery TB1 at 62.2, while others were at 98.4 and 87.4." After clearing the code, they drove it for around 30 miles and the light did not return.

    How screwed am I here? Obviously they suggested replacing the battery if the light appears again, which I will not be doing (through the dealer at least) but I figured I'd see if anyone has experience with this code and what my options may be.

    Thanks in advance.
     
    #1 wingkongex, Jan 14, 2019
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    DTC P0A9C points to a problem with a battery temperature sensor. The sensors are not separately available as a Toyota part. Hence if you were to fix this problem without replacing the battery, it would be necessary to remove the traction battery, disassemble the unit, find the failed sensor, and see if you can separately source that part.
     
    #2 Patrick Wong, Jan 14, 2019
    SFO likes this.
  3. wingkongex

    wingkongex New Member

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    Interesting. So, basically drivable but could damage the battery in the long run if it's not properly reading the temps?

    I should mention that after driving it, they said the temps read normally. Any tools you would recommend me to use to keep on eye on this?
     
    #3 wingkongex, Jan 14, 2019
  4. SFO

    SFO Senior Member

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    Welcome to PriusChat!!

    Here is the workup for DTC P0A9C, P0A9D, P0A9E :

    http://ww2.justanswer.com/uploads/skyvisions/2008-06-21_094242_05_prius3.pdf

    If you can take the battery apart, you could replace the sensor harness with a used one.

    Not sure how screwed you are, but keeping your battery cool will help it last longer (see my sig below). If you didn't get a HV battery through the dealer, who would you get a replacement battery from?

    Though your vehicle only has 76k, it might be a good time to clean the HV battery fan. Especially if you carry pets or smokers around.
     
    #4 SFO, Jan 14, 2019
    Last edited: Jan 15, 2019
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  5. stockdaddy

    stockdaddy Member

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    There are multiple battery sensors so it would depend if the Prius can still adjust fan speeds with one bad sensor.

    The battery needs to get over 140F before it can cause serious damage.
     
    #5 stockdaddy, Jan 27, 2019
  6. yi3o8

    yi3o8 Junior Member

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    Sorry to rvivr this thread. Has this code came back on or did you need to replace the temp sensors at all??

    Posted via the PriusChat mobile app.
     
    #6 yi3o8, Feb 8, 2020
  7. MB31

    MB31 Junior Member

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    The code did not come back
    I did not start this thread but had the same fault code recently and it did not come back after a reset. However today after a couple of weeks without trouble it threw a P0A80 so am screwed after all. Took the car to a hybrid mechanic who mentioned that the P0A9C can be a precursor of the P0A80. So in my case I will be replacing the batterypack...
     
    #7 MB31, Feb 11, 2020
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