2007 Prius touring, Traction battery diagnosis and repair

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Robert Golden, Apr 8, 2026 at 7:16 PM.

  1. Robert Golden

    Robert Golden New Member

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    Location:
    Tucson AZ
    Vehicle:
    2007 Prius
    Model:
    Three Touring
    Which, if any, of these traction battery cells need replaced?

    April 7, 2026 hybrid battery voltage: 14.48, 14.29, 14.24, 14.05, 14.32, 13.84,
    14.07, 13.49, 13.05, 14.07, 14.10, 14.19,14.26,14.52
     
  2. JC91006

    JC91006 Senior Member

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    II
    if these are readings from the original 2007 battery, it's best you replace the entire battery with a used "newer" battery. The battery will need replacement modules and reconditioning. And even after that, it may not last very long if it's from 2007 (nearly 19 years old)
     
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  3. pasadena_commut

    pasadena_commut Senior Member

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    There is a whole long process for reconditioning modules. The voltage at one time point is not the whole story. (Well, unless there is obviously a shorted cell.) For instance, there might be two modules that happen to be at the same voltage right now but have wildly different resistances. The pack will quickly go out of balance in that case. These packs do not like heat, and Tucson is even hotter than it is here. The pack on our 2007 was replaced a couple of years ago. I wasn't going to bother trying to recondition a battery that old, an OEM one was put in instead.

    One caveat, does the OP know that the pack is OEM inside? Toyota might not return the core charge if the innards are different. For instance, there are packs which use cylindrical cells. I don't know if they will take a pack which has the lithium ion modules in it.