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2004 Prius Battery Problems

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by eddieherrera, Apr 30, 2018.

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  1. eddieherrera

    eddieherrera New Member

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    So I have a 2004 Prius and recently the "triangle of death", the ABS light, and check engine light came on so i took it to a buddy to scan it his his OBD reader it said i have to replace the hybrid battery i then do a diagnostic check within the car and the battery is reading around 11.6V when the car is off when the ignition is off (whuch seems to be a little under what it should be) and when the IG is on it is at 14V (which is where it should be i believe). i have no idea what to do can anyone with the same problem or have a clue help.
     
    #1 eddieherrera, Apr 30, 2018
  2. ericbecky

    ericbecky Hybrid Battery Hero

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    Would be good if you could load test the 12v.
    But in any case, if this is a car you planning on keeping it might be worth spending a little money ($75?) on some diagnostic tools.
    Elm 327 Bluetooth OBDII reader
    Android phone/tablet
    Torque Pro app

    Then you could read and clear error codes, plus see live data like hybrid battery voltage etc.

    It certainly could be the HV Battery. Do you know what cores are present? For example P0A80.
     
    #2 ericbecky, May 1, 2018
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  3. bisco

    bisco cookie crumbler

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    welcome!
    start with a cold reading of the 12v. use a meter on the jump point under the hood. 11.6 is very bad, how old is it? has it ever had to have a jump?
     
    #3 bisco, May 1, 2018
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  4. dolj

    dolj Senior Member

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    This will not be IG-ON, but READY. Even though the modes are covered in the owner's manual, few seem to have read it.

    Prius power cycle modes:
    Mode
    Action​
    1 ACC
    • With the car in OFF; and the foot OFF the brake; press the start button once.
    2 IG-ON
    • If the car is in OFF; with the foot OFF the brake; press the start button twice.
    • If the car is in ACC mode; with the foot still OFF the brake; press the start button once more.
    3 READY
    • With foot ON the brake; press the START button once; this can be done when the car is in any other mode.
    4 OFF
    • If the car is in READY; press the START button once; it does not matter whether the foot is on or off the brake.
    • If the car is in ACC mode; with the foot OFF the brake; press the start button twice.
    • If the car is in IG-ON mode; with the foot OFF the brake; press the start button once.
     
    #4 dolj, May 1, 2018
    Last edited: May 1, 2018
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  5. edthefox5

    edthefox5 Senior Member

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    You seem to saying the hybrid battery is the 12 volt battery. It is not. The hybrid battery
    Is the very big and expensive battery. Hundred and hundreds of posts about it and if it’s the original hybrid battery it is almost certainly bad given its age.

    What code did the car throw?
     
    #5 edthefox5, May 1, 2018
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  6. eddieherrera

    eddieherrera New Member

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    so i ended up doing a lot of research and it was the very expensive hybrid battery that was the issue. what i ended up doing is take apart the back of my car and opening the hybrid battery and with a multimeter i found out that i have one really low one (6.40) and i believe they should be at around 7.6. the thing is i have a few at the low 7.5 range. should i replace just the 6.40 or am i going to have to replace all of the low (7.54, 7.53,7.50,7.30). thanks for all the help
     
    #6 eddieherrera, May 20, 2018
  7. eddieherrera

    eddieherrera New Member

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    so i ended up doing a lot of research and it was the very expensive hybrid battery that was the issue. what i ended up doing is take apart the back of my car and opening the hybrid battery and with a multimeter i found out that i have one really low one (6.40) and i believe they should be at around 7.6. the thing is i have a few at the low 7.5 range. should i replace just the 6.40 or am i going to have to replace all of the low (7.54, 7.53,7.50,7.30). thanks for all the help
     
    #7 eddieherrera, May 20, 2018
  8. bisco

    bisco cookie crumbler

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    if you are going to play whack a mole, i would at least load test the cells. but you would be better off reading one of the battery rebuilding threads here, and making a proper job of it.
     
    #8 bisco, May 20, 2018
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  9. Raytheeagle

    Raytheeagle Senior Member

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    You need to replace the one at 6 volts;).

    If you will only be swapping out the one module without charging and balancing the pack, you’ll be doing this again, and again and again:(.

    The others could be okay for the short term if you balance them for a period of time. But you’ll need to continue that effort ;).

    As @bisco said, search is your friend so you can read up on the rebuilt pack threads :).

    Good luck and keep us posted (y).
     
    #9 Raytheeagle, May 20, 2018
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  10. ericbecky

    ericbecky Hybrid Battery Hero

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    Get some diagnostic tools and use the data to see what portion of your battery is failing.

    Build or buy a charging/discharging system to balance the pack.
     
    #10 ericbecky, May 20, 2018
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  11. eddieherrera

    eddieherrera New Member

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    any good videos on how to balance them? or any tips
     
    #11 eddieherrera, May 22, 2018
  12. Raytheeagle

    Raytheeagle Senior Member

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    You want to do all of them at once, or individually :whistle:?

    If all together, Hybrid Automotive sells the Prolong equipment that makes the process easy;).

    If you want to do individually, plan on spend a couple of weeks charging and discharging individual modules until all 28 are done :(.

    There are plenty of videos on YouTube about this though;).

    Good luck and keep us posted (y).
     
    #12 Raytheeagle, May 22, 2018
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