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Battery Block 1 Showing 0.0 V

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by aplee, Aug 12, 2021.

  1. aplee

    aplee New Member

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    Hello,

    2011 Prius Gen3 w/ 100,000 miles

    Here are my error codes:

    P0B3D: Hybrid battery voltage sensor A - circuit low
    P0A80: Hybrid battery pack Deterioration
    U0155: Data bus, instrumentation control module - no communication

    I have used two OBDII scanners. The first only displayed the P codes. The second displayed all three.

    Interestingly, the battery scans display block 1 as 0.0 V. I've read that a reading of 2.5 V and below results in a display of 0.0. However, this obviously isn't the case. So far, I've:

    1. Checked the 12 V battery. It's good.
    2. OCV (no-load) tested the modules. All good.
    3. CCV (load) tested the modules through the Dr. Prius app. All good except block 1, which reads 0.0 V.
    4. Cleaned the connectors and bus bars.
    5. Replaced the bus bar harness and sensing wires. (I saw corrosion in the connector and thought it may be preventing it from communicating with the HV battery ECU.)

    I'm <$100 into the problem and have acquired some useful tools and knowledge, so I'm not freaking out. I still get 40 MPG. The U0155 error code just popped up an hour ago; so far, the only solutions I've read involve replacing the 12 V battery. As for P0B3D, my next assumption is to try replacing the HV battery ECU.

    That being said, I'm also an actual simian. Do you have any further thoughts or insight, Prius gods?
     
    #1 aplee, Aug 12, 2021
    Last edited: Aug 12, 2021
  2. PriusCamper

    PriusCamper Senior Member

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    A common problem that gives bad voltage sensor readings is the voltage sensing harness gets corroded and shorts out where it plugs into the battery ECU, but looks like you've eliminated that problem. Though looking inside the ECU for a signs of damage seems to still need to be done.

    Then next step is to get a voltage reading from each of the 28 individual modules and put it on a spread sheet. Then next step would be to measure the voltage drop of each module after 2 minutes of being connected to a 12v 50w light bulb. A healthy module will only drop by .3 to .4 volts depending on if module needs reconditioning or not. Then next step is to replace bad modules, maybe get a hobby charger to recondition and further test modules would be wise too... I could go on and on... But probably better to keep it brief and wait for your next post to say more.
     
    #2 PriusCamper, Aug 13, 2021
  3. bisco

    bisco cookie crumbler

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    maybe just sneak in under the warranty?
     
    #3 bisco, Aug 13, 2021
  4. PriusCamper

    PriusCamper Senior Member

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    If you need help with that, here's a pic of how me and @bisco used to do it:

    Screenshot from 2021-08-13 18-29-27.png
     
    #4 PriusCamper, Aug 13, 2021
    Mendel Leisk and bisco like this.
  5. aplee

    aplee New Member

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    Ah, up until now I was hoping to avoid that in the hopes that the problem lies elsewhere; my theory being that, even if a module is going bad, the block wouldn't straight up display 0.0 V. I'll take that advice though and post here with the results.

    As far as the warranty, I've exceeded the 8 years and don't have much hope that a dealership would extend that olive branch.
     
    #5 aplee, Aug 14, 2021
  6. dy/dx

    dy/dx Junior Member

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    I have the same problem. Did you find a solution?
     
    #6 dy/dx, Sep 18, 2021
  7. ChapmanF

    ChapmanF Senior Member

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    There wasn't ever any mystery here ... there was the P0B3D clearly saying the sensing of voltage from block 1 was busted, and along with that, for some reason, block 1 showing an unrealistic voltage reading.

    For anyone else genuinely having the same problem (that is, a code for any of the voltage sensors being out, whether or not you also notice the weird reading for that sensor), it's fixed by opening the battery and repairing the sensor damage.

    In a Gen 3, frustratingly, Toyota doesn't sell that sensor wire harness separately. There seem to be some PriusChat members who do repairs and have surplus ones available though.
     
    #7 ChapmanF, Sep 18, 2021
  8. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    When you weren’t helping him pulverize cookies with toy cars, on that wall?
     
    #8 Mendel Leisk, Sep 18, 2021
  9. aplee

    aplee New Member

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    Yes. I replaced the HV battery ECU. I took apart my original ECU and saw that one or two of the lines on the PCB from the senor wiring connector was blown (may or may not be fully blown out - I can still trace continuity through the line, but I haven't tried to put it back in to see if it would still work after cleaning it up. My new used one works perfectly fine, anyway.)

    The voltage reading on block 1 returned to normal. And I learned more than I ever wanted to about HV batteries. I feel like I can make one out of rocks now.

    Sorry for the late reply. I had a last-minute deployment come up and just recently got back.
     
    #9 aplee, Nov 6, 2021
    Catherine Kourouklis likes this.
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