Force battery fan to high speed without app?

Discussion in 'Gen 2 Prius Technical Discussion' started by LKasdorf, Sep 4, 2021.

  1. LKasdorf

    LKasdorf Junior Member

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    My gen 2 seems to be having trouble keeping the battery cool on a hot day.
    A few weeks ago on a hot day, the red triangle came on with a P3000 and P0a80
    The cooling fan was quite dirty and I cleaned it.

    It happened again today. Same thing.

    I know that with hybrid assistant, I can set the cooling to be more aggresive. And supposedly with torque but I've never quite figured it out.

    But I think that I'd need to keep the app connected to ODB and running for this to happen, right?

    Is there a way just force the fan to high speed without an app?

    I do have an old version of techstream also- can it be done there?
     
  2. SFO

    SFO Senior Member

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    What HV battery temps are you seeing on a hot day, and are you parking the vehicle outside with the windows up?

    The only way to override the HV battery fan without using an App would be to hard wire the needed voltage to the fan.

    Pretty sure you can use techstream to step through the HV battery fan speeds, but as above you would need to leave in connected.

    It may be a good idea to you run the AC when the outside temps are above 75F.

    Have you removed the HV battery cover to inspect the the voltage sense loom or HV battery ECU connectors for corrosion?

    DTC P3000 should have a few associated INFs (subcodes or detailed codes), what does techstream offer for such?

    How many miles on the vehicle / HV battery?
     
  3. LKasdorf

    LKasdorf Junior Member

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    Earlier today I was reading 129 F batt temp and 110F inlet temp. I looked just now and it says batt temp 123, inlet 91, even tho the outside temp is 79. I set Hybrid Assistant to aggressive cooling and let it run for a while with fan on 6, and I could hear the fan, but it didn't seem to drop in temp like I'd expect.

    This is a 2005 with `180k or so, and a Dorman battery installed by prev owner. I have replaced about 6 cells and re-balanced it. The battery has been working great since I did this a year ago, but recently started this overheating issue.

    My first thought is that maybe I didn't get the temp sensors installed correctly- but it has worked for a year since I was in there.

    I have 3 2nd gen Prii and have installed a grid charger on each. If I open it up again, I'll look for corrosion on connectors.

    I don't know what this means: "DTC P3000 should have a few associated INFs (subcodes or detailed codes), what does techstream offer for such?"

    Thanks for responding!
     
  4. burrito

    burrito Member

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    He means that you should hook up Techstream to read the error codes. The P3000 error code will have 1 or more sub-codes set, which will help diagnose why P3000 is set.
     
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  5. mr_guy_mann

    mr_guy_mann Senior Member

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    P3000 means "you have a code in the battery ecu- go look over there". P0A80 is the battery ecu saying "I saw the HV battery block voltages vary too much- Toyota says you should replace the HV battery". Toyota also has a subcode (or " inf" code) for some diagnostic trouble codes that can give more details about what is going on. Often you need an "advanced" scantool (such as Techstream) to view inf codes.

    You can use some sort of scantool (or OBD2. Bluetooth adapter with Dr Prius or Hybrid Assistant app) to monitor block voltages and see what it is that the ecu doesn't like. Usually, a temperature or cooling problem by itself will not set a P0A80.

    Posted via the PriusChat mobile app.
     
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  6. TMR-JWAP

    TMR-JWAP Senior Member

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    You can always check air flow at the outlet in front of the 12v battery. See how much air is coming through and get a temperature check on it.

    The possibility always exists that you have a bunch of gunk on top of the modules blocking air flow. When people have dirty/clogged fans, some of that junk got through the fan before it became totally clogged. Usually ends up on top of the modules.
     
  7. dolj

    dolj Senior Member

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    Use Hybrid assistant to see what the internal resistance (IR) of each block is. My hunch is some are over 30 mΩ. If IR is high you pretty much are looking at replacing them.
     
  8. LKasdorf

    LKasdorf Junior Member

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    I have techstream on this car now. I did a health check, and here is the screen.
    PXL_20211001_205508997.jpg
    Clicking on the first blue splat (P3000) shows this:
    P3000_splat.jpg
    Clicking on the P0A80 blue splat shows this:
    p0a80_splat.jpg
    Battery block V05 is low, but would this really cause these codes and the red triangle?
    I have swapped in cells on this battery, and I can swap out some more.

    BTW- I didn't see a way in hybrid assistant to see the battery cell's internal resistance, as was mentioned in an earlier post.
     
  9. TMR-JWAP

    TMR-JWAP Senior Member

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    Battery block V05 is low, but would this really cause these codes and the red triangle?

    Yes, and block 8 should also a concern
     
  10. mr_guy_mann

    mr_guy_mann Senior Member

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    I don't bother much with the "internal resistance" data- it's just calculated from the voltage readings and amps. The voltage difference from the highest to lowest blocks is what the ecu looks at.

    Posted via the PriusChat mobile app.
     
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