Triangle of death, Dr Prius interpretation

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Josh L, Mar 28, 2025.

  1. Josh L

    Josh L New Member

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    TLDR: Bad Battery Voltage Sensor? Something else?
    Screenshot_20250328-161449[1].png Screenshot_20250328-161454[1].png

    Background: I bought a 2010 w/ 220,xxx miles with known bad head gasket and Check Hybrid System light on. CEL was P0301 and I can't remember but think P0A080, checked w/ Dr Prius. I cleared all the codes after new HG, but after a week no codes have returned. ICE runs almost constantly.
    Batt Temp2 and 3 don't change from 170.8F and -25.1F, Temp1 seems correct. Voltages jump form 1.33V to 69.08V. When checked manually all blade pairs are between 15.76 and 15.88. Is this a bad Battery Voltage Sensor? Power Management Control ECU? Related wiring harness? Something else?
    Thanks in advance!
     

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  2. PriusCamper

    PriusCamper Senior Member

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    Clean out corrossion inside ECU and replace temp senor wires and voltage sensor wires... See link in my signature for voltage sensor wires.
     
  3. jacktheripper

    jacktheripper Senior Member

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    Pretty sure the battery voltage sensor unit (battery ECU) has burnt out by all the corrosion. @Josh L replace the battery ECU, wire harness first and clean up all the corrosion.
     
  4. Brian1954

    Brian1954 Senior Member

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    What Bluetooth dongle are you using with the app?
     
  5. Josh L

    Josh L New Member

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    @PriusCamper and @jacktheripper, thanks! I forgot to say I took the Battery Voltage Sensor apart and didn't find any corrosion or broken solder joints. I also tested all 4 thermistor resistances, at 68F they were between 10.9k and 11.7k ohms. I'll look into the voltage wire harness next.
    @Brian1954 I'm using a new, cheap ELM327 Bluetooth dongle. No issues on two other cars, but maybe that doesn't mean much.
     
  6. MAX2

    MAX2 Senior Member

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    In the event that one of the temperature sensors shows a high temperature, the battery fan turns on and begins to blow intensively on it so that it cools down.
    The hybrid system goes into emergency mode, the internal combustion engine works, the hybrid part is not used.
    It is necessary to figure out whether the sensor is really recording such a temperature or whether a false signal has occurred due to a line break or corrosion of the connector and wires.
    You need to inspect the insides of the high-voltage battery.
    Also change your scanner, which gives non-existent values for voltage and temperature.
     
  7. Josh L

    Josh L New Member

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    Thanks Max2, if the hybrid system shuts down I would expect poor acceleration and high fuel consumption, neither of which I'm experiencing. The Check Hybrid System should also illuminate, do you have any insight why mine isn't after a week?
    I have a post waiting for moderator approval, sorry some of this will be redundant. There's no corrosion on the BVS or connectors, and I don't see any broken solder joints. Thermistor resistances are between 10.9k and 11.7k ohm at 68F.
    PXL_20250329_123838993.jpg PXL_20250329_123853101.jpg PXL_20250329_123920009.jpg
     
  8. PriusCamper

    PriusCamper Senior Member

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    Did you inspect and clean inside the battery ECU? That will be where the problem is if the wires check out.
     
  9. Brian1954

    Brian1954 Senior Member

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    So you used the dongle on two other cars (hybrids) while using the Dr Prius app, and the data shown was realistic?

    Is your ELM327 Bluetooth dongle on the list of the ones tested to work well with the Dr Prius app per their website?

    Please provide the manufacturer and model number of the one you are using?

    I have seen screenshots posted by other members on this forum with unrealistic data. I believe it is being caused by the Bluetooth dongle. Can you record a video showing the Dr Prius app as you drive the car and create a link to your video?
     
    #9 Brian1954, Mar 29, 2025
    Last edited: Mar 29, 2025
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  10. MAX2

    MAX2 Senior Member

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    I agree with @Brian1954
    Excessive values may arise due to imperfections of the adapter, which is not designed to work with the Dr. Prius application.
     
  11. Josh L

    Josh L New Member

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    Thanks @Brian1954 and @MAX2. The Bluetooth adapter is indeed the issue. It works fine for CEL's on ICE cars but doesn't work well with Dr. Prius. I just received a new PanLong adapter and everything seems normal.
     
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  12. MAX2

    MAX2 Senior Member

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    You no longer have error and problem indications on your dashboard? Then everything is great!
     
  13. Josh L

    Josh L New Member

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    That's right, no lights on dash after a month of daily driving!