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P3000 after a long struggle

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by UTadventures, Jul 16, 2024.

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  1. UTadventures

    UTadventures Junior Member

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    This is a bit of a TLDR, but I am stuck.
    2008 w/180k. I replaced a few modules about 18 months ago, and had no issues until about 5 weeks ago. I chose to try to recondition the cells (and utilize my best cells and the best of the lot I bought last time). After almost 4 weeks of cycling cells with great results I replaced the worst and reinstalled the HV battery. Alas, the 12v was seriously discharged, and a quick jump got it started. All codes gone. Drove and ran for 20ish minutes. When I turned it off, everything was dead again. Repeated a jump with no issues, then put the battery on a charger and tested it after a second run (5.7v, yikes). Anyway, trickle charged for 2 days and reinstalled. Started right up, but then immediately threw the P3000 (makes me think it’s not a cooling issue.)
    I do not have Techstream, but free DrPrius, and CarScanner apps.
    Here’s what I’ve checked:
    Other than the code, drives as normal (though fuel gauge is also blinking empty despite being very full)
    HV Battery 220 v
    All cells have greater than 4.0 Ah capacity, majority well over 5.0.
    All cells within 0.12v after cycling up to 80% and down to 20%(balanced for a week waiting for the bus bars)
    12v: 12.4v engine off
    All new bus bars and nuts
    All connections and related fuses (high desert car with zero rust)
    Hybrid pack cooling blower works (tested at 12v, and from 0.8-2.0 amps)
    oh, and I noticed when raising the temperature of the battery fan threshold, the red triangle stays off, until the temps rise and the car tries to turn the blower on. Then the code is thrown again within 5 seconds.
    This is my third/ fourth time battery out, so it’s easy now, BUT,
    What am I missing?
     
  2. bisco

    bisco cookie crumbler

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    have you checked the battery cooling fan connector for pin corrosion?
     
  3. UTadventures

    UTadventures Junior Member

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    Yes, zero corrosion on any connections, just on the copper bus bars, which were replaced with zinc coated ones.
     
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  4. UTadventures

    UTadventures Junior Member

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    Update as of 7/14/24@11:23 Utah time. I checked the voltage to the hybrid battery fan motor connection. 0.0 volts when the car is on, but no cooling is required, then using Dr Prius app to set a lower temp, I clicked it on. I can instantly hear a click of the relay (all clean connections), and the voltage jumps to 13.85. But I hook up the motor, and nothing (besides a thrown code). So it’s gotta be the motor, right? Except when I bring the motor in and hook it up to my hobby charger that can output any voltage and amperage, it blows air. Set At 12v and 1 amp, it is drawing about 0.95 amps. I hate to throw parts at it, if the motor works. Connections are clean on both ends. Still stumped…
     
  5. rjparker

    rjparker Tu Humilde Sirviente

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    Measuring power in circuit to chassis ground or to the blower’s ground wire? Bad continuity to ground or even the two control wires could be the issue.
     
    #5 rjparker, Jul 17, 2024
    Last edited by a moderator: Jul 18, 2024
  6. UTadventures

    UTadventures Junior Member

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    Thanks! I’m no electrician- but have basic understanding. I held the red on the + connection that would touch the + on the motor, and the black to the - side. I can hear the relay functioning when the fan is activated. When it’s not, (open circuit), I got a varying couple mV at most, and then it jumped right to 13.85V when working. But will not run the motor.
    I did the same to the motor from my charger, and it runs.
    If the relay is keeping the circuit open until needed, it shouldn’t have continuity until “on”, correct?
    Heading out after breakfast to see if I can find/ test any of those circuits.
     
  7. UTadventures

    UTadventures Junior Member

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    Getting 13.90 V at the motor connection, but zero continuity, with relay and fan “on” and code thrown.
    Motor has continuity.
    13.97 V at the positive motor connection, and negative on chassis ground.
    IMG_1016.jpeg IMG_1017.jpeg IMG_1021.jpeg IMG_1022.jpeg

    Tested the relay too, and got resistance on the silver tabs. 170-300ish Ohms if I remember.
    IMG_1018.jpeg
     
  8. rjparker

    rjparker Tu Humilde Sirviente

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    Opps- gen3 wiring instead of gen2. In any case checking continuity means check a wire from beginning to end.
     
    #8 rjparker, Jul 17, 2024
    Last edited: Jul 18, 2024
  9. mr_guy_mann

    mr_guy_mann Senior Member

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    So, the previous diagram doesn't match any Gen2 I've seen. The blower is supplied 12V power from the relay (but only when the blower is commanded on). The blower has a variable ground from the blower motor controller, which receives a signal from the battery ecu. There is no direct ground for the blower.

    The yellow, brown, and violet wires go to the ecu.

    The white "known-problem" connector is this one near the motor (here the two corroded terminals have been spliced into the black connector) If there is corrosion, it means that there is a body leak around the tailgate hatch due to cracked seam sealer. Screenshot_20240717-192318.jpeg tapatalk_1683289052331.jpeg

    Posted via the PriusChat mobile app.
     
  10. UTadventures

    UTadventures Junior Member

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    That diagram makes MORE sense to me, as there are two connected green wires and two connected purple wires supplying power to the motor connection. However, there is literally zero corrosion anywhere on the car (except the old copper bus bars and nuts, which were replaced). 2% humidity has its advantages. Here’s my “known problem” connector ends:

    IMG_1040.jpeg IMG_1041.jpeg

    The variable ground makes sense in theory, especially with no real ground. However, I’m still confused why a command to turn on the fan produces proper voltage supply to the motor, but won’t turn the motor, when supplying 12V from a hobby charger makes it work fine.
    Where might I test for continuity without tearing the wiring harnesses and sheathing all apart? The “battery blower motor controller”? Is that in the pile of electronics I see in the open battery case?
     
  11. UTadventures

    UTadventures Junior Member

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    Continuity exists between the like colored wires of the relay, fan power supply and “known problem” connector.
    I could not get any like colored wires from the male fan power or “known problem” connectors to show continuity, but only tested purple, yellow, and green, as per the diagram - in this picture, at the connectors.
    The likelihood of ALL wires being bad seems small…but I have never tried that before and maybe just got it wrong. Plus these connectors have much smaller access for the probes, so maybe I just didn’t make contact, but I don’t want to break anything. IMG_1042.jpeg
     
  12. Tyler.b

    Tyler.b New Member

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    I just posted about fixing pin corrosion. My battery cooling fan is not running and I found extensive corrosion on the connections (see pics). How do I go about fixing this?
     

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  13. dolj

    dolj Senior Member

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    Most people just cut the brown and black wires at both ends and bridge them around the plug. If you wanted to keep the disconnect feature (for whatever reason) buy a 4-pin waterproof plug and socket connector and replace the OEM plug and socket. In any case, there is no need to overthink it. Getting the brown and black wires reconnected will fix your problem.

    A tube-shaped connector (built-in heat shrink) with two crimps for splicing the wires in line would be preferable to solder and heat shrink.
     
  14. UTadventures

    UTadventures Junior Member

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    Thank you to everyone that helped - the saga is over! (For now). After testing everything I could think of, looking over the wire looms, connections (zero corrosion), and even borrowing a mechanic friend’s very expensive Snap-On OBD reader, I could only see that the voltage to the hybrid battery cooling fan was a little high. (Dr Prius did not see this code). I went through the checklist on this link: Toyota Prius P3000: Check This Before Replacing Your HV Battery | Torque News Replaced the relay, and was ready to order a new motor, when I checked the connection to the motor controller - disconnected. Though it still ran down, under the vent and looked connected. Oh my goodness…that was it. Reconnected, blower works, cleared codes, took it for a drive. Done. Sheesh.
     
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  15. rjparker

    rjparker Tu Humilde Sirviente

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    Sounds like the old Assume bug struck once again.

    It’s usually the simple thing after someone has been in there fat fingering. This is where a drawing, a meter and troubleshooting technique can make short work of an issue.