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P0A94

Discussion in 'Gen 2 Prius Main Forum' started by Bilewis1994, Apr 17, 2020.

  1. Bilewis1994

    Bilewis1994 New Member

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    Hi one and all,

    I have a 2008 Prius that I've rebuilt the Battery pack several times. My daughter has borrowed it and every time she hit a big bump in the road the red triangle of death comes up. I've gotten many codes: P0A94, P0A68, P0AE7, P0ADC. Looking at this code I decided to replace the DC inverter to no avail. I took it out and hit a bump and the car drops to what I believe in 2nd gear. Sucks on the highway. When I got home I banged on the 12v battery to see if it has an issue. None! Then I banged on the hybrid batteries and caused a P0A94. I can reproduce this every time. I'm going to open it up a start tapping on everything to narrow down or find the cause. My question is has anyone seen anything like this?

    Thanks
     
    #1 Bilewis1994, Apr 17, 2020
  2. bisco

    bisco cookie crumbler

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    sounds like you didn't torque the nuts, or a loose/corroded wire or connection

    try a bigger hammer
     
    #2 bisco, Apr 17, 2020
    ydpplqbd likes this.
  3. TMR-JWAP

    TMR-JWAP Senior Member

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    I would say the odds are pretty high that there's a loose/bad connection somewhere in the electronics portion of the HV battery.

    Not sure what led you to go right into inverter replacement. P0A94 has like 25 possible subcodes, but all related to the inverter. BUT, the inverter isn't going to work very well if the HV battery is turning on and off when you hit a bump. Did you really look at the other codes? Bumps typically cause loose connections to act loose....focus should be on what was most recently worked on, not something that probably still has factory torqued fasteners, right?

    P0ADC = Hybrid Battery positive contactor control circuit high
    P0AE7 = Hybrid Battery precharge contactor control circuit high

    Pull the small cover off the battery and check everything, especially the medium sized plug going from the car harness to the HV battery. That's the connector that supplies power for relay/contactor operation. May even be a broken wire in that small harness in the HV battery relay area..
     
    #3 TMR-JWAP, Apr 17, 2020
    Last edited: Apr 17, 2020
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  4. Bilewis1994

    Bilewis1994 New Member

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    Thanks I started using Dr Prius to analyze codes but don't think I can get sub codes from it. Can you recommend a app or analyzer to help with that? It was stupid to replace the inverter. It was a more a shot in the dark.
     
    #4 Bilewis1994, Apr 17, 2020
    SFO likes this.
  5. Bilewis1994

    Bilewis1994 New Member

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    I found my issue. So here goes! Inside the Hybrid Assy next to the controller Module,
    there is a wiring harness with 3 green wires that has a nut holding it in place or to ground. Oh yes the nut was loose.
    Not only loose but ready to fall off. These ground wirers are attached to the relays. Word to the wise, when repairing a hybrid battery assembly. Take out your 8, 10, 12mm sockets and torque every nut and bolt down. I literally got more than 10 error codes that confused the crap out of me. And I apologize for wasting everyones time who read this feed. I should have found this in minutes not days.
     
    #5 Bilewis1994, Apr 21, 2020
    txducker, PriusCamper and SFO like this.
  6. TMR-JWAP

    TMR-JWAP Senior Member

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    Glad you found it and everything worked out. Don't feel bad, every single person on the forum who builds batteries was a rookie when they started. We've all had "learning opportunities".
     
    #6 TMR-JWAP, Apr 21, 2020
  7. SFO

    SFO Senior Member

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    For sub codes, many choose to use a 'Mini-vci' cable with Techstream (dealership technician software) installed on a windows device.
     
    #7 SFO, Feb 8, 2021
  8. dolj

    dolj Senior Member

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    @PriusCamper has said that Dr. Prius can get sub-codes. Maybe he can help here.
     
    #8 dolj, Feb 8, 2021
  9. PriusCamper

    PriusCamper Senior Member

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    Yep... We all learn the hard way the need for both redundancy (double & triple check everything) as well as the need for assembling everything in the proper sequence... For example that loose bolt of yours is hard to notice once you're done. But if the first thing you bolt down and double/triple check before you bolt down everything it's attached to...
     
    #9 PriusCamper, Feb 8, 2021
  10. Monkey-like

    Monkey-like New Member

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    Appreciate the post but this part just comes across as downright dangerous. Just advising people to torque every nut and bolt down on their hybrid assembly isn't wise at all. Especially that ground connection with the green wires. That would be a surefire way to fry yourself if you haven't taken the right precautions.

    Sorry for the necro but I just got the p0a94 issue and saw this.
     
    #10 Monkey-like, Dec 6, 2023
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