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P0A1F HELP!!! cant find the issue

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by engarom, Feb 25, 2018.

  1. engarom

    engarom New Member

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    I have a 2006 Prius - P0A1F DTC. I know its supposed to be a Battery ECU issue. But,... I have thrown two ECU at it, same issue. And I now have a completely different battery and ECU in the car, same issue.
    Dash has the following lights on, Triangle, check engine, and (!) .
    I really need some help here. It runs and drives, but maybe a little less power than normal.

    Anyone else seen this?
     
    #1 engarom, Feb 25, 2018
  2. Raytheeagle

    Raytheeagle Senior Member

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    Welcome to Prius Chat (y).

    Some questions:

    • What code reader are you using to pull the codes?
    • Was there any recent maintenance performed just prior to te issued you are experiencing?
    • If you replaced some parts and the issue is still there with replacement parts, what was your next step going to be?
    • We’re you replacing the parts yourself, or is a mechanic assisting?
    Keep us posted(y).
     
    #2 Raytheeagle, Feb 25, 2018
  3. engarom

    engarom New Member

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    Techstream screen 2.jpg Techstream screen 3.jpg Techstream screen 4.jpg Techstream screen.jpg Update - here is the complete code = P0A1F-593
     
    #3 engarom, Feb 25, 2018
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  4. engarom

    engarom New Member

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    To answer the questions above;
    I used Techstream software
    I didn't do anything. the car came to me with these issues. Previous owner doesn't know anything.
    I guess my next step will be getting a new harness and replacing it. I tried testing the harness and connector but had mixed results.
    I was testing continuity at the HEV fuse and it seems like the post are switched. The service guide indicates I should check continuity between the number 2 post of the HEV fuse and the number 1 wire (AM) on the B11 plug at the Battery ECU. For some reason, I dont get anything on post 2, but post 1 shows continuity. I thought maybe I was checking the wrong post but i check it multiple times and it is always on post 1 instead of 2. Weird, maybe the toyota documentation is wrong? I cant see how that could be
     
    #4 engarom, Feb 26, 2018
  5. exstudent

    exstudent Senior Member

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    Strange.

    Did you disconnect the 12V ground for a minute or two, then reconnect, and clear all codes?

    Are you using the factory manual for your 2006? If you are using a different model year, it is possible the manufacture could have changed something.
     
    #5 exstudent, Feb 26, 2018
  6. engarom

    engarom New Member

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    Yep, disconnected the ground.
    and all my tech manuals are for gen 2 prius.
    im using one I found online. it seem legit, its called "p112 hybrid vehicle control"
     
    #6 engarom, Feb 26, 2018
  7. exstudent

    exstudent Senior Member

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    Seems legit, does not mean it is legit, esp since you don't have the GENUINE, 2006 Toyota service manual to reference. You hope what you have is legit.

    A two business day subscription to TIS is only $15.
    Toyota - New Subscription

    You can follow this guy and convert the CHM file to a PDF. You will now have a GEUNIE, AUTHENTIC, 2006 Toyota Prius service manual.
    Toyota TIS download tips | PriusChat
     
    #7 exstudent, Feb 26, 2018
  8. edthefox5

    edthefox5 Senior Member

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    Your 12 volt battery is toast.

    And harness has corrosion going up the leads under insulation.
     
    #8 edthefox5, Feb 26, 2018
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  9. engarom

    engarom New Member

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    I suspected the 12v battery, looked like it was still the original, so I replaced with a yellow top optima.
    As for corrosion in the harness wires, how do I even begin to diagnose this or know which harness to replace?
     
    #9 engarom, Feb 26, 2018
  10. edthefox5

    edthefox5 Senior Member

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    To be honest just spit balling but corrosion is a really big factor in retro fit. Look at all the original connector ends including plugs for even the slightest corrosion/green. if you see any pull back the rubber insulation and see if its travailing up the wire. It will rot the wire up or at the least present resistance. Ohm out connections if you can. Good place to start.
     
    #10 edthefox5, Feb 26, 2018
  11. engarom

    engarom New Member

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    Ok. I understand. I started looking for corrosion at the ECU connector and so far everything looks good. I will spend some time checking as many connections as possible, maybe I will come across the issue. Last thing I will do is see if I can find a harness to swap out.
     
    #11 engarom, Feb 26, 2018
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    DTC P01AF-593 means that the battery ECU thinks the IG2 voltage is low. On the B11 plug, the following pins should have 12VDC: pin 1 which is marked AM, pin 2 which is marked IGCT, and pin 13 which is marked IG2.

    If you can measure continuity between one side of the HEV fuse and the AM terminal, then that wire should be considered good. It could be that the documentation confused post 1 and post 2.

    Also, try to measure continuity between one side of the IGN fuse and the pin 13, IG2 terminal at the B11 plug.

    Make sure that the 12V battery is in excellent condition. Whenever you have an ECU reporting low battery voltage, it is reasonable to make sure that the battery is fully-charged.

    I understand you've already swapped the battery ECU, so it could be a problem with the 12V battery or the wiring.
     
    #12 Patrick Wong, Feb 27, 2018
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  13. engarom

    engarom New Member

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    I have a few things to check to keep me busy. I am confident I will get it sorted out. just a few more wires to check!
    I will make sure to update you all as soon as I get to the bottom of this.
     
    #13 engarom, Feb 28, 2018
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