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Replacing Control ECU

Discussion in 'Gen 2 Prius Technical Discussion' started by Market05, Mar 17, 2017.

  1. Market05

    Market05 New Member

    Joined:
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    Location:
    Western Maryland
    Vehicle:
    2005 Prius
    Model:
    II
    I have installed 3 different transaxles and was getting code P0A90, when I read that this code could be caused by a bad Control ECU. I got one off of the internet and installed, but now I'm finding that it doesn't work. I think it needs to have the key code registered. Not sure I've turned it on and off 20 times yet (I read if I turn it on and off 20 times it will go bad and I'll need another one), but I really need to find out fast what I need to do this before I spend another minute trying! Please help! Can I use a laptop with a specific software? I'm sure the dealer can do it, but don't want to spend the money to tow it anywhere. I also don't want to spend money at the dealers!
     
    #1 Market05, Mar 17, 2017
  2. ChapmanF

    ChapmanF Senior Member

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    Vehicle:
    2010 Prius
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    IV
    Holy smokes, did you ever spend the $15 to access the repair manual, before putting in 3 transaxles and an ECU?
     
    #2 ChapmanF, Mar 17, 2017
  3. Market05

    Market05 New Member

    Joined:
    Feb 27, 2017
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    Location:
    Western Maryland
    Vehicle:
    2005 Prius
    Model:
    II
    I bought the Haynes, which I'm finding out is lacking. Actually I first paid someone to install the Trans. When I got the code a week later I decided to pull it and take it back on warrantee myself. The first time the code was thrown was with the original.
     
    #3 Market05, Mar 17, 2017
  4. ChapmanF

    ChapmanF Senior Member

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    2010 Prius
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    IV
    The $15 is a really good investment before jumping into parts swapping, because when you look up the code there, it will send you straight to a troubleshooting section with from one to several pages of systematic steps to follow to find out what the trouble is, before you get the wrenches out to fix it.

    -Chap
     
    #4 ChapmanF, Mar 17, 2017
    Raytheeagle likes this.
  5. Market05

    Market05 New Member

    Joined:
    Feb 27, 2017
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    Location:
    Western Maryland
    Vehicle:
    2005 Prius
    Model:
    II
    Got the ECU programmed today. Everything started great, and the first trial run of 40 miles went without any issues. Hope I've solved the issue, but guess we will find out.
     
    #5 Market05, Mar 19, 2017
    05PreeUs likes this.
  6. Market05

    Market05 New Member

    Joined:
    Feb 27, 2017
    27
    7
    0
    Location:
    Western Maryland
    Vehicle:
    2005 Prius
    Model:
    II
    Made it to work today without any trouble codes or hesitation in the unit. Crossing my fingers... I will feel more comfortable if it gives me a week of trouble free use, and then we'll see from there!
     
    #6 Market05, Mar 20, 2017
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