After HV battery rebuild, no codes, will not go into D

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by LKasdorf, Mar 26, 2020.

  1. LKasdorf

    LKasdorf Junior Member

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    2005 prius 140k. Threw a red triangle, I determined bank 5 was low. I got a used good blade, charged it on the bench to match voltage of the other blades, and installed. I cleared codes and all was well.

    I drove the car down the road while monitoring the HV battery in Dr Prius. About a mile away, there was a klunk, and the Red Triangle came back. The car was very sluggish and wouldn't go over 35. The energy display showed that there was no interaction with the battery at all- it was strictly running off the engine.

    I read the codes and I had a P0AA4 - saying a contactor was stuck closed. I tried tapping them with a nylon hammer to no avail. I pulled the HV fuse and disconnected output wires from the contactors and checked continuity on the contactor terminals. They were both open as they should be. I put it back together and put the cover on over the contactors to make sure the metal rings around the output cables were firmly grounded, in case that matters.

    I pulled the 12v battery neg terminal to let everything clear. I just had the HV battery sitting there not bolted down for my initial test. I bolted it down in a couple places, in case the case ground was important.

    After a long wait, I reconnected the 12v battery. Using Dr Prius, I cleared all codes. The triangle went away, and no battery or engine codes are reported, either in torque or dr prius.

    BUT- it will not go into D or R. Just P and N. And I have the following lights: brake, CEL, Maint Req, ((!)), ABS, car skidding

    At one point, I did try it with the HV fuse out (by accident). I got battery codes P0AA4, P0A0D, P0AA1

    I also checked fuses and they all seem good. The 12v battery reads 12.2v. That strikes me as a bit on the low side. I'll hang a charger on it tonight.

    I did replace a battery blade a few months ago, and I recall I had some shenanigans kinda like this before it started working, but it eventually did.
     
    #1 LKasdorf, Mar 26, 2020
    Last edited: Mar 26, 2020
  2. bisco

    bisco cookie crumbler

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    did you replace the orange safety plug correctly?
     
  3. LKasdorf

    LKasdorf Junior Member

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    Yes- it is back correctly, and I verified that I get something like 235v at the output of the battery before the contactors.
     
  4. LKasdorf

    LKasdorf Junior Member

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    Ok- I was able to get out of this weird state by "rebooting" - power off, hold start button for 45 seconds, foot on brake & start button. Doing this brought it back to normal...
    BUT on a test drive, it very quickly threw a P0A7A (Generator Inverter Performance).
    I reset this, drove further, and I quickly get P0A94. This happens over and over.
    I took out all 3 relays and bench tested- all good.
    Now, I sometimes get a P0AA4 which is negative contactor circuit problem. I guess the next test is to see if I get 12v on the contactor coils when the car is on.
    I need to get techstream happening- I'm doing all this with torque and dr prius and a blueooth ODBII and it is a real PITA to get it to connect reliably.
     
  5. George W

    George W Active Member

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    You are correct that the 12-volt battery is on the low side, and low 12 volt can cause all kinds of odd errors. How old is it?
     
  6. LKasdorf

    LKasdorf Junior Member

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    do not know how old the battery is. It was in the car when we got it 9 mo ago. It is a nice Ac Delco AGM, so it had been replaced at some point by prev owner.
    I hung a charger on it last night and this morning it showed 12.8, so I think that is OK.
    Right now I'm trying to get an old XP or win 7 laptop running so I can easily set up techstream. I have a VCI cable.
     
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