Battery Replacement - Low voltage error - P0AFA, P3000

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by cammo789, Jan 9, 2022.

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  1. cammo789

    cammo789 Junior Member

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    Aloha - I was about to post the below but now I’m not sure.

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    Original post and findings:

    Doing a 2008 Prius battery replacement using newpriusbatteries

    I am getting P3000 and P0AFA errors. I found that these are low voltage and vague errors indicating the system can’t see the battery. The Dr. Prius voltage results seem to confirm that.

    I then checked with the multimeter on each cell and as a unit and confirmed there is ~200V for the entire battery, so the individual cells seem okay. This led me to think one of the pins in the ECU/housing or connectors was corroded/bad/missing. I think I found that that is the case and just wanted to double check with all the smart folks here.

    I think the largest of the 3 connectors have at least 2 of the larger pins missing. See pics. The other two smaller connectors seem okay, but it’s hard to see.
    (update: After reviewing this, the internal metal connector inserts are missing in certain holes because there are no wires going into them from the other side in the first place. Disregard?)

    Apologies if my terminology for the individual components is wrong.
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    Anyway, now I’m not sure where the issue might be. I’m fairly certain the cells themselves are fine, but suspect something is tripping the system into not recognizing the battery. The 12V battery seems to be working fine too. I’ve also cleared the codes using the Dr. Prius app.

    IMG_4783.jpeg IMG_4769.png IMG_4795.jpeg IMG_4791.jpeg IMG_4787.jpeg IMG_4786.jpeg IMG_4785.jpeg IMG_4759.jpeg IMG_4758.jpeg IMG_4757.jpeg IMG_4755.jpeg IMG_4752.jpeg IMG_4753.jpeg IMG_4750.jpeg IMG_4749.jpeg IMG_4768.png
     
    #1 cammo789, Jan 9, 2022
  2. SFO

    SFO Senior Member

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    Welcome to PriusChat!!
    Have you already secured (grounded) the metal HV battery case to the vehicle by using the larger case bolts? (can't tell from the pictures)

    FYI : you're moderated until you've posted 5 times.
     
    #2 SFO, Jan 10, 2022
  3. cammo789

    cammo789 Junior Member

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    Thank you!

    Believe I have. I put just the large cover and ECU cover over it. The large cover has most of the case bolts fastened at this point.

    Does the entire case housing need to be secured for it to be grounded? I followed the video from electron automotive and they were testing with just those two pieces on it.
     
    #3 cammo789, Jan 10, 2022
  4. SFO

    SFO Senior Member

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    Yes. You can try a single bolt, but you might as well secure all of them.
     
    #4 SFO, Jan 11, 2022
    2k1Toaster likes this.
  5. cammo789

    cammo789 Junior Member

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    Ok - Secured the full HV battery case to vehicle - no change.

    Also forgot to unplug 12V battery so that was drained - replaced it today. Good times.

    More pics showing the 200V and various ECU connections.

    IMG_4825.jpeg IMG_4826.jpeg IMG_4827.jpeg IMG_4828.jpeg IMG_4829.jpeg IMG_4830.jpeg IMG_4842.jpeg IMG_4843.jpeg IMG_4844.jpeg
     
    #5 cammo789, Jan 17, 2022
    Last edited: Jan 17, 2022
  6. SFO

    SFO Senior Member

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    #6 SFO, Jan 18, 2022
  7. Frank1234

    Frank1234 Member

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    Try this it may fix you problem, check the plug next to the hybrid battery fan, in my case I haven’t have the code again, look a the pictures.
     

    Attached Files:

    #7 Frank1234, Jan 18, 2022
  8. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    Something like this is usually wiring/connector related. You can measure the battery and it's fine but the computer in the car isn't reading the same thing. The question is why. It could be the physical connection and wiring all the way to the computer (ECU) itself. The ECUs in these cars do go bad sometimes and that can involve weird readings.

    It can also be strange things caused by a bad 12v battery. During the HV Battery install the hatch is opened a long time. Most people do not disconnect the 12v battery because it's too much work. This causes a drain on that little aged battery for hours and can kill it.

    First step is checking the safety disconnect plug, especially the contacts underneath it. That's a pain in the butt.

    Next would be to measure the voltage at the module and then the voltage at the end of the harness. They should be mostly equal, obviously less on the harness after resistance.
     
    #8 2k1Toaster, Jan 26, 2022
  9. cammo789

    cammo789 Junior Member

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    Alright, looks like it's working now! I think I narrowed it down to either the safety plug, re-connecting this connector (see attached img), and/or the 2 nuts on the main section of the case being attached (to help ground battery). The wiring harness connector seemed loose. I just went with the mantra "try, try again", per @2k1Toaster

    Thank you all for your help.

    One more question - I'm about halfway through putting everything together and notice I forgot to put on the black safety covers that go over each cell. Are these for safety/cable mgmt/rust protection/etc.? I'm guessing they are highly recommended, but how recommended? lol
    I plan to (begrudgingly) open it up again and put them on, I just don't entirely know their function.

    Thanks again!!
     

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    #9 cammo789, Jan 31, 2022
  10. cammo789

    cammo789 Junior Member

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    #10 cammo789, Feb 1, 2022
    Last edited: Feb 1, 2022
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