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I'm getting a P3030 and a P0AC0 ... might 12V battery be to blame?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by blueprius2006, Jul 11, 2023.

  1. blueprius2006

    blueprius2006 Junior Member

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    I am getting codes P3030 and a P0ACO. I checked my 12V battery and in a parked state, it is showing a reading of 11.8V. Might the battery be to blame for this? Any suggestions? Picture below. Thank you.
     

    Attached Files:

    #1 blueprius2006, Jul 11, 2023
  2. bisco

    bisco cookie crumbler

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    it's a small possibility. charge it up and see if it holds. if not, replace it.
     
    #2 bisco, Jul 11, 2023
  3. bisco

    bisco cookie crumbler

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    #3 bisco, Jul 11, 2023
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  4. PriusCamper

    PriusCamper Senior Member

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    There's a chance it could be something other than a 12v, but until the 12v is fully charged or replaced, there's no way to find out.
     
    #4 PriusCamper, Jul 11, 2023
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  5. Brian1954

    Brian1954 Active Member

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    No, the 12v battery probably will not cause those two trouble codes. The HV battery can cause those codes.

    Posted via the PriusChat mobile app.
     
    #5 Brian1954, Jul 11, 2023
    Last edited: Jul 11, 2023
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  6. sam spade 2

    sam spade 2 Senior Member

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    Sorry. Wrong answer.
    The right answer is in post #4 above.

    A no load reading of 11.8 indicates that the battery has a charge of LESS than 15% and that can
    cause all kinds of problems.
     
    #6 sam spade 2, Jul 12, 2023
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  7. dolj

    dolj Senior Member

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    While it definitely is advisable to follow the advice in post #4, the 11.8 V shown in the opening post is not a "no load" reading. To get that reading on the MFD, the OP has to have had the car in IG-ON. Unless the battery drops further to 9.5 V (or in some cases below 10.5 V) on startup, it definitely will not "cause all kinds of problems."

    I can tell you from experience in a Gen 2 it is not uncommon for the 12 V to drop to 11.8 V on startup and I can assure all readers that it causes no ill effect.

    So unless contributors have solid evidence to support their claims, let's dispense with the bad information.
     
    #7 dolj, Jul 12, 2023
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  8. Brian1954

    Brian1954 Active Member

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    Codes P3030 and P0AC0 are triggered when the car is in "READY". When the car is in "READY" the inverter is supplying 13+v to the car. The 12v battery is being charged from the inverter at that point, so a 11.8v in the battery has no effect in triggering the two trouble codes.

    The two trouble codes are being triggered by a problem with the HV battery.

    Posted via the PriusChat mobile app.
     
    #8 Brian1954, Jul 12, 2023
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  9. sam spade 2

    sam spade 2 Senior Member

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    Sorry I'm not perfect like you.
    I didn't look at the image in the post.

    And flatly stating without any qualifications that the 12 V battery can NOT cause that to happen is no more right
    than what I said.

    Lighten up a bit, please.
     
    #9 sam spade 2, Jul 12, 2023
  10. Brian1954

    Brian1954 Active Member

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    You misquoted what I wrote, which was
    "PROBABLY WILL NOT CAUSE"

    Now I will lighten up.
     
    #10 Brian1954, Jul 12, 2023
    Last edited: Jul 12, 2023
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  11. dolj

    dolj Senior Member

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    Yeah, no worries.
    I guess years of data collection and observation from actually driving this model doesn't count for anything.

    It would seem you have basic reading comprehension problems if you can't see the qualifications attached to my statement. Troll elsewhere.
     
    #11 dolj, Jul 12, 2023
  12. SFO

    SFO Senior Member

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    Do you need any help finding the diagnostic workups for the above DTCs?
     
    #12 SFO, Jul 13, 2023
  13. blueprius2006

    blueprius2006 Junior Member

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    Do you mean descriptions of the error code? No, I was able to look them up...
    **

    update: It seems that it is not an issue with the 12V battery. An AAA tech came to look at the 12V He said the battery is fine but the hybrid system is not charging it properly.

    I was able to charge it up I believe by driving around and taking it on the highway for a bit (I'm rather wary of doing so given the state the car is in). Here are some update images below


    WhatsApp Image 2023-07-13 at 13.21.49.jpeg WhatsApp Image 2023-07-13 at 13.23.42.jpeg
     
    #13 blueprius2006, Jul 13, 2023
  14. bisco

    bisco cookie crumbler

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    so now you have to address the codes
     
    #14 bisco, Jul 13, 2023
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  15. SFO

    SFO Senior Member

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    Since there may be confusion, I will post the workups for whoever may need them. Page 66 of 165 (or HB 66) has the workup for DTC P0AC0 (and P0AC1 P0AC2 P0ABF): https://attachments.priuschat.com/attachment-files/2020/03/183963_Hybrid_Battery.pdf

    Here is the workup for DTC P3030 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/20zmw/cip3030b.pdf

    As Bisco kindly mentioned in post #3 above, DTC P3030 may be an issue with the high voltage sense harness tabs / connector or the HV battery ECU socket / PC board. Does the interior of the vehicle have any condensation or standing water?

    An example of what damage at ECU and harness plug can look like :

    [​IMG] [​IMG]

    Notice how pins 22 & 23 (bottom right) on the ECU socket have broken off and are stuck inside the plug on the right.
     
    #15 SFO, Jul 13, 2023
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  16. blueprius2006

    blueprius2006 Junior Member

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    Hi... yes, the harness is damaged. I was told the ECU was also burned out and needed to be replaced. Here is a picture the mechanic sent me. He said some of the pins are corroded.

    cfec1dec11cfe1e94f5aa6be30df0b5d6e6f8cb3-1.jpeg
     
    #16 blueprius2006, Jul 13, 2023
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