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2005 Prius with a lot of ODB codes

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by rsmithx, Jun 30, 2019.

  1. rsmithx

    rsmithx New Member

    Joined:
    Jun 30, 2019
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    Location:
    Shelton, WA
    Vehicle:
    2005 Prius
    Model:
    Four
    So my master warning light came on as well as my traction stability light and brake system warning light.

    After troubleshooting I reset the ECU by disconnecting the 12 volt battery for about 5 minutes. Turned the car back on and none of the warning lights persisted.

    Took the car for a 15 minute drive, everything seemed fine, stopped at the auto parts store to pick up some oil, got groceries and driving out of the grocery store the dashboard once again lit up. I was about 1/4 mile from the auto parts store so drove over there and immediately had the codes read.

    These are the codes that popped up:
    p0a80 p3000 c1241 u0073 u0123 u0124 u0126

    The first two codes from what I have read seem to indicate that there is a problem with the HV battery system, the c1241 is a high/low voltage alert. Then the rest of the u codes (from what I can gather) indicate that there is a problem with the canbus network.

    The car is currently parked at the auto parts store (wife picked me up) while I try to figure out how to proceed. My guess is I need to take it to a hybrid mechanic but not even sure if I should be driving it.

    Just looking for any guidance anyone might have on narrowing down what could be wrong and how to proceed.

    Thanks for any advice.
     
  2. rsmithx

    rsmithx New Member

    Joined:
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    Location:
    Shelton, WA
    Vehicle:
    2005 Prius
    Model:
    Four
    I have watched several video's and feel (mostly) confident that I can swap out the HV batteries, I think what I am nervous about is replacing the whole battery system if that isn't the actual problem.

    Car has 252K miles (so in the range of batteries dying). But I have had problems that I thought were the HV battery only to find out I just needed to replace the 12V battery and everything was fine. Just so unsure of how to troubleshoot this car. :/
     
  3. exstudent

    exstudent Senior Member

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    Location:
    Torrance, CA
    Vehicle:
    2007 Prius
    14y/o car, 252k miles, P0A80 ... the HV Battery needs to be replaced. Assuming it is the original pack that came w/ the car, it has had an excellent run!

    You just need to decide what your short/long term plans are w/ the car, and how much you are willing to spend or not spend.
    Do I need a reliable vehicle for my personal lifestyle and employment?
    Is there anything else I would rather do w/ my time than working on the HV Battery (repeatedly if I do module swaps)?
    How much longer do I want to keep the car?

    Swapping out modules is a band-aid repair. Can last hours/days/weeks/months.
    Used (rebuilt/reconditioned/remanufactured) from GreenCrappyBean ($1549) and other's are a poor choice.
    Rebuilders are a dime a dozen. Quality of their work is all over the place: few good rebuilders, many hacks.
    Best long term, trouble free, repair is to replace w/ NEW OEM HV Battery ($1600+) or 2k1Toaster's cylindrical modules ($1600).​


    Member @PriusCamper and @Jmack111 are big proponents of repairs; maybe they will chime in and can offer their services to you (both in metropolitan areas of WA). I'm on the other extreme of get a new OEM HV Battery: I want a reliable and trouble free car, avoid unnecessary repairs, and can afford a new OEM HV Battery.

    The right tools make a world of difference: Techstream + the factory service manual are the best bet!

    Techstream is the OFFICIAL diagnostic and maintenance software, written for Toyota/Lexus, and used at all Toyota/Lexus dealerships. Techstream or other EXPENSIVE professional commercial code readers are able to read ALL CODES and perform maintenance procedures. Toy bluetooth OBD2 readers can NOT read all codes and can NOT do any maintenance.

    Download a copy of the official Toyota service/repair manuals (engine, mechanical, interior, exterior, electrical, essentially EVERYTHING), go to TIS Two days will cost you $20. Supposedly only business days are counted (remember reading this in other threads). If you start on a Friday 12:00:00 AM, you have until Monday 11:59:59 PM, to finish.

    This user downloaded both his Toyota cars over the course of his 2 business day subscription. Toyota TIS download tips | PriusChat

    P0A80 = replace HV battery
    P3000 = HV battery ECU(s) problem; Techstream would provide sub-codes and allow you to test the ECU(s). Factory manual provides trouble shooting steps.
    C1231 = essentially low 12V bus due to low 12V batt
    The Ucodes could be legitimate or likely due to the low 12V battery. Recharge the 12V battery w/ an AGM compatible battery charger or replace the 12V w/ a fully charged AGM battery. If the Ucodes come back, then the initial Ucodes were legitimate. Factory manual provides trouble shooting steps for these Ucodes. Techstream will also provide the subcodes too!
     
    #3 exstudent, Jul 1, 2019
    Last edited: Jul 1, 2019
    jerrymildred likes this.
  4. jerrymildred

    jerrymildred Senior Member

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    Location:
    Tampa, FL
    Vehicle:
    2017 Prius
    Model:
    Two
    I agree with @exstudent. But with a C1231, I'd start by making sure the 12v battery is up to snuff. Go for the low hanging fruit first. If that's good, then head on down the HV battery path. I also share his distaste for rebuilding HV batteries. I'd do it if it was the only thing I could afford, but it's not my first choice. And I like to tinker. ;)
     
  5. Skibob

    Skibob Senior Member

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    Location:
    Northern California
    Vehicle:
    2006 Prius
    Model:
    N/A
    252,000 miles. How is the rest of the car? How much oil does it burn? How many times have you run it out of oil/ seen the low oil pressure light? Rebuilding your battery might be a better option for you based on how you answer these questions.
     
  6. strawbrad

    strawbrad http://minnesotahybridbatteries.com

    Joined:
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    Location:
    Minnesota
    Vehicle:
    2005 Prius
    Model:
    II

    A P0A80 codes does not always mean the HV battery has died.o_O

    There are lots of conditions that will run down a perfectly good battery until it throws a P0A80 codes. A partial list includes running out of gas, dirty MAF sensor, bad VVT, bad spark plugs, engine simply running poorly, and in this case four U codes that all relate to the ABS/Skid Control Computer.

    I have seen that group of U codes make a car act like it was possessed including running the HV battery down.

    To proceed with repairs you'll really need Techstream. You could go cheap with a Mini VCI cable but I recommend spending a little more money on a VXDIAG cable. Once you have the cable and Teachstream setup learn how to run a forced charge and discharge while watching live battery data. In a failed battery one module block will have the highest voltage on charge and the lowest voltage charge on discharge. To trip a code the difference between module blocks has to be over 1.2 volts.

    If you don't see an obvious failed cell with a forced charge and discharge it's time to replace the Skid Control Computer. You'll need Techstream to install a new Skid Control Computer.
     
    Skibob and jerrymildred like this.