Dashboard lights and error codes P0AC0, P0B47

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by blueshades, Aug 25, 2020.

  1. blueshades

    blueshades Junior Member

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    Hi all,

    I have a 2011 Prius. When I start the car, the Check Hybrid System, Check Engine, and Master Warning lights are on. A few seconds later when the combustion engine is running, the Brake System Warning light and Slip Indicator are on. The car is in ready mode and I can drive it. The error codes are P0AC0 and P0B47.There are 2 codes of P0AC0, P0AC0-123 and P0AC0-817. I am not sure which one it refers to. I use Dr. Prius and check the battery. At the beginning, there is no green bar in block number 1. Then it shows no green bars in block numbers 1 and 7 and block number 8 turns red.

    I have looked at the information on the Internet, does the battery voltage sensor turn bad? Do I need to replace any battery?

    20200825_201200.jpg Screenshot_20200825-191652_Dr Prius.jpg Screenshot_20200825-191708_Dr Prius.jpg
     
    #1 blueshades, Aug 25, 2020
  2. bisco

    bisco cookie crumbler

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    start with a load test of the 12v. how many miles on her?
     
    #2 bisco, Aug 26, 2020
  3. blueshades

    blueshades Junior Member

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    Thank you for replying!
    The car has 122076 miles on it. I live in Houston, so I think the warranty on the hybrid battery expires. I wanted to see if Toyota can extend the warranty to 10 years/150000 miles.
    The car hasn't been driven for 1 day and the voltmeter reads 12.4. The voltage test in the car shows
    idle mode: 11.4V
    load mode with AC on: 10.7V
    ready mode: 13.5V.

    There is 1V difference between the voltmeter and the idle mode from the car. The 12V battery is a Duralast battery installed in Apr 2019. It did die once in Jan 2020.

    I went to the Toyota dealership few days ago. They said the 12V looked new and they wanted to charge $470 for the diagnosis on the hybrid battery. I did not proceed. I thought about changing the 12V battery. My concern is if it was not the 12V battery problem, I would waste a battery.
     
    #3 blueshades, Aug 26, 2020
    Last edited: Aug 26, 2020
  4. Grit

    Grit Senior Member

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    Why stop at 10 years 150K, make it lifetime warranty. Toyota won’t even acknowledge the EGR issue, and then ask them to extend a warranty? :whistle:
     
    #4 Grit, Aug 27, 2020
  5. davecook89t

    davecook89t Senior Member

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    You may not need to replace the HV battery, but either you or someone else will need to open up its case and check for corrosion on the sensor wires, bus bars and possibly the ECU. Hopefully, they can all be cleaned with a solution of baking soda and water, but you or your mechanic would need to disassemble some of those parts.

    The charge on your 12V is probably adequate for reporting the correct error codes on the HV battery and its components.
     
    #5 davecook89t, Aug 27, 2020
  6. blueshades

    blueshades Junior Member

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    I open part of the hybrid battery and take the battery voltage sensor out. I have not tested the battery yet. It seems that there are corrosion on two pins and one pin goes dark at the bottom. The part number of mine is 89892-47020. Toyota has a newer model (89892-47080) which replaces 89892-47020. I am planning to order a used one. Which one should I go for?
     

    Attached Files:

    #6 blueshades, Aug 28, 2020
  7. davecook89t

    davecook89t Senior Member

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    Hopefully, a Gen 3 owner, @ChapmanF, can answer that question.
     
    #7 davecook89t, Aug 29, 2020
  8. ChapmanF

    ChapmanF Senior Member

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    I may know many things, but battery ECU part number details are not among them. Haven't needed those so far.
     
    #8 ChapmanF, Aug 29, 2020
  9. ASRDogman

    ASRDogman Senior Member

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    Maybe you don't need to replace it. Just clean the contacts, then try it and see if you get the same error.

     
    #9 ASRDogman, Aug 29, 2020
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  10. ChapmanF

    ChapmanF Senior Member

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    Have you looked in the repair manual yet (more info) for the meanings of the codes? "information on the Internet" can be ... all over the map.

    My 2010 manual lists only the variant with INF code 123 (they could have added a second INF code in a later year). For INF 123, the detection condition involves the battery current sensor (not the voltage sensor, so you may have been barking up the wrong tree there). The current sensor will look like a small donut that one of the heavy battery wires will pass through.

    P0B47 does refer to a voltage sensor, specifically for block C. The detection condition is a voltage below 2.5 volts, so it isn't a "hey, your block is weak" code, it's a "hey, bad wire or terminal" code.
     
    #10 ChapmanF, Aug 29, 2020
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  11. blueshades

    blueshades Junior Member

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    I bought a used battery voltage sensor (89892-47080) to replace the one (89892-47020) in my car. The two permanent code (P0AC0, P0B47) did not show up anymore.

    I am going to clean the fan and remove the corrosion on the copper since I have opened the battery.
     
    #11 blueshades, Sep 4, 2020
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