2012 Prius C2 No dash lights and doesn't start. Any help would be greatly appreciated

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by Brooklyn_Boy, Oct 11, 2020.

  1. Brooklyn_Boy

    Brooklyn_Boy New Member

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    St. Johns, Fl
    Vehicle:
    2012 Prius c
    Model:
    Two
    Rob.
    Thanks so much for your further input and embedded YouTube videos. I did see the second of the videos as you did but not the first.
    They both hold valuable information but for me, especially the first because it clearly shows the location of the battery sensor on the 12V battery side of the hv battery. It appears that I can replace the battery sensory without taking the hv battery out which I anticipate to be my first action in an attempt to repair the car.
    The dealer identified 2 dtc codes : P0B42 - Hybrid battery voltage sensor B Circuit is low and P0B47 - Hybrid battery voltage sensor C Circuit is low, as well as the technician's notes, none of which specifically identify the need for replacing the hv battery.
    We did speak with him about the warranty situation - 8 years and/or 100k miles. At the time we had the car towed to the dealership it had somewhere betweeen 55k-60k miles and 8 years/6 months time on the warranty. We asked about the possibility of some consideration based upon the mileage but nope. And then he hit us with the Toyota National Warranty on new HV Batteries being 1 year. Frankly it reminded me of being drafted and going down to the induction center for my armed services physical.
    Regardless, thanks again Rob. As soon as my wife lets me know that I decided to purchase the battery sensor and replace the current one I will move forward with doing so.
     
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  2. Brooklyn_Boy

    Brooklyn_Boy New Member

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    Vehicle:
    2012 Prius c
    Model:
    Two
    Good evening all and early best wishes for everyone for their identified holiday season.
    Since my last update my supervisor (read: wife) advised me that it was my idea to go ahead and change the battery voltage sensor located off the hv battery. I started about 2 pm this afternoon and with my son's assistance completed part I (removing all necessary parts up to the old battery sensor) and we will essentially place the new sensor and put everything back together tomorrow.

    I didn't remember to start taking pictures from the beginning but I think soon enough to give others an idea of what it was like to replace the battery voltage senor that is bolted onto the hv battery. At some point I will attach the pages from the Toyota Repair Manual for the Prius C2 2012 to share.
    I purchased the battery voltage sensor online from a dealership that allowed a 90 day return. The cost with shipping was a little over $230.00, less that the $330 that my dealership quoted. It took about a week to arrive at the house.
    I started by opening the hatch and removing the hatch carpet, the underlying carpet, as well as the left and right styrofoam spare tire coverings. I then removed the clips from the (3) front covers of the back seat. I then removed the 12v battery and put it on a trickle charger that we had.
    At that point we lifted the back seat, pulled it up past the seat belts and then pulled it up and off the two retaining clips to the subframe. The subframe is secured by four bolts and once removed you get a clear view of the battery vent (on the passenger's side) and the orange safety plug. We then pulled the safety plug and waited 10 minutes. We removed the black vent and the rear retention bracket to the 12v and had a clear view of the side of the battery. Once you see the white connector the battery voltage sensor is behind the metal case. Internally you will find a connection to an orange harness and an connection to a black clip.
    You have to remove the side of the case to get to the battery voltage sensor. The side of the battery is retained by four bolts and the sensor held in place by two others.
    I then removed the old battery sensor and was careful about removing the 3 connectors. I found it interesting that at this point the internal components of the battery were clearly visible and removing the entire battery could have been removed with the removal of the cooling fan and whatever number of bolts attached the battery housing to the floorboard of the Prius C.
    During the diagnostic testing we were told that there was corrosion on the voltage sensor and the harness. There was some rust on the body of the unit but there was no real evidence of corrosion. We also took a picture of the orange harness (battery), again we were told that there was corrosion. The picture we took doesn't really show any corrosion but we'll clean out the ports before we install the new battery voltage sensor.
    To do the work I purchased some lineman's gloves because I had a concern of working with high voltage; I purchase a clip remover and a torque wrench, and a new battery sensor. Most everything else I purchased previously. I did momentarily recall the approximate $1,000 labor charge that the dealership wanted. I am hoping that once we install the new sensor that any error messages regarding the hv will go away, or I will see if they can be reset.

    In the next few days I will send a copy of the pages of the repair manual which were of great assistance, especially since they include the torque wrench values of all bolts. I hope that anyone who has taken the time to read my posts derives some value from my experience as it is small compared to the help I received from others in this forum.

    Again, have a great holiday, which ever it may be during this season.
     

    Attached Files:

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  3. dubit

    dubit Senior Member

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    Vehicle:
    2016 Prius c
    Model:
    Two
    I wish you luck. When you say they spoke of corrosion, but you didn't find any. Are you sure they aren't talking about something like picture in this link? https://c2.staticflickr.com/6/5284/5249339465_7485990c6e_b.jpg

    But then again, it's a 2012 with the original HV battery. These battery packs don't age well in the C and from what one can read around here the life expectancy is about 5 years. They don't seem to be affected by mileage, rather it's "time" that kills the battery.
     
  4. Brooklyn_Boy

    Brooklyn_Boy New Member

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    Vehicle:
    2012 Prius c
    Model:
    Two
    Thanks Dubit. When we were told that there was corrosion they showed us a picture of the orange harness/connector to the battery voltage sensor. I recall specifically asking the service manager if the corrosion was inside the battery casing and was told that "we don't open the battery". In addition to learning how to replace the battery voltage sensor it appears that it would not take too much additional work to remove the battery completely; open the case, and inspect the areas that you identified in the linked picture.
    I undertook the sensor replacement with the understanding that the problem could very well be beyond that, and did so because the companies that were identified to install a replacement hv battery (1) only did that work onsite and (2) required the diagnostic tests from Toyota to confirm that a battery replacement was indicated.
    I really wasn't sure of the outcome but am hoping for the best. The dtc's started after 8 1/2 years (warranty up at 8) and approximately 58k miles. I've not heard from Toyota Corporate which depending upon the outcome of this work may be a moot point.
    Again, thanks for the wishes of luck.
     
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  5. RobAustin

    RobAustin Member

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    One
    Fingers crossed
     
  6. Brooklyn_Boy

    Brooklyn_Boy New Member

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    Location:
    St. Johns, Fl
    Vehicle:
    2012 Prius c
    Model:
    Two
    Thanks Rob. I appreciate your continued support and words of encouragement.
    Earlier today I replaced the battery voltage sensor and continued to reassemble the remainder of the car.
    I neglected to make mention that the old battery voltage sensor had some rust spots on the metal case front and back, and there were rust flakes on the portion of the hv battery wall where the sensor was retained. I cleaned the "rust flakes" before reinstalling everything. Started up the car...no hv battery warnings on the dashboard; no warnings whatsoever on the dashboard. The car runs smoother and the amount of hv battery strength is a bar or 2 higher.
    Let me again thank-you specifically, and everyone else from who gave their time and knowledge in contributing to my success in this endeavor. I continue to wince, though, when I recall that the dealership wanted about $4,000 to replace the battery sensor and hybrid battery, including (?) $900 labor. Although I do have to thank Toyota for their 2012 Prius C ESM (Electronic Service Manual). I didn't always understand it fully but it proved invaluable in so many ways.
     
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  7. RobAustin

    RobAustin Member

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    You're Welcome!
    and Merry Christmas
     
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