Multiple warning lights simultaneously (PCS, ABS, Parking Brake...)

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by jquat, Feb 16, 2022.

  1. jquat

    jquat New Member

    Joined:
    Feb 16, 2022
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    Location:
    MA, USA
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Advanced
    I have searched these forums and have found similar issues, but no definitive answer (perhaps impossible, but I am hopeful). Prius is nearing 190k miles, and has generally been trouble free.

    Multiple warning lights have come on (and turned off) without warning (I have attached photos):
    PCS (And Check PCS System)
    ABS
    Parking Brake
    (Circle with exclamation point)
    Traction Control (Or slip warning?)
    Yellow Triangle with Exclamation Point
    It I try to turn on the radar cruise control system, it will not work and I also get a warning.

    The most troubling thing, is that all these warning lights will suddenly go off mid-drive as well as if nothing happened, and don't seem to store in the computers memory as having happened (this from using the hold info and turn lights on 3 times trick to access the car computer and saved errors). Sometimes I will drive with nothing happening, and other times they will come on and turn off multiple times during a short drive.

    When the warnings come on, it is notice that there is no regenerative braking, and the cruise system will not operate.

    Possible related known causes/events:
    -My 12v battery reads at 11.6v to 11.7v, and I believe it's the original from 2012, but otherwise no issues
    -I was in usually cold weather recently (-15F)
    -I jumped a car successfully in said cold weather, and it seemed like it ran the car flickered it's displays while doing so (I probably drove 500+ miles after that with no issues).

    I've seen so many suggestions for similar issues from changing the battery, to the wiring harnesses, to resetting the pcs etc... Any logical steps to follow considering these circumstances? I don't mind paying for it to be fixed properly, but I'd like to avoid a high priced bill only for it to be something else.

    Thank you!
     

    Attached Files:

    #1 jquat, Feb 16, 2022
  2. Merkey

    Merkey Active Member

    Joined:
    Dec 18, 2012
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    Location:
    Birmingham, Michigan
    Vehicle:
    2010 Prius
    Model:
    II
    My 2010 has the same problem. Dealer determined it's a rear wheel sensor.
    About $800 for parts and labor. Waiting now for parts to come in.
     
    #2 Merkey, Feb 16, 2022
  3. ChapmanF

    ChapmanF Senior Member

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    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    The only really logical step to follow is to ask the car for the trouble codes that explain why those lights were turned on.

    Because there are on the order of a couple hundred possibilities, it doesn't make much sense to guess, nor to assume that your car's one out of two hundred reasons is going to turn out to be the same one out of two hundred that it was in somebody else's car where the same lights came on.

    If you don't have a scan tool that can retrieve those trouble codes for you, the good news is Gen 3 is built so you can get the codes from skid ECU (which will give you the reasons behind the ABS, ((!)), and skidding-car lights on the dash) using a short piece of wire between the Tc and CG terminals at the car's diagnostic connector, and counting the blinks of the dash lights. Other threads in this forum have the details on that, if you search a bit on those terms.
     
    #3 ChapmanF, Feb 16, 2022
    Last edited: Feb 16, 2022
    Merkey likes this.
  4. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
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    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    There must be some codes. Check with something like Dr Prius app, or get dealership or automotive store on it.
     
    #4 Mendel Leisk, Feb 16, 2022
  5. ChapmanF

    ChapmanF Senior Member

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    Vehicle:
    2010 Prius
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    IV
    From posts I have seen about Dr. Prius, I'm not sure if you can get skid ECU codes with it. It seems to have a screen to show engine codes, and one to show battery codes, and nothing for codes from the other twenty or so ECUs in the car.

    But probably there is another phone app that will work with the same dongle Dr. Prius is using, and can read codes from other ECUs. Or the blink-the-dash-lights method can be used, at least for the skid ECU codes, which does an end run around all the "can my scan tool read them" questions.
     
    #5 ChapmanF, Feb 16, 2022
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