Pre Collisions System Malfunction and Braking Power Low warning

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by Franklin Corn, Dec 11, 2023.

  1. Franklin Corn

    Franklin Corn New Member

    Joined:
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    Location:
    Oklahoma
    Vehicle:
    2018 Prius
    Model:
    Two Eco
    Hello everyone,

    I have a 2018 Prius two eco and I was driving down the road when it told me I have .6 miles to find a safe place to park. Then it started displaying the following messages:

    Check Engine
    Visit Your Dealer

    Pre-Collision
    System Malfunction
    Visit Your Dealer

    Brake Power Low
    Visit Your Dealer

    I also check with a OBD2 and the code I am getting is P3190.
    I have checked all of the ECU fuses
    I also had the 12 volt battery checked and they had to charge it before getting a successful test. It tested good.
    At this point I think I need to change the ECM/ECU but cannot seem to find its location on Google. Seems like gen 4 info isn’t as available as older gens

    Has anyone else seen this problem?
     
    #1 Franklin Corn, Dec 11, 2023
  2. BiomedO1

    BiomedO1 Senior Member

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    Vehicle:
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    Model:
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    Why do you think you have a bad ECU, they rarely fail unless the car's been under water? You can't simply drop a used ECU into your car, unless it's the same year, make, model, options, and sometimes even software/firmware revisions. The serial numbers won't match, if your state requires annual safety checks.

    The code you posted points to poor engine performance, yet your describing a brake, traction control malfunction issue. Is or was this a previously salvaged vehicle?
     
    #2 BiomedO1, Dec 12, 2023
  3. Franklin Corn

    Franklin Corn New Member

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    Vehicle:
    2018 Prius
    Model:
    Two Eco
    Thanks for the response.

    Ecu is what the OBD2 reader read so I assumed because I don’t know where else to start. one day it said Hybrid Malfunction. So it has different messages sometimes.

    I’ve had this car since it was brand new. I’ve never had any other problems with it.

    I’ve also heard bad gas could cause it or low oil. There are a lot of directions to troubleshoot. I am trying to narrow that down.
     
    #3 Franklin Corn, Dec 12, 2023
  4. BiomedO1

    BiomedO1 Senior Member

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    Start with the basics, rather than trying to throw parts at it.
    In your case, you can actually save money by taking it to a certified Prius specialist for diagnostic.
     
    #4 BiomedO1, Dec 13, 2023
  5. AzWxGuy

    AzWxGuy Weather Guy

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    The earlier fact that your 12V battery required charging may be key to the vehicle throwing questionable codes. Prius has always acted randomly like this when the 12V is low. When you had the 12V battery checked did they stress test it? They typically last for at least 5 years, which may be about time if it is EOM.
     
    #5 AzWxGuy, Dec 13, 2023
    amos likes this.
  6. Franklin Corn

    Franklin Corn New Member

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    Vehicle:
    2018 Prius
    Model:
    Two Eco
    It would be good to rule out for sure.
     
    #6 Franklin Corn, Dec 13, 2023
  7. AzWxGuy

    AzWxGuy Weather Guy

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    Meant to say OEM, original equipment manufacturer. The original battery that came with the car.
     
    #7 AzWxGuy, Dec 14, 2023
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