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Intermittent won't start

Discussion in 'Gen 3 Prius Technical Discussion' started by ep1, Mar 19, 2023.

  1. ep1

    ep1 Junior Member

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    Hi:
    My daughter's 2013 Prius(90k miles) has an intermittent won't start issue.
    Seems to occur more often when the car has sat for a while and is cold.
    It is not the 12V battery.
    No error codes.
    Just noticed that when system won't start correctly, there is a creaking sound, may be twice or three times coming from the left side of the engine compartment close to the ABS unit. ABS unit does make its own whirling sound as it initializes.

    Today, I noticed something. Before pressing the "power" button to start the car, if I sit in the car and just press and hold the brake pedal, a creaking sound will be heard. If I press the "power" button the car will not start even though the dash board and LCD screens go through their boot up sequence. The car won't go into gear and nor move.

    I press the "power" button again to turn off the car, and then just press and hold the brake pedal and listen for the creaking sound, and then release the brake pedal and listen again, and repeat. When I don't hear the creaking sound, if I press the " power" button the car will start up fully and can move.

    Any ideas what is making the creaking sound ? Or what the symptoms indicate ?

    P
     
    #1 ep1, Mar 19, 2023
  2. JC91006

    JC91006 Senior Member

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    Probably dealing with a bad brake switch. Car can't tell if the brake is pressed so car won't start.
     
    #2 JC91006, Mar 20, 2023
  3. Brian1954

    Brian1954 Active Member

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    Can you please describe how you checked the 12v battery and determine that it is ok.

    Posted via the PriusChat mobile app.
     
    #3 Brian1954, Mar 20, 2023
  4. ChapmanF

    ChapmanF Senior Member

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    A recording of the "creaking sound" also might not hurt.
     
    #4 ChapmanF, Mar 20, 2023
  5. ep1

    ep1 Junior Member

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    Hi:
    thank you for the replies:
    1) battery is new ~ 1year old Optima
    checked battery with my trusty Fluke 287
    took the surface charge of the battery by running the headlights for a few minutes
    ~ 13V
    2) Brake pedal switch is working
    press the pedal:
    brake lights go on
    indicator light in the "Power button" changes color
    3) creaking sound that is heard after pressing and holding the brake pedal
    I should have done that, but my daughter drove a hundred miles back to her place before I could.
     
    #5 ep1, Mar 20, 2023
  6. tw0leftskis

    tw0leftskis New Member

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    That sound coild possibly be there brake actuator. Making a squawking sound.
    Is it a chirp noise?
     
    #6 tw0leftskis, Mar 21, 2023
  7. ep1

    ep1 Junior Member

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    To my ear, the sound is not short in length like a chirp. It sound like a creaking wooden floor. The sound seems to be emanating from the area close to the abs unit. May be the next time I will slide under the car and have my daughter press the brake pedal .
    It creaks a few seconds after pressing and holding the brake pedal
    P
     
    #7 ep1, Mar 21, 2023
  8. ep1

    ep1 Junior Member

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    Found a yourtube video of the sound.

    P
     
    #8 ep1, Mar 22, 2023
  9. bisco

    bisco cookie crumbler

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    maybe a vent door or the 3 way coolant valve, but the only thing the brake should affect is the actuator master cylinder assy.

    and none of those should prevent the car from starting. i would still get a free load test
     
    #9 bisco, Mar 22, 2023
  10. ChapmanF

    ChapmanF Senior Member

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    In that video I am hearing both: (1) the expected sound of the brake pressure pump occasionally (the quiet whirr or joy-buzzer sound that clicks on for a second or so and clicks off again, and (2) the often-discussed brake "bark" or "quack" or "honk" sounds, which are the shorter, louder, more irregular ones.
     
    #10 ChapmanF, Mar 22, 2023
  11. ep1

    ep1 Junior Member

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    It is the brake accumulator/pump. Turns out there is a "Customer Support Program ZJB" for this issue.
    There were also issues in the Gen 2 Prius, and other Toyota Hybrids regarding the braking system.
    Thanks for the comments.

    Just to reiterate, if I just hear the pump's whirring sound then the car will go into gear and move. I hear the creaking sound( bark/quack/honk) then the car won't go into gear and not move.


    P
     
    #11 ep1, Mar 23, 2023
    bisco likes this.
  12. ChapmanF

    ChapmanF Senior Member

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    Multiple things may be going on. Many people experience the bark/quack without a problem selecting gears or moving.

    When you can't select a gear or move, I would really expect the triangle light to be on, and for there to be codes. If so, it would be helpful to know what the codes are.
     
    #12 ChapmanF, Mar 23, 2023
  13. ep1

    ep1 Junior Member

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    No idiot lights on. I don't have a dedicated diagnostics scanner for the Prius, so I can't see any error codes. I only have a simple OBDII scanner for emissions related codes, no codes. This issue is intermittent. The car will always eventually move but sometimes it can take 5~ 10 minutes of trying.
    When I called a toyota dealer's service department, they said the vin was in a range of suspects.
    P
     
    #13 ep1, Mar 23, 2023
  14. ep1

    ep1 Junior Member

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    It may have been the 3.5 year old Optima battery after all. I finally used the dashboard diagnostics to check the 12 V battery voltage before and after the HV propulsion battery starts to charge it. I think that is why after repeated attempts to start the car, the inverter will bring up the 12 V battery up enough that the hydraulic brake pump can operate ? With a new battery in for the past two days, no issues starting. I guess not driving a car much is harder on the 12V battery than if it was regularly used!
    Will update in a few weeks.
    P
     
    #14 ep1, Apr 13, 2023
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