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Intermittent Braking Issue

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Laura Pederson, Oct 8, 2014.

  1. Laura Pederson

    Laura Pederson Junior Member

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    2004 Prius
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    I have a 2004 Prius with 215,o00 miles. I have had minimal issues with the vehicle besides in 2010 having to replace a few of the hybrid battery modules. The car has had all of its recall work taken care of, including the issue where the dashboard goes black and the car won't turn off (my vehicle actually experienced this). Unfortunately, now the car is experiencing problems.

    For the last two months, my car is having intermittent braking issues. I drive a lot for work, and this braking issue happens anywhere from twice a day to every three days. If I decompress the brake in one even motion, it is as if the braking does not kick in until later than it should and the car suddenly jolts. As I continue to compress the brake, the same thing happens a few more times until the car is fully stopped. It is almost as if the car did not get the signal that I was braking at first, and then it processed it all at once. This causes the car to jerk like I am slamming my brakes. The intermittent problem can last for the entire trip or it can stop midway through the trip. I have tried to turn the car on/off at stop lights before to see if it will "reset" itself with no avail.

    I assumed my brake rotors/pads were failing, even though the rotors were machined at the Toyota dealership a few months before. I took it back to the dealership on a day this issue was particularly bad, but the issue stopped before I made it to the dealership. They confirmed that my actual brake system was fine, but told me that unless they can duplicate the issue, they are unable to diagnose it.

    The braking issue continued intermittently. Every time it was particularly bad and I would drive towards the dealership for them to examine the car, it would stop on the way over.

    Yesterday, the issue was very bad for the majority of the day. I went to the dealership and the issue stopped on the way over again. They confirmed once again that they cannot do anything without a dashboard light to hook it up to their diagnostic computer or experiencing the issue themselves. Then on the way home, the braking issue began again.....

    It's my first time posting on the Prius Chat Forum so let me know if I need to include any other information.

    Thanks for your help!
     
    #1 Laura Pederson, Oct 8, 2014
  2. northwichita

    northwichita .

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    Location:
    Wichita KS
    Vehicle:
    2004 Prius
    I would ask the dealership to flush out the old brake fluid and bleed the brakes, brake fluid can absorb moisture, there may be air in the system, even if this doesn't solve the problem, it is good for your brake system to have fresh fluid in it.

    I happened to have somewhat of the same problem, and brake bleeding helped my car, but I eventually had to replaced my brake actuator (which I could hear running excessively). I do use my car as a rural route postal vehicle, so I brake much of the day .
     
    #2 northwichita, Oct 8, 2014
    Last edited: Oct 8, 2014
  3. exstudent

    exstudent Senior Member

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    I'm assuming they tried to pull any error codes w/ Techstream software, but found no codes. They also test drove it and no problems what so ever.

    Front brake pads and rear brake shoes had enough braking material left? NO glazing as well?

    Front brake caliper pins? Were those checked and relubed?

    Rear brake shoe mounts? Were those cleaned and regreased?
     
    #3 exstudent, Oct 8, 2014
  4. bisco

    bisco cookie crumbler

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    welcome to priuschat! maybe your brake accumulator is leaking. you might want to try another dealer. they might need to keep it overnight and try it cold in the morning.
     
    #4 bisco, Oct 8, 2014
  5. iamcolleen2

    iamcolleen2 New Member

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    2004 Prius
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    Hello, I just found this thread and I am experiencing the very same issue with my 2004 Prius. Mine has 174,000 miles, and this braking problem has been happening for about three months, the first time it ever happened was in July. I had it checked out and they could not find any error codes, and (of course) it didn't happen when they tested it. It is very frustrating because it is so random, it will go a week without happening and then suddenly happen every time I brake for a day and then stop again. I like Laura's description of it, I would also describe it as if the car is trying to drive through the brake. The car always stops eventually but it is very jerky and scary at first when you press the pedal and nothing happens.

    I'm interested to see if anyone else is having this issue or if anyone else knows what it could be.
     
    #5 iamcolleen2, Nov 9, 2014
  6. bisco

    bisco cookie crumbler

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    too bad laura never came back.
     
    #6 bisco, Nov 9, 2014
  7. JoeDoe

    JoeDoe New Member

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    Vehicle:
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    Hello, was this issue ever resolved? I am having the same issue now.

    Hello, was this issue ever resolved? I am having the same issue now.
     
    #7 JoeDoe, May 11, 2021
  8. JoeDoe

    JoeDoe New Member

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    2014 Prius
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    Two
    To whomever may have this issue in the future I believe I solved it. The following is everything I did. I am not sure if all of this needs to be done or just some of it or just the very last thing but my car has not had this issue in months so I believe it is remedied.

    #1. Changed to front brake pads (mine were terrible, but I still had the same issue after new pads were put in).
    #2. Replaced the brake pedal position sensor (bought one used off ebay). This was a pain in the butt to install due to its location, but it is doable. Watch several how to install videos on youtube before trying to install this and beware that there is a moving plastic lever part that (when buying a used part) will need to be held in place manually while installing (I believe a brand new one would have this lever piece held in the right spot by another plastic piece that then gets broken off after installation so that it will function - I know this I difficult to understand but once you have the part in front of you, it should make more sense). After installing this part, the issue was even worse than before so I then...
    #3. Cleared all codes using techstream software. After clearing codes, everything went back to normal and my problem was solved. I am not sure if doing this from the beginning would have solved the problem but I doubt it. My guess is that I needed to do #2 then #3 to fix the problem.

    Good luck to anyone who reads this and I hope it works for you all like it did for me. Peace.
     
    #8 JoeDoe, Aug 30, 2021
    bisco likes this.
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