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Combo Problem: Yellow Brake Indicator Light, Noises

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by EazyMack, Aug 7, 2013.

  1. EazyMack

    EazyMack Intelligently Designed

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    Hey folks. I did a forum search but was unable to dig up anything with a combo problem like the one I am having.

    I have a 2004 Prius. The yellow brake warning indicator light is on. I also notice that there is a noise coming from under the hood near the dash whenever: a) I open the driver's side door; b) the car is on or running, including while driving; c) for about a minute or so after shutting the car off... unless I again open the driver's side door. The noise comes on and off, on and off, in any of these scenarios. On for about 3-5 seconds, off for about 3-5 seconds, and on again.

    I used to have another 2004 Prius before, and I remember this sound, but I only remember the sound from pressing the brake to start the car, and right after turning the car off, and only for a few seconds.

    So I am wondering if the two issues are related... perhaps a regenerative braking thing?

    I'd rather do some research before shelling out money to the dealer/mechanic. Any help is appreciated.
     

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    #1 EazyMack, Aug 7, 2013
  2. xpcman

    xpcman Senior Member

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    Get to the dealer right now. Brakes are not something you want to do a cheap fix on. The Prius brakes are also best left to a qualified PRIUS mechanic.
     
    #2 xpcman, Aug 7, 2013
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, your brake system has a problem and if you can obtain the DTC logged by the skid control ECU (which a generic OBD-II scanner will not be able to read), maybe we can comment on what is causing the problem.
     
    #3 Patrick Wong, Aug 7, 2013
  4. vskid3

    vskid3 Active Member

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    Low brake fluid maybe?
     
    #4 vskid3, Aug 7, 2013
  5. EazyMack

    EazyMack Intelligently Designed

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    Brake fluid is good.

    Definitely sounds like something is charging/pumping, or retracting, or something like that.

    I don't have a scanner. Guess I'll have to get it checked out.
     
    #5 EazyMack, Aug 7, 2013
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    It could be that the brake pressure accumulator is not maintaining hydraulic pressure, hence the actuator pump is running more than normal.
     
    #6 Patrick Wong, Aug 7, 2013
  7. EazyMack

    EazyMack Intelligently Designed

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    Would you be able to tell by the sound of it? I could post a video (w/audio of course) if helpful.
     
    #7 EazyMack, Aug 7, 2013
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Given your car's described symptoms, I can say that the problem is not going to be something you can deal with yourself so it would be best for you to have the DTC read and a diagnosis provided to you.
     
    #8 Patrick Wong, Aug 7, 2013
  9. EazyMack

    EazyMack Intelligently Designed

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    Yes, I took it to the dealer (after the ABS, VSC, and red BRAKE lights came on). They told me the brake control power supply needed to be replaced.

    So... I replaced it. Drove it a few miles. Lights still on, still makes that noise every few seconds (see OP). I tried disconnecting & reconnecting the battery as well, but no difference.

    What could I be missing?
     
    #9 EazyMack, Aug 19, 2013
  10. EazyMack

    EazyMack Intelligently Designed

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    The code that came back was C1377, by the way.
     
    #10 EazyMack, Aug 19, 2013
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, that does point to the brake control power supply (located next to the 12V battery). Did you install a new part or a used part?

    Since you are continuing to have the same symptoms, check ABS fuses 1, 2, and 3. The wiring harness also is a potential problem. If you have a voltmeter to verify voltages, see techinfo.toyota.com for the repair manual pages which describe how to troubleshoot the wiring connections.

    If you don't find any problems, you probably need to have the DTC retrieved again to see whether the problem is still C1377 or some other issue.
     
    #11 Patrick Wong, Aug 19, 2013
    Stimp likes this.
  12. EazyMack

    EazyMack Intelligently Designed

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    I installed a used part. What are the odds the used part could have the same problem?

    I will check the fuses. Thank you for the help!
     
    #12 EazyMack, Aug 21, 2013
  13. EazyMack

    EazyMack Intelligently Designed

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    The fuses look fine.

    If it were just the warning lights, I would think they just needed to be cleared again (I did not disconnect the 12V when switching out the brake control power supply)... but it still makes that same noise under the hood every few seconds.

    The dealer was going to charge $690 to swap out the power supply. Does that sound right?
     
    #13 EazyMack, Aug 21, 2013
  14. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Did you remove the fuses, one by one, to measure resistance with an ohmmeter? Do not rely upon a visual inspection.
     
    #14 Patrick Wong, Aug 21, 2013
  15. Stimp

    Stimp Member

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    I came up with a C1377 code. Suspected it could be a fuse, just didn't know where to start. Quick search brought me here, and ended up being the 15A ABS fuse.(y)
     
    #15 Stimp, Feb 21, 2019
  16. ILuvMyPriusToo

    ILuvMyPriusToo Senior Member

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    Good for you! Excellent. (y)
     
    #16 ILuvMyPriusToo, Feb 21, 2019
  17. dolj

    dolj Senior Member

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    The question is why the 15A ABS fuse blew. I wouldn't call it fixed until I knew the answer to that question.
     
    #17 dolj, Feb 21, 2019
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  18. Stimp

    Stimp Member

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    Because there was a mishap, wires got severed and shorted. Luckily it was very limited, and I got it back to normal. Car was operating just fine with the blown fuse and (!) light. Obviously a safety concern if the ABS didn't operate.The only other fuse that blew was for the door locks, and it was easily diagnosed.
     
    #18 Stimp, Feb 22, 2019
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