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ABS and Brake light come on with high pitched sound

Discussion in 'Generation 1 Prius Discussion' started by pri415, Aug 2, 2015.

  1. pri415

    pri415 New Member

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    I'm new to this forum and a first time poster. I have a 2002 prius with 147612 miles on it and a problem with my braking system. When I turn on the car the ABS and Brake light turn on and there is a high pitch sound that beeps continuously. Sometimes after a while the warning lights and beeping stop only to return a little while later. I can drive the car when the warning lights are on but i have to press harder on the brakes than normal to get the car to stop and the braking system feels looser. However, when the warning lights turn off I can brake as i normally do and the system feels normal. This problem goes on intermittently as I'm driving.

    I took the car to the dealership today and paid $143 for a diagnostics and was told that DTC C1251 was retrieved from the diagnostic computer. The technician told me that the ABS Motor is bad and because of that the car thinks i'm skidding so the ABS shuts off. He recommended that I get the ABS Motor ASSY ( Part #47071-47010) replaced and quoted me a price of $2215 for parts and labor.

    So now I'm turning to priuschat to see what my options are and what the experts here recommend that I do. Would you recommend that I buy a used part to save on repair cost? Also, I read a post where someone had a similar problem and was able to resolve it by flushing the brake fluid. I checked the brake fluid level in the cylinder and it is at the max level and there aren't any leaks. Would that be an option? How much do you think is reasonable to spend for this repair? I bought this car 15 months ago for $4000.

    Any help will be greatly appreciated. Thanks!
     
    #1 pri415, Aug 2, 2015
    Last edited: Aug 2, 2015
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, based upon the reported DTC you would need to replace the brake actuator assembly which includes the motor. You could have a used part installed.

    Do not continue to drive the car in its current condition as the braking system is quite marginal, evidenced by the high pitched warning sound.
     
    #2 Patrick Wong, Aug 2, 2015
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  3. pri415

    pri415 New Member

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    Thank you for your reply. Would this part be all I need to give to my mechanic?
     
    #3 pri415, Aug 2, 2015
  4. pri415

    pri415 New Member

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    sorry I meant would this be all I need? Image attached
     

    Attached Files:

    #4 pri415, Aug 2, 2015
  5. ChapmanF

    ChapmanF Senior Member

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    We need to be careful with terminology because this is a Gen 1, where the 'actuator' is toward the center/left on the firewall and does not include the pump, and the 'accumulator' is on the far right and includes the pump. The picture you attached is indeed the accumulator and is probably what you need. I would avoid saying 'actuator' at all because that's a whole other can of worms and probably not what you need, and may confuse people.

    (I'm saying 'left' and 'right' for someone facing the same way the car does.)

    For Gen 2 I think they did combine things differently and stuck the pump on the actuator, but that's the wrong car.

    The dealer tech is probably right about the part you need, even though his explanation of why is totally out of left field. The real explanation is way simpler than the stuff he made up. That motor runs a pump that pressurizes the brake fluid to assist your braking. Not running, no pressurized fluid, no assist, hard braking, just as you experienced. The car doesn't "think you're skidding" or any such rot. The ABS computer monitors that pump and motor very comprehensively, it knows exactly what's happening, and using the warning lights and buzzer to tell you about it.

    There are about three pages of diagnostic steps in the service manual (at techinfo.toyota.com) for a code C1251. They can help narrow down whether the whole accumulator assembly is needed, just the pump motor part of it, or perhaps a wiring repair. The dealer tech might not be interested in doing anything beyond making up a weird explanation and throwing in the complete accumulator (which probably will fix the problem, unless it's really in a wire harness or the brake ECU), but if you know any bright indy mechanics you might find one who'd be interested in tracing through those steps before deciding exactly what you need.

    -Chap
     
    #5 ChapmanF, Aug 3, 2015
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  6. ChapmanF

    ChapmanF Senior Member

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    There is a thread from a while back by a member rlin78 who managed to install an accumulator DIY and without having to evacuate/recharge the air conditioning (something the standard procedure includes just because the lines are in the way) ... but did report that doing it that way took about ten hours.

    -Chap
     
    #6 ChapmanF, Aug 3, 2015
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  7. pri415

    pri415 New Member

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    Thanks a lot for your thorough response, it really helped. I will try to get this fixed this week and report back with the results. I just really want to avoid paying half my purchase price to do this repair.
     
    #7 pri415, Aug 3, 2015
  8. pri415

    pri415 New Member

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    Just following up. Thanks for the help everyone! I had my mechanic install a used accumulator assembly in 8/15. He did everything in front of me on a side walk in an hour or so with a bit of assistants from me( that's a whole different story altogether). When he showed me the brake fluid, it had some water in it and was really old. I was amazed at how he was able to get his hands and the part in such a tiny space without taking the whole engine out but he somehow managed. All on all, it costs me $390 total for used part and labor. Dealer was asking for 2k +. Haven't had any issues with braking system since.
     
    #8 pri415, Mar 2, 2016
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  9. pri415

    pri415 New Member

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    As far as the air conditioning, I remember that there wasn't any fluid in the air conditioning system so he didn't have a problem taking that apart in order to install the accumulator
     
    #9 pri415, Mar 2, 2016
  10. ChapmanF

    ChapmanF Senior Member

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    Did you have the mechanic recharge the A/C after reconnecting the lines, or try to find the leak anyway, since you found it had no charge? Or at least draw a vacuum on it and leave it that way, assuming the leak is small enough, it might stay mostly evacuated for a while.

    That way at least you could resurrect the A/C at some future time if you wanted ... if it sits too long with moist atmospheric air inside that got in when the lines were open, maybe not so much.

    -Chap
     
    #10 ChapmanF, Mar 3, 2016
  11. 123notme

    123notme New Member

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    The hole is on the right side of the wheel between the break and gas pedals. A temporary fix until you get it fix at an auto shop.
     
    #11 123notme, Sep 3, 2021
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