ABS Light on - Know how transistors work? - New sensor 400$?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by GenIFTW, Jun 11, 2014.

  1. GenIFTW

    GenIFTW New Member

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    Jun 11, 2014
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    Location:
    Victoria
    Vehicle:
    2003 Prius
    Model:
    I
    Ok, so firstly I apologise, this is for a Gen I but there isn't a forum, and I can explain everything I need to. The ABS light is on on my Gen I prius and the dealership said something is up with one of the sensors and it will take 3-4 weeks to order the part from Japan (and they have quoted me $400? Think I can get this sort of thing secondhand?)

    I tried "clearing the codes" by connecting pins 4 and 13 with a safety pin and pushing the brake. It cleared the light while in that diagnostic mode, but it comes back on when I remove the pin and the car is turned on again.

    I want to disable the ABS light until the new part arrives, and have looked at the wiring manual:
    http://we0h.us/Prius/Service-Manual/Gen-I-Wiring-Diagram/2003-Prius-Electrical-Wiring.pdf

    Page 184 indicates that this light supplied with power, and the on/off state is controlled by C10(10), marked as 10A and a blue wire in the bottom middle of the page 184 diagram. I don't understand circuit diagrams/transistors well enough to know whether disconnecting this wire will turn the light off, or if it will put it into a state of default on.

    If anyone could advise it would be greatly appreciated, I can even tip you $10 in bitcoin if you can give me a (relatively) safe fix to disable this light temporarily.
     
    #1 GenIFTW, Jun 11, 2014
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Vehicle:
    2015 Prius
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    Two
    1. Yes, you might be able to obtain a used sensor although it may be difficult since the Classic Prius was produced in very low quantity (only ~50K units sold in the US over the three model years.) First, research the part number on toyodiy.com, then look on eBay.

    2. You should not take the wiring diagram very literally, with regard to connections inside an electronic assembly like the combination meter. It is intended to give you a rough idea of what is going on. In this particular case, the idea is that a positive voltage supplied by the blue wire will forward-bias the NPN transistor which will cause the transistor to conduct and the ABS light in the collector circuit to turn on.

    3. I suggest that you leave the wiring as is, to avoid causing unintended consequences to the brake system. If the light really bugs you, place a piece of black electrician's tape over it.

    4. The Classic Prius forum can be found here: Generation 1 Prius Discussion | PriusChat

    5. I am not interested in bitcoin but if you start talking PayPal, then I would be interested.
     
    #2 Patrick Wong, Jun 11, 2014
    Last edited: Jun 11, 2014
    GenIFTW likes this.
  3. GenIFTW

    GenIFTW New Member

    Joined:
    Jun 11, 2014
    6
    0
    0
    Location:
    Victoria
    Vehicle:
    2003 Prius
    Model:
    I
    Ok I found a guide to replacing the sensor on an MR2, which I think should give me enough to work with to find it on the prius and make sure the wiring is connected etc, I just need to find the part, which I imagine will be hard in Australia but I think I know a wreckers which would have one as they have majority of the same model prius.

    Regarding point 2, definitely now starting to think it is a bad idea, but theoretically the disabling of this wire would prevent the transistor from conducting?
     
    #3 GenIFTW, Jun 11, 2014
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