Emergency brake, ABS, and (!) lights on

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by slickvik, Jun 4, 2020.

  1. slickvik

    slickvik Junior Member

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    Three lights just turned on in my 2007 prius:

    Emergency brake
    ABS
    (!) brake system warning light

    I only had a mile to drive when the lights turned on, and the brakes still worked. When I restarted the car the next time they did not show up. Is this a one time issue or possibly the speed sensor?

    I just changed my actuator 6 months ago so it can't be that.
     
    #1 slickvik, Jun 4, 2020
    Last edited: Jun 4, 2020
  2. SFO

    SFO Senior Member

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    Happen to have any OBD2 codes (DTCs) that you can share with us?
     
    #2 SFO, Jun 4, 2020
  3. slickvik

    slickvik Junior Member

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    No, the local hybrid shop is charging $125 to read techstream codes. So I'm thinking of buying a mini VCI to get an idea at least. I'm driving another car in the meantime.
     
    #3 slickvik, Jun 4, 2020
  4. SFO

    SFO Senior Member

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    #4 SFO, Jun 4, 2020
  5. slickvik

    slickvik Junior Member

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    #5 slickvik, Jun 4, 2020
  6. SFO

    SFO Senior Member

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    Not sure which device you're using, but after reading that webpage it appears that the carista product accommodates both platforms.
     
    #6 SFO, Jun 4, 2020
  7. slickvik

    slickvik Junior Member

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    I'm leaning towards VXDIAG VCX Nano as it seems that Tactrix 2.0 Openport isn't perfect with Generation 2 prius.
     
    #7 slickvik, Jun 4, 2020
  8. dolj

    dolj Senior Member

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    Out of interest, What makes you think that?
     
    #8 dolj, Jun 5, 2020
  9. ChapmanF

    ChapmanF Senior Member

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    I think I said so somewhere. I have an Openport, and I bought it because the Mini VCI that I already had tended to flake out on my Gen 3. Then one day, I was trying to work on somebody's Gen 2, and whatever I was trying to do (forgotten now) didn't work, and I dug out the Mini VCI and it worked.

    There are no more details in my sieve at the moment.
     
    #9 ChapmanF, Jun 6, 2020
    SFO likes this.
  10. slickvik

    slickvik Junior Member

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    Code is C1249. Forgot to mention in first post that VSC light was on also. Strangely enough, these lights never came on again.
     
    #10 slickvik, Jun 23, 2020
  11. dolj

    dolj Senior Member

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    What do you mean by this?
    DTC C1249 (Blink code 49) | Open in Stop Light Switch Circuit

    DESCRIPTION
    The skid control ECU inputs the stop light switch signal and detects the braking condition.

    The skid control ECU has a circuit for open detection inside. The skid control ECU outputs the DTC if it detects an open in the stop light signal input line when the stop light switch is off, or an open in the stop light circuit (GND side).

    DTC No. Blink Code INF Code DTC Detection Condition Trouble Area
    1 C1249 49 520 The stop light switch circuit is open for at least 10 sec. when IG1 terminal voltage is between 9.5 V and 17.02 V
    • Stop light switch
    • Stop light switch circuit
    • Stop light bulb


    See DTC C1249 Inspection Procedure for the complete inspection procedure.

    Let us know how you get on.
     
    #11 dolj, Jun 24, 2020
  12. slickvik

    slickvik Junior Member

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    To your initial comment, what I mean is these 4 lights came on once when I started the Prius a few weeks ago, but never since then.
     
    #12 slickvik, Jun 24, 2020
  13. dolj

    dolj Senior Member

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    And they are still off now? If so, you do not have any faults to investigate currently.
     
    #13 dolj, Jun 25, 2020
  14. AzusaPrius

    AzusaPrius Senior Member

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    Change out the rear wheel hub assembly. This is a speed sensor issue and takes a while until the speed sensor error shows up. In the meantime your hybrid battery is taking a hit.

    Posted via the PriusChat mobile app.
     
    #14 AzusaPrius, Jun 26, 2020
  15. dolj

    dolj Senior Member

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    How do you know this? Are there any codes at present? The OP has indicated all the idiot lights are off (not lit), so this would indicate there is no fault at present.
     
    #15 dolj, Jun 29, 2020
  16. Gino Veltri

    Gino Veltri Member

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    Can you please explain this? why does the hybrid battery take the hit from a speed sensor issue? Thanks in advance!
     
    #16 Gino Veltri, Oct 4, 2021
  17. mr_guy_mann

    mr_guy_mann Senior Member

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    If there is a fault with the braking system, then the hybrid control will usually disable regenerative braking. AFAIK the car will still charge the HV battery from ICE operation, but no regen, so there's a hit to mpg.

    Posted via the PriusChat mobile app.
     
    #17 mr_guy_mann, Oct 4, 2021
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