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dash ABS and all lights pertaining to brake system are lit.

Discussion in 'Gen 2 Prius Technical Discussion' started by Donald R. Hufham, Nov 25, 2018.

  1. Donald R. Hufham

    Donald R. Hufham New Member

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    When powering up for the first time after Hurricane Florence all the lights on dash came on pertaining to the brake system. The car sat on the street to which no flooding occurred only torrential rain and wind. They have remained on since. I did and out side inspection to see if anything might have been caught underneath to which I did not find. If anyone has a solution to testing and repairing this problem It would be greatly appreciated.

    Donald R. Hufham
     
  2. ChapmanF

    ChapmanF Senior Member

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    It will be helpful for you to post the brake-related trouble codes from your car so that we can begin thinking about what the problem(s) might be.

    If you don't have a scan tool able to read the trouble codes, you can also use a short length of wire and get the codes by counting light blinks, as you can find described in lots of posts here on PriusChat.

    -Chap
     
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  3. bisco

    bisco cookie crumbler

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    have you tested the 12v yet?

    how many miles on her?
     
  4. Skibob

    Skibob Senior Member

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    Could some water have gotten in by the battery compartment? There is a capacitor for the brakes there. Perhaps the connector got wet.
     
  5. Donald R. Hufham

    Donald R. Hufham New Member

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    Thanks for the reply's. Will report back ASAP with replies to each of your comments.
    Thank You
     
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  6. Donald R. Hufham

    Donald R. Hufham New Member

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    Good Morning, Thanks for the reply. Read the codes this AM and are as follows.
    Codes read are C1241, C1256, C1344
    Also is a picture of the dash lights
    Thanks
    Donald
     

    Attached Files:

  7. ChapmanF

    ChapmanF Senior Member

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    C1241 refers to unexpected voltage being measured at certain points internal to the brake system. It's not impossible for this to be related to the aux battery, but not a sure thing either; wiring, connections, or relays bringing power to the brake system can definitely be at fault.

    Internally, the brake actuator is split into two similar systems, "system 1" (powered by the ABS no. 1 relay), and "system 2" powered by the ABS no. 2 relay. Depending on what you used to read codes, you may be able to read a "detail code" for the C1241. If it's 81, then System 1 detected the issue; if it's 82, it was detected by System 2. Codes of 83 and 84 are also possible; they refer to the backup power capacitor module, or to a call for ABS "when the power source voltage of the main relay system is dropping", respectively.

    System 1 and System 2 have essentially identical detecting conditions: insufficient current reaching the linear solenoid when the brake is applied, or a voltage reaching the BS1 (respectively, BS2) terminal below 8.9 V for 3 seconds or more while the brake isn't applied, or the internally-regulated 5 volt supply going outside of 4.7 to 5.3 volts for more than a twentieth of a second.

    There are 8 pages of workup steps for this code in the repair manual, to pin down what's at fault. They do begin by checking to make sure there are no DTCs from the hybrid system (were you reading codes with a tool that can read the hybrid codes?), and checking that the aux battery is in the range 10 to 14 volts, charging or replacing it first if below.

    C1256 has to do with inability to pump up a suitable pressure in the accumulator. It can also have detail codes, 141 or 143, whose meanings are distinguished on the first of the two pages of workup instructions.

    C1344 reports a problem controlling the pressure in the left rear brake line. That can involve a leaky line, leaky SLA valve, leaky SLR valve, air in a line, or a warped rotor (not sure I've ever heard of that happening to a rear drum though). Detail codes (581 to 585) can distinguish some of those cases. Eight workup pages in the manual.

    -Chap
     
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  8. Donald R. Hufham

    Donald R. Hufham New Member

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    Any suggestions on this manual, at purchasing one. I do know the small battery had been replaced a couple of years ago. This was my wife's car and had been well taken care of. Strange how just sitting through a hurricane Florence on the street and not flooded just heavy winds and rain. Could there be a stick or some moisture that creates this problem ? I have been wanting to put it on a lift and inspect connections. Everything works perfect other than these lights lite. My Wife has a 2013 and it sat through the same with no issues.
    Donald
     
  9. ChapmanF

    ChapmanF Senior Member

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  10. Skibob

    Skibob Senior Member

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    Plus here is a tip on how to set up your computer to print those pages
    Toyota TIS download tips | PriusChat
    I would set it up and make sure it works before I paid the 20 dollars. Good time to download any other Toyota manuals you need at the same time. ;)