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ABS brake issue C1345 Linear valve offset undone

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by smokeGTI, Aug 6, 2021.

  1. smokeGTI

    smokeGTI Member

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    Hi all,
    A little back ground, the car is 2009 Gen 3 with est. 155,xxx km on clock,
    Been learned the linear valve offset couple of times during pass years while the
    hiss noises was heard when stopping in a hurry . And it always cured after re learned.

    But not this time together with code C1203 -"ECM/EV Communication Circuit".
    Have checked all fuses are fine. So normally when you learning the Linear valve, the ABS and brake lights
    should blinks, then finishing with faster blinks.
    So when I perform the learning this time they would not blink, and I was never able to reset it anymore.
    Any idea of where to look in to ?
    * I use TIS version 16 (pretty much the same as version 11 that I used before)

    TIA
     
  2. ChapmanF

    ChapmanF Senior Member

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    Very similar issue just came up in this post over here, only for a Gen 3 in that case. That C1203 is an odd DTC. It has a misleading fortune cookie (no offense intended: we've kind of been using that term for the rather vague short titles that come with DTCs), in that it really does not have anything to do with the ECM. In Gen 2 it pertains to information stored in the skid ECU not matching identification received from the HV ECU. (In Gen 3, the skid ECU stores information about three other modules in the car, but still not the ECM).

    There is not much in the Gen 2 repair manual to do about it. The first step is to check for any DTCs from the HV ECU. If there is any HV ECU condition, after fixing that problem, maybe the skid ECU will again get the information it expects from the HV ECU, and the C1203 will be resolved.

    Otherwise, the manual says to check whether the skid ECU has also reported C1300. That's a self-test failure and means the skid ECU has to be replaced (unless it can be cleared and not come back). But the next step for C1203 without a C1300 is to replace the skid ECU anyway. :shrug:

    I tagged @Elektroingenieur on that other post too, hoping there might be some more information available.
     
  3. smokeGTI

    smokeGTI Member

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    I think I should joining that post instead, thanks for the info's, (y)
     
  4. smokeGTI

    smokeGTI Member

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    **UPDATE** problem SOLVED!!
    As I have searched many info's from google, and was able to locate this instruction,
    It's clearly states that parking brake should be "RELEASED" instead of "APPLIED" as TIS states.
    So I have hook up 12v battery charger to make sure it has sufficient voltage,
    then perform Linear valve offset. It turned out to be succeed !!!
    And codes are automatically cleared!
     
    wheezyglider likes this.
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    I was really, really interested in reading this, since I have a car with similar codes and it could not be corrected. Unfortunately, it has turned into the most aggravating thing in the world due to the huge number of ads that keep popping up and covering the parts of the screen, making it practically impossible. Hate that crap. Hopefully it works better for everyone else.
     
  6. ChapmanF

    ChapmanF Senior Member

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    I do remember it struck me, in one of my first times skimming the manual, that there were two different brake/skid-related learn-something procedures where the only difference between them was whether the parking brake was on or off, and all the other steps (in the without-Techstream version) were identical. So it was clearly using the parking brake switch input to select between two routines. I never remember offhand which one is which; the best I do is remember to make sure I look that part up!
     
  7. tallman

    tallman Junior Member

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    My snap on scanner won't do it unless park brake is set ?.?.?
     
  8. ChapmanF

    ChapmanF Senior Member

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    Does the scanner just show you instructions that say "make sure the parking brake is set"? The instructions could be off. Or does it refuse to try the procedure if the brake isn't set? Or does it try the procedure but the procedure fails if the brake isn't set?

    I'm pretty sure the linear solenoid offset procedure is the one where the car wants the brake released. It kinda makes sense, as having the parking brake applied changes the pressure response of the rear brakes ('cause they're mechanically applied), which affects the pressures the ECU is trying to learn.