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C1345 Linear Valve Offset Not Learning

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Paul Crutcher, May 30, 2022.

  1. Paul Crutcher

    Paul Crutcher New Member

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    My Prius isn't learning Linear Valve Offset after ABS actuator replacement.

    My symptoms are no flashing ABS light like it said there would be in techstream. The test will complete on the computer, but the car abs lights won't flash while performing the test or flash fast at the completion of the test.

    I've completed a Reset Memory utility prior to the test as well.

    I had previously replaced the ABS actuator with a supposed known good eBay unit. That's risky, I know. I can hear It functioning, but I can't get it to bleed properly due to the c1345 code.

    Other codes present:
    C1203
    C1246
    C1253
    C1345
    C1364

    No codes have a sub code in techstream.

    Any ideas what to do next? Should I assume a bad abs actuator?
     
  2. mr_guy_mann

    mr_guy_mann Senior Member

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    What's the history on this problem? Are all those other codes still present? Were they present before?

    I have read about some not being able to learn the linear solenoid properly with multiple used actuators. Sometimes only a new part will work.

    Posted via the PriusChat mobile app.
     
  3. mech1222

    mech1222 Junior Member

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    your just trying to bleed succesfully? i just bled mine like normal, but disconnected orange plug and 12v aux( had codes to clear anyway).

    \bleed sequence front driver, front passeneger, rear driver, rear passenger, working fine no codes or issues or relearns done. did not connect techstream at all.

    unplugging 12v aux will clear codes also, but will screw your hybrid mileage also until it relearns, if you have a semi bad battery it may never relearn i have heard...not sure on this but what ive read...
     
  4. ChapmanF

    ChapmanF Senior Member

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    The skid ECU will tell you, with a code, when it needs a relearn to be done. Clearing, or unhooking the battery, will not make that code go away. Only doing the relearning will.

    If you have a brake system that isn't demanding a relearn, and you do a brake bleed without Techstream and get away with it (because you don't happen to have any air bubbles in the places you can't bleed that way), that's cool, but a person whose skid ECU is demanding a relearn is not in the same situation.
     
  5. mech1222

    mech1222 Junior Member

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    so the relearn code would be a permanent one then...? only clears when it sees the conditions it wants to see to clear.
    will this light on fail any inspections in any states? or OP will at least be able to drive vehicle if hydraulic side is working correctly?
     
  6. mech1222

    mech1222 Junior Member

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    and a way to get away with it is, if you remove a donor unit from junkyard car, when removing, cut lines with a pair of dikes/linemans in a way so that the lines will be crimped shut to hold the brake fluid in the abs pump/actuator. most yards pull the pumps this way...

    unfortunately a new unit most likely comes dry... a way I do dry units is open/bleed the lines at the pump, all of them in a row few times at least, you will see the air come out, normal two person pump hold bleed procedure. then go to wheels and bleed.

    is there a bleed action from a scantool, techstream or other, that is needed to be done also per toyota specs to correctly bleed system after actuator replacement?
     
  7. ChapmanF

    ChapmanF Senior Member

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    Yes, because there are valves in there that simply are not open when the ECU isn't telling them to be, so if there's any air in those portions of the unit, there isn't any other cleverness that's going to get it out.
     
  8. mr_guy_mann

    mr_guy_mann Senior Member

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    Define "hydraulic side is working CORRECTLY".

    Normal friction brake operation on a Prius involves lots of hydraulics AND electronics. I assume there's a reason why Toyota engineers decided that you have to perform a linear valve relearn after replacing the actuator. I also assume that NOT performing a relearn is going to affect brake operation somehow.

    Posted via the PriusChat mobile app.
     
    Tombukt2 likes this.
  9. Tombukt2

    Tombukt2 Senior Member

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    So it looks like no one solves this very often without a new brand new actuator pretty funny stuff because on my '09 which had all the lights on and all of that nonsense I put a questionable used actuator all lights out didn't bleed with text dream The brakes are spot on I'll let anybody check them out any shop that wants to look at it perfect The car I just worked on is working just like the '09 but I can't get the 1365 and the 1368 to go away for the life of me Regen breaking works reasonably good better than it was and all of that it brakes straight hands off the wheel doesn't pull doesn't float I have not tried to do a full ABS stop or anything like that from like 60 miles an hour I generally don't do much of that but it seems like it'll be fine what does the linear valve do maybe the better question determines what's going to be linear The application of the brakes overall?