Bad combo meter —> linear valve offset fail? hypothetically…

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Phaul80, Jun 18, 2025 at 1:02 PM.

  1. Phaul80

    Phaul80 Junior Member

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    my combo meter is bad and went from intermittent to totally gone while doing this brake work in the driveway over the last week or so. Since the lights blink rapidly during the linear valve offset process, the skid control ecu is sending a signal to the dash. could there be an error between those two ecus that causes my 1345 and 1368 dtc’s?

    i swapped in a ebay abs actuator i got from partsbravo. i also replaced all brake components on the front end - flex hose, calipers, rotors and pads.

    the pads were extremely uneven, and the caliper piston was seized.. even after removal and emptying the fluid via banjo bolt, it took more than a little effort with a caliper piston tool to make it budge, let alone seat itself back in the caliper.

    now here’s the other issue- and maybe more telling. when installed the new brake parts, the wheels moved freely. after the air bleed, the new pads are clamped on the rotors, ie the fluid is not being sent back upstream. thats gotta be the used actuator with a bad valve/solenoid/whatever and im about to rip it out and send it back

    But… hypothetically, could a bad combo meter send errors to the skid ecu becuase the lights arent showing up on the dash?
     
    #1 Phaul80, Jun 18, 2025 at 1:02 PM
  2. Tombukt2

    Tombukt2 Senior Member

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    I don't know I wouldn't put put too much stock on the combination meter clamping my brakes because the skid ECU can't see something or there's miscommunication between ecu's I would think it would refer to some default mode under conditions like said . Not just clamp up and hold . I check that caliper make sure it is releasing when there's no pressure there just to be sure especially anything that I had to wrestle apart
     
    #2 Tombukt2, Jun 18, 2025 at 3:01 PM
  3. dolj

    dolj Senior Member

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    The best idea would be to read the codes. If there were problems with the CM, you would see codes for it.

    C1345 – Linear Solenoid Valve Offset Learning Undone
    C1368 – Linear Solenoid Valve Offset Malfunction

    There are 4 sub-codes for C1345 – 501, 502, 503, and 504 that will tell you for which corner of the car the value of initialization of linear solenoid valve and calibration is not stored

    The C1368 indicates initialization of the linear solenoid valve and calibration is undone.

    It would seem the learning process failed.

    That could implicate the ABS actuator unit as being suspect if the process continually fails to calibrate.
     
    #3 dolj, Jun 18, 2025 at 11:16 PM
  4. Tombukt2

    Tombukt2 Senior Member

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    But these weren't the codes you had initially when you started on this journey I'm guessing. Did you just buy default go and try n lean linear v offset ? Did you clear out what's stored first . But why did you do this just because usuall wen I'm using used part I do not touch that screen at all I til after all bleeding is complete and cars stopping like supposed to more or less . Usually with a used actuator I don't even have to touch that setting . But I also have not cleared or unlearned anything either.
     
    #4 Tombukt2, Jun 19, 2025 at 12:27 AM
  5. Phaul80

    Phaul80 Junior Member

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    @dolj @Tombukt2

    journey is a great way to put it LOL.

    i posted this same question on the Prius subreddit and a commenter there mentioned that during linear valve offset, the parking should be off and that techstream has a typo- ive been pressing the parking brake each time totally unaware of that because thats what the directions say on the techstream software. i just confirmed with the 2005 shop repair manual that theres no mention of using the parking brake. im using a cracked version on a virtual machine so no corrections being made any time soon. lesson learned, but i still need to try this whole process once again before i deem the ebay part is going to be returned.

    ive got a day off today, so im going to

    1. jack up all 4 sides and remove tires
    2. remove piston side of caliper, crack bleeder screw to drain brake fluid and press the pistons back in, then install them back.
    3. abs ecu -> utility -> reset memory
    4. abs ecu -> utility -> ecb -> zero down
    5. abs ecu -> utility -> air bleed -> actuator replacement ie long form
    6. abs ecu -> utility -> tools -> zero point
    7. abs ecu -> utility -> ecb -> linear valve offset WITH NO PARKING BRAKE

    i will say that when using techstream with a laptop, i often have communication drops and have to start over. I have a trickle charger but not a more heavy duty one, so ive had success with the motor running READY for the first half of the air bleed, then ig-on for the 2nd half of the process. also, my laptop is plugged into its charger. Then I’ll do linear valve offset with READY/motor on. I’ll report back in a few hours
     
    #5 Phaul80, Jun 19, 2025 at 11:18 AM
  6. Tombukt2

    Tombukt2 Senior Member

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    I'm confused about how everybody's running their car out of power bleeding the brakes the front needs no power per se. Then when the relays go back in for the rear the powers on for the pump etc . Then you can power the car off while you hook up the laptop wait for the brake menu to come up and all that stuff then power up and run bleed menu 11 min approx . Weak batteries I guess
     
    #6 Tombukt2, Jun 19, 2025 at 11:37 AM
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