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ABS/ECB system problems

Discussion in 'Gen 3 Prius Technical Discussion' started by aspiringnobody, Mar 27, 2023.

  1. aspiringnobody

    aspiringnobody Junior Member

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    So, got the dreaded combo of skid, brake, abs and ecb lights last but. Comes and goes on its own (skid light comes on like the traction control or abs is engaging, but only a clicking noise sort of like the noise a starter makes when the battery is dead). No actual slipping is occurring. After I come to a stop and release the pedal the lights come on. Then some time later after making a stop the system will reset.

    Codes are:

    ECB: C1252 (52), C1256 (56), U0073 (94)
    ABS: C0215 (34), C1239 (39)

    Any suggestions? The accumulator pump doesn't seem to be running any more often or any longer than normal. Lights never come on randomly, only when braking, so the left rear sensor doesn't seem to make sense either (if it was really bad shouldn't it fail while at speed?). Pump is probably marginal but there's the CAN bus error so I'm not sure where to start?

    Hoping it's not a bad skid control ecu as the pump is also obviously not long for this earth.

    My Toyota experience went from never a problem to seriously unreliable the second I got 150k miles on it. Not having a good month.
     
    #1 aspiringnobody, Mar 27, 2023
  2. ChapmanF

    ChapmanF Senior Member

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    You've done some good thinking on it, but you could still do worse than following the troubleshooting steps in the repair manual.

    Toyota Service Information and Where To Find It | PriusChat

    I might start with troubleshooting the comm error, because it's kind of iffy trying to get other stuff to work when you know of a comm problem.

    As for the other codes, freeze frames or the live data list could tell you more. It might be helpful to see what the LR speed sensor was reading compared to the others at the time the code was set. Likewise, it might not seem like the pump is running any differently than normal (what's your sense of normal? how long have you had the car?), but the freeze frame might show you a picture you hadn't noticed.
     
    #2 ChapmanF, Mar 27, 2023
  3. aspiringnobody

    aspiringnobody Junior Member

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    I guess I need to get the techstream cable ordered.
     
    #3 aspiringnobody, Mar 27, 2023
  4. aspiringnobody

    aspiringnobody Junior Member

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    Was able to apparently fix this with either the wheel bearing or the new tire I put on.

    I didn't notice until after I had started replacing the wheel bearing that the tire had a slipped/broken belt and a big bulge on the tread. I can imagine how the diameter of the wheel varying would cause speed sensor issues. I also had to replace a brake caliper since the pad was wearing at an angle, so it's possible that just bleeding the brakes made it go away temporarily and it will come back. (Actually I think I needed to replace the bracket but since you get both I changed the caliper also).

    Fingers crossed it was the tire it the bearing/sensor.
     
    #4 aspiringnobody, Mar 30, 2023
  5. ASRDogman

    ASRDogman Senior Member

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    Are you talking about the rear caliper? If so, perhaps the pad was not installed correctly.
    you have to position the puck so the pins on the pad align with the holes in the puck.

     
    #5 ASRDogman, Mar 30, 2023
  6. aspiringnobody

    aspiringnobody Junior Member

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    It was the outside pad. It was doing it last time I did the brakes also. I assumed it was because the slot in the bracket the pads go into was too corroded or something and it was bound up, but cleaning it really well obviously didn't fix it.

    I did check to make sure that the pins slotted into the caliper piston so that's all kosher.
     
    #6 aspiringnobody, Mar 30, 2023
    ASRDogman likes this.
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