Brake Actuator & Code Reading

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ChaseC, Jun 2, 2021.

  1. ChaseC

    ChaseC Junior Member

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    Sorry, but yes, here is yet another Brake Actuator thread. I have a 2005 Prius with less than 95k miles on it, still pretty much all original. I live in Florida but took the car up to the frigid Midwest two winters ago. One freezing morning during that trip the Brake, (!) ABS VSC combo lit up. Had it checked at a local parts place and no codes came up. The car was driving fine and was far from home. Ended up driving it 16 hours back home a couple days later and had no issues the whole trip. At the time, simply guessed it might've been a low voltage reading in the new Yellow Top battery. I got busy, the weather got hot and humid, and never got around to clearing the lights. Then the pandemic hit and life see-sawed even more.

    A couple months ago, the car started to randomly beep for a few seconds after starting it or after turning it off. Initially, I thought that might be a low battery warning for the key remotes, but replacing the battery did not help, and the beeping has continued to occur randomly for varying intervals. I hooked up my OBD2 reader but the only code it showed was a P0607 code. This likely is related to the HV ECU as the Cruise Control does occasionally start blinking and stop working (apparently that is a memory warning indicator for the HV ECU).

    So one quick question, is there an iOS scanner app that can read the brake codes on its own since I am guessing mine doesn't?

    Yes, I am skeptical that the brake actuator and the HV ECU are both going bad at the same time. And unless someone knows something I don't, I doubt the HV ECU is causing the brake actuator to have pressure issues and run excessively.

    I've called the local Toyota dealer several times for a quote to replace the brake actuator and gotten zero response. Even after talking to the national office of Toyota and being assured the dealer would reach out to me within 24 hours (that was 10 days ago). Several auto shops in town I was referred to flat out refused to replace the brake actuator.

    After three weeks of only driving the car around the neighborhood to keep the battery charged, I'm getting quite annoyed at how difficult it is in this area to get such an otherwise dependable car worked on. This is the first repair the car has needed since buying it three years ago. Needless to say, I am frustrated right now.

    And no, I don't have the skills or patience anymore to do the repair myself, nor a Windows computer and the Toyota Techstream software.
     
  2. jessiejosco

    jessiejosco Member

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    The Blue Driver reads and resets Prius brake codes. I had all the brake warnings come on 4 years ago twice on really cold damp winter days. The code was for the accumulator pressure that I think is the typical failure. I reset the codes with Blue Driver both times and was preparing to source a good used brake actuator, but the lights have never come back on. I have never had any functional signs of brake failure, even on cold winter days since. So my experience is that the actuator can throw false codes in really cold weather.
     
  3. TMR-JWAP

    TMR-JWAP Senior Member

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    The real issue you may have is whether your code reader is truly speaking Prius language and giving an accurate diagnosis. If it's not, you're chasing your tail. With this being an engine management code and not a Hybrid code, the chances of it being accurate are better than what we usually see described. If we assume it is accurate, the Toyota Repair manual states that for a P0607 the resolution is to replace the ecm. No ands if or buts, that is the solution. Not the HV ECU, the ECM.

    Now, prior to me doing that, I would 100% ensure the 12v battery was healthy and that all related plugs and sockets were fully engaged, maybe even unplugging and re-plugging them a couple times to ensure good connections are present.

    How often is the accumulator pump running?

    From the repair manual:

    MONITOR DESCRIPTION The ECM continuously monitors its internal memory status, internal circuits, and output signals to the throttle actuator. This self-check ensures that the ECM is functioning properly. If any malfunction is detected, the ECM will set the appropriate DTC and illuminate the MIL. The ECM memory status is diagnosed by internal "mirroring" of the main CPU and the sub CPU to detect random access memory (RAM) errors. The two CPUs also perform continuous mutual monitoring. The ECM sets a DTC if: 1) output from the 2 CPUs are different and deviate from the standards, 2) the signals to the throttle actuator deviate from the standards, 3) malfunction is found in the throttle actuator supply voltage, and 4) any other ECM malfunction is found.
     
    #3 TMR-JWAP, Jun 2, 2021
    Last edited: Jun 2, 2021
  4. ChapmanF

    ChapmanF Senior Member

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    Rather than calling them "false" codes, it's probably safer to say that they meant what they meant, and their detection conditions haven't been met again since. Do you happen to remember what code it was? They have quite specific detection conditions described in the repair manual. If those lights ever do come back, my advice would be to note down exactly what the codes are, and exactly what the repair manual says the detection conditions are for those codes. Then it's often pretty straightforward to figure out why they were set.
     
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    and....I'll have to dig through some resources, but I'm not confident about this:

    randomly beep for a few seconds is failure of the accumulator system. The brake system usually emits a constant annoying tone and you get nice dash lights...have you verified the 12v system is healthy?
     
  6. mr_guy_mann

    mr_guy_mann Senior Member

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    If you don't bring the car in for them to diagnose, most shops will not bother with over the phone quotes. They aren't going to spend time on what they perceive to be "price shoppers".

    Or, if they perform the repair that you requested, but that doesn't fix the problem (because no testing was done) now they have to deal with an upset customer.

    IDK of any apple specific scantool that has any capabilty close to Techstream. I suppose if you were determined you could run a Virtual (windows) Machine on a macbook and install an amazon or ebay mini VCI cable with bootleg techstream.
    Posted via the PriusChat mobile app.
     
  7. ChaseC

    ChaseC Junior Member

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    I think this video should sum up the answer to that question pretty well. Sounds like it is running most of the time to me, with only a few seconds break in between.

     
  8. ChaseC

    ChaseC Junior Member

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    I did go ahead and get OBD Fusion and the Enhanced Diagnostics Pack for the 2005 Prius. I was finally able to read the diagnostics codes for the ABS system, and even reset them, although, the dash lights still remain on. Yes, I still need to disconnect the battery and check the connections, although being a less than 3-year-old Yellow Top I would think all is fine back there.

    No surprise, but the code scanner came back with C1256, C1343 and C1391.
     
    #8 ChaseC, Jun 7, 2021
    Last edited: Jun 7, 2021
  9. ChaseC

    ChaseC Junior Member

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    oops...why can't i delete this one reply? lol
     
    #9 ChaseC, Jun 7, 2021
    Last edited: Jun 7, 2021
  10. ChaseC

    ChaseC Junior Member

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    My biggest problem is that when I call around and ask local repair shops if they'll even do this kind of work on a Prius, their response is a resounding NO. And their only recommendation for whom might is the local Toyota dealer who actually seems to hate servicing these cars based on my prior experiences.
     
  11. ChaseC

    ChaseC Junior Member

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    UPDATE: Local Toyota dealer here in Pensacola, Fla. was nothing but a PITA and the only local shop willing to replace the brake actuator quoted me $2800. Ended up ordering the part online for $1200 from a Toyota dealer in Mobile, Ala. and had their service dept. do the replacement. Ended up having the front brakes redone, back brakes cleaned and parking brake adjusted, plus the drive belt replaced. All in was right around $2500 for everything. Lights are off. Actuator is quiet. Gas mileage has improved a few mpg too.
     
    #11 ChaseC, Aug 10, 2021
    Last edited: Aug 10, 2021
  12. ChapmanF

    ChapmanF Senior Member

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    o_O
     
  13. ChaseC

    ChaseC Junior Member

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    Oops, I meant the "drive belt" which I assume is what most of us call the serpentine belt.
     
  14. TMR-JWAP

    TMR-JWAP Senior Member

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    With a stretch of the imagination we can still call it a timing belt...it just controls the timing of the water pump to ensure it spins when the engine is spinning. Sounds like timing to me!

    Although $2500 is a bitter pill to swallow, you're likely better off. Considering the crazy prices right now, at least you know your car history and can take some comfort that one of the most common big repairs is out of the way.
     
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