help! 2017 removed calipers/pads/cleaned. Restarted got Braking Power Low/ABS system malfunction,etc

Discussion in 'Gen 4 Prius Main Forum' started by DC_2004_Prius, Aug 25, 2025 at 12:33 PM.

  1. DC_2004_Prius

    DC_2004_Prius Member

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    2017 Prius 3 Touring:

    Removed calipers/pads lubed slide pins etc on our Gen 4 2017 three touring prius with radar cruise, etc. in my family that doesn't get driven enough and there as some minor brake rubbing noise, etc.

    Anyway - didn't disconnect the 12V (mistake!) but have done this on my prime successfully and did remember to take the key away out of range so brake actuator/pressure pump wouldn't kick in - but on the 4th wheel (front) got complacent and forgot and approached the car with key in pocket while caliper was off the pads/hanging and pump began to buzz/pressurize - immediately ran away but had to do a little bit of piston compression with a big c clamp (piston didn't come all the way out just a half inch or so of extension). No problem, pushed piston back a bit and put brakes back together - then made my second mistake forgot to pump brakes before starting up - and boom - full dash and beep light up - got the christmas tree of lights/malfunctions. "Braking Power Low Stop in a safe place see owner's manual, antilock brake system malfunction visit your dealer, lane departure alert malfunction visit your dealer, pre-collision system malfunction visit your dealer, braking power low visit your dealer," etc.

    drove it a little in the neighborhood and it's clear there is no regen braking - only pads - which all seem to be working fine as friction brakes only. went back and double checked no wheel/speed/abs sensors were knocked loose or disconnected. brake fluid level looks normal, etc. I guess there's a chance some major component failed coincidentally or I knocked something else loose? during the cleaning/lube job, just before starting it back up but seems doubtful. I'm pretty sure it's just the temporary lowering of pressure due to the piston movement/compression and that I forgot to press the brake pedal a bunch of times before restart - so system "thinks" there is a big loss of braking/fluid pressure.

    long and short my brakes seem mechanically fine and all working but no regen braking is happening - and the major brake system and auto braking system/abs errors that were produced due to the minor piston push out and forgetting to pressurize the system with pedal pumps on re-start - will not go away. and i'm clearly in some kind of "limp mode".

    i pulled negative battery cable (battery up front) left off for hours.
    cleared codes in dr. prius and torque pro app - no dice. "malfunction" major errors persist. limp mode persists.

    (in trying to avoid having to setup a techstream system...)

    can i go out and do some short/low speed "drive cycles " to get the system to scan/learn that all is in fact well and overwrite those error codes?

    i saw the "jumper between first row 4th and send row 5th pins on obd2 port" posts and videos but all seem to be for Gen 3 or earlier prius. I don't want to try that without confirmation that it will clear codes on this 4th gen 2017 prius - don't want to f' something else up obviously.

    Is there anything I can do to clear these errors/go back in time and have the system start up and assess normally - and find that in fact brake system/pressure is fine?. Any other monitoring software that is quick, cheap, don't have to pirate with risk of virus/trojans, etc. and will work with my bluetooth obd2 dongle? Can Advance Auto or any other store do a quick "clear codes" that will clear these?

    I don't have techstream - and though it might be useful to have for a multi prius family - I don't have time and don't want to do this atm but fear this is what I'll have to do to get this car back to normal. This car is not driven every day so I can be a little patient to get it "back to normal" if there is some safe way to do this.

    Is there anyone in the DC/NOVA area that has techstream and would lend/rent it to me to get in real quick and reset these errors?

    Thanks for any advice/hints on a procedure/jumper/way to get into and reset those system errors. thanks!

    2017 Prius 3 touring.
     
  2. ChapmanF

    ChapmanF Senior Member

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    It's not clear that all is, in fact, well, without knowing what codes you have and what they mean. If a hunch from how things feel while driving could tell everything needed about the health of the brakes, codes would be superfluous.

    If you're clearing them and they're right back again, the car's not convinced all is well.

    The objective shouldn't be to clear codes, but to understand and remedy them.
     
    Brian1954 and Mendel Leisk like this.
  3. Mendel Leisk

    Mendel Leisk MMX GEN III

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    At the risk of getting the hook: someone in a large white house could heed this advice.
     
  4. DC_2004_Prius

    DC_2004_Prius Member

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    thanks for the reply.

    At this moment - yes that is my sole goal - clear these brake failure codes b/c I"m pretty sure they were set erroneously due to not re-pressurizing system before restarting by pressing pedal a number of times first. (all i did was pull calipers/lube slide pins/pad rub points etc. - then reassemble - brakes and everything working without error prior to that with no codes/errors).

    I have not been able to clear them and they have not re-set. (I am asking for help clearing them on this 4th Gen prius as I suspect it is a code set meant to guard against loss of pressure/fluid/major component which I'm pretty sure I don't have) - I put the calipers/pads back the way they were - operating fine with no codes or errors before just some slight rubbing from sitting/rust - but now with slide pins lubed and everything moving properly.

    Yes -it's possible something has coincidentally failed during my removal/re-installation at the moment of re-assembly - but I'm pretty sure it is my failure to re-pressurize by pressing brake pedal multiple times before starting the car back up (system saw low pressure since it had pushed/moved that caliper piston a little bit briefly when I came near with the key).

    Anyway - how can I clear those major codes to see if they do reset? (I suspect they won't.)

    thanks!
     
    #4 DC_2004_Prius, Aug 25, 2025 at 2:14 PM
    Last edited: Aug 25, 2025 at 2:19 PM
  5. ChapmanF

    ChapmanF Senior Member

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    If you had the 12V disconnected for hours, you cleared them; it isn't typical for current codes to be stored in nonvolatile memory (at least in the generations I'm familiar with).

    In gen 3 the C1451 code is kept in nonvolatile memory, making it sort of the oddball exception that proves the rule.