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Need ABS/VSC/brake/(!) light help, got codes

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by priusrecon, Jan 16, 2023.

  1. priusrecon

    priusrecon Member

    Feb 10, 2015
    Upstate NY
    2006 Prius
    I have had my ABS/VSC/brake/(!) lights on for a bit. The car drives normally, with no gas milage hit. I have 4 wheel braking, but the regen braking no longer works, and the electric motor continues to pull even when I am stopped at a stop light no matter how hard I push the brake petal. My stop light current flow was normally about 1 amp while I was waiting, but now it is around 3.
    Anybody know what this means?

    Techstream gave me this;
    CO210 rear speed sensor circuit RH
    CO215 rear speed sensor circuit LH
    C1236 foreign object is attached on tip of front speed sensor LH (this one has a blue puffy cloud next to it)
    C1343 hydraulic system RR
    UO123 lost communication with yaw rate sensor module
    UO124 lost communication with lateral acceleration sensor module
    UO126 lost communication with steering angle sensor module

    When I drive the car, all 4 wheel speed sensors report the same speed matching the master speed indicated.
    When I was under the car checking voltages, etc, at the wirings, they all seemed fine.

    Was thinking of pulling and changing the wheel speed sensors, but are they really a problem if they properly report the speed when driving?

    Can I try clearing the codes and see if it drives a bit before re-throwing?

    Tombukt2 likes this.
  2. Tombukt2

    Tombukt2 Senior Member

    Nov 29, 2020
    Durham NC
    2009 Prius
    Yes it's your car You can do what you want seems like you're having communication problems I would look at those wheel speed sensors plugs dirt crap around in them something I'm guessing they're original with original hubs It may be getting time when you say the motor runs no matter what you do stepping on the break what motors running You mean the sound of the ABS pump is continuing to make a noise of course it will as long as you're on the brake pedal that's when you're in park and off the brake pedal The pump should run about 20 28 seconds max and then stop and then if you open the door get in the car and touch the brake again you should hear it start to run again and then if you're not on the break you just did that to see when you get off the break that noise should stop when it keeps continuing to make that pumping noise when you're not on the break and you're standing outside the car that's generally some sort of an internal leak in the accumulator and the pump ramps back up to try and minimize that pressure drop which it can't because the accumulator is constantly bleeding down The accumulator supposed to stay under pressure it's a big clue when it doesn't
  3. ChapmanF

    ChapmanF Senior Member

    Mar 30, 2008
    Indiana, USA
    2010 Prius
    You've already noted those codes down here, so you won't be losing much information if you clear them once to see what comes back.

    While you wait for them to come back, you can make some arrangements for access to the repair manual.

    Toyota Service Information and Where To Find It | PriusChat

    It contains troubleshooting steps for all the trouble codes you can have. Keep in mind that no computer in the car is all-knowing and no trouble code actually tells you what has to be fixed. If a trouble code mentions a wheel speed sensor, it's not telling you to go change that wheel speed sensor. It's saying somebody needs to figure out why something is weird about the signal reaching the ECU from that sensor. The troubleshooting steps help with that.

    Sometimes it's helpful to do a search for trouble codes you have, but make sure, when there's a round character in a trouble code, you always type a 0 (digit zero). It is never a letter O. That makes a difference in getting good search results back.
  4. mr_guy_mann

    mr_guy_mann Senior Member

    Sep 3, 2020
    2006 Prius
    The blue icon is (supposed to be) a "snowflake", that shows there is freezeframe data saved for that code. It's a snapshot of data the ecu saved when (or close to when) it set the code. Give it a look.

    Are any codes listed as "active" or "current"?

    Otherwise clear codes and see what resets. That's the one(s) you chase first.

    FYI, the hybrid control ecu will disable regenerative braking for many/most ABS fault codes.

    Posted via the PriusChat mobile app.