Error msg after front brake job

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by TresK3, Nov 17, 2025 at 11:02 AM.

  1. TresK3

    TresK3 New Member

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    Location:
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    Vehicle:
    2018 Prius
    Model:
    Four
    Yesterday my kid and I replaced the front rotors and pads on their 2016 Prius. They bought the car about 3 months ago and the (used car) dealer said “FYI, the front brakes will need replacing in a bit.” The weather was good, so we figured we’d do the job before winter.

    Pads and rotors actually looked pretty good (5 - 7mm on pads), but we had everything apart and figured we’d proceed. I’ve done disk brakes a dozen times or so and watched a couple of videos to make sure there was nothing unusual to be aware of (nothing was mentioned). The brake job went very smoothly. However… Once everything was back together and we went for a test drive, all kinds of error messages popped up. Mostly, “Brake system not at full function” (or something like that) and “ABS brake error” but also something about “Lane assist not functioning” and (I think) one on adaptive cruise control. The dash looks like a christmas tree with lights and there is a constant beep-beep-beep.

    What on earth could we have done? Not my first brake-rodeo, but it was our first time working on the Prius. The fluid level is a little low, but still above the Min mark. Also, what fluid should we use? I believe DOT 4 for a 2016 model, but can someone confirm that, please.

    Help!
     
  2. TresK3

    TresK3 New Member

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    Location:
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    Vehicle:
    2018 Prius
    Model:
    Four
    That last error message was a “pre-collision warning” system not working, not adaptive cruise control..

    FYI… we also changed one of the back-up light bulbs. It may not have actually been burned out - we had to do a not of jiggling to get the new bulb to light; it’s possible there was an electrical wiring issue. I don’t imagine that’s related, but...