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2012 Toyota Prius 4 - ABS, BRAKE, & TRACTION CONTROL Lights on

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Ben G, Oct 1, 2024.

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  1. Ben G

    Ben G Junior Member

    Joined:
    Oct 10, 2017
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    Location:
    New York
    Vehicle:
    2012 Prius
    Model:
    Four
    2012 Toyota Prius 4, 187,200 miles. Leather, Nav system, Bose system.

    I'd like to tell you about my recent experience with this. I was on a 2.5-hour drive home and at some point my ABS, BRAKE, & TRACTION CONTROL lights went on. My brake pedal felt like a manual pedal, a little harder to push down and a longer throw to get braking power. Thank god my brakes were still working. Obviously, I had no traction control or anti-lock brakes. I knew this was a serious situation. I had an OBDLINK LX scanner so I plugged it in. I had to buy the enhanced codes for my car @ 15.00 but I thought it was worth it. It returned c1214, and c1391 codes. C1214 Hydraulic System malfunction & C1391: Abnormal Leak of ACC PRESS. I started doing my research about these.
    I got quotes from 3 local Toyota dealers. I got quotes from a low of 2350.00 to a high of 3350.00. Needless to say I was kind of freaking out, that's just too much of an expense for me right now. There are 2 parts associated with this repair. I had read of one guy who had the same situation, and he took It into a local repair shop and the right rear rotor was leaking. He replaced that and the lights disappeared. I thought I would try that. I took the car to a local Mavis tire repair shop where I had done work before. I explained the situation. I told them my front brakes were done in 202 and I had 115k miles at the time. I thought maybe those front brakes were causing the issue since now I have almost 183k miles on the car, that's 68k on the front pads. The mechanic hooked it up to his OBD scanner and got the same codes as I did. Meanwhile, I told him to replace the front pads and rotors and then clear the codes in the system. Lo and behold, no more lights on the dash and the problem seems to have been fixed. It cost me 430.00 for the repair, a big difference from the numbers I was looking at. There is one thing that still bothers me. The Brake Booster Pump Assembly (Accumulator) still cycles on and off every 8 seconds for 3 seconds at a time. I don't think this is what it's supposed to be doing. So I don't think I am completely out of the woods yet. To be continued...
     
    #1 Ben G, Oct 1, 2024
  2. Brian1954

    Brian1954 Senior Member

    Joined:
    Jan 31, 2021
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    Location:
    South Central PA, USA
    Vehicle:
    2011 Prius
    Model:
    III
    You did not fix the problem by replacing the front brakes. That was money that you did not need to spend at this time. The warning lights will return in very short order.

    You need to get the brake booster/actuator replaced to fix the problem. As you found out from the quotations that you received, it is an expensive fix. If you do not have the money to get the car fixed, you need to stop driving it.
     
    #2 Brian1954, Oct 2, 2024
  3. Ben G

    Ben G Junior Member

    Joined:
    Oct 10, 2017
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    Location:
    New York
    Vehicle:
    2012 Prius
    Model:
    Four
    Well, As you said, the trouble lights(brake, abs, and traction control) came back on about 2 days after I had the brakes done. I needed the front brakes to be done anyway, so it's not a waste. They had 68k on the pads. I forgot to mention that when the lights first came on, I called Toyota to see if they would cover this repair as I received the Customer support program notification in 2019 alerting me to a possible problem with the braking system. It said if my trouble lights were on, Toyota would cover the repair. Well, in 2019 they were NOT on. That program expired in 2021, and then they extended it to say they'd cover the repair for any car up to 10 years in service and/or less than 150k miles(I am past both those markers). I spoke with the guy from Toyota and he said he'd escalate it to the review board. I purposely didn't call Toyota back. I wanted to wait a few days to see if the lights came back and they did. Curiously, I reran the OBD scan yesterday, and I got only the C1391 trouble code, not the C1214 as I did before. So I am about to call Toyota this morning and see what they say......
     
    #3 Ben G, Oct 4, 2024
  4. Lakotaed

    Lakotaed Junior Member

    Joined:
    Apr 20, 2020
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    Location:
    Orange County
    Vehicle:
    2005 Prius
    Model:
    Two
    It’s my experience that excessive brake pedal travel is often monitored—there is some kind of sensor to report to the ABS controller. A combination of thin rotors, severely worn pads, and air in the lines will easily trigger a code C1214. R & R of brake components and bleeding will clear this code if there isn’t a leak. Just get a flashlight and look at each caliper for any sign of wetness before you start buying parts.

    The C1391 is the beginning of the demise of your ABS Unit, it’s a 4 component unit in Gen 2s: accumulator, pump, valve assy, and Controller. It’s split up in the Gen 3, so maybe cheaper to fix.
    I have installed many of the Gen 2 units purchased from eBay and it’s really bad odds that you get a good unit. I would suggest any seller that says the units are rebuilt.

    it’s about 2-3 hours of labor for me—the calibration and bleeding are a long process. It’s messy, and brake fluid will peel off any paint that it touches.

    FYI—the next step in the progression of failure is a complete loss of brakes. You’ve been lucky if you were able to pump up your brakes to stop.

    The tech must have a bidirectional scanner to complete calibration after installation, a little hand-held unit doesn’t have the capability. A shop will charge for a lot of labor, and of course the ABS Unit is expensive too.

    I am a mobile mechanic, I have been doing ABS for a while, so I assume there are others like me in your area. I advertise as a hybrid tech, check Craigslist in your area. Good luck.
     
    #4 Lakotaed, Oct 24, 2024
  5. Prius DIY nut

    Prius DIY nut Member

    Joined:
    Apr 23, 2022
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    Location:
    Ontario, Canada
    Vehicle:
    2012 Prius
    Model:
    Base
    Here is a video on replacing the ABS unit and then running ABS bleeding procedure. My small dongle Thinkdiag bi-directional scanner can do this ABS bleeding with no problem, same messages and actions as in this video with a pro scanner. I did that bleeding procedure to just replace old brake fluid hoping it will prolong my Prius ABS unit lifespan. So If my unit fails, I will attempt the replacement myself.
     
    #5 Prius DIY nut, Oct 29, 2024
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