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ABS, Brake, Traction Control lights ON

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by yellowpaper, Aug 7, 2021.

  1. yellowpaper

    yellowpaper Junior Member

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    I own a 2012 Toyota Prius (~108k miles) that has the ABS, Brake, and Traction Control dashboard lights ON. The vehicle is not throwing any DTC codes from the ODBII port. I was able to pull the "blink codes", though I don't have the resources to determine what they mean:

    Traction 31, 45
    ARS airbag 32, 51
    Power steering 93
    ABS text 42
    ABS circle icon 47, 66

    So far, I've replaced the clock spring / steering angle sensor (genuine Toyota) and the two front wheel speed sensors, hoping that these relatively inexpensive parts would solve the problem, though I'm just shooting in the dark and the ABS, Brake, and Traction Control lights persist.

    Is there anyone that can help me unpack these "blink codes", and what parts might be responsible? I don't have access to Toyota Techstream. At what point should I give in and take it to the dealer?
     
  2. rjparker

    rjparker Tu Humilde Sirviente

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    I would take it to the dealer and ask if the free ten year customer support program for the brake booster system applies.
     
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  3. ChapmanF

    ChapmanF Senior Member

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    If you can get blink codes, then the scan tool you are using on the OBDII port is probably at fault for not showing you the DTCs. Good work getting the blink codes. The resource to determine what they mean is the Repair Manual, which you have access to in the ways described here. If your time zone is UTC, maybe toyota-tech.eu is the right site? This post explains how to look up the codes.

    Traction (VSC): 31 = C1231 = steering angle sensor circuit; 45 = "note, there are ECB codes".
    Airbag: 32 = B1650 = occupant classification system malfunction; 51 = problem in driver side squib circuit
    ABS: 42 = "note, there are ECB codes"
    ABS circle icon (ECB): 47 = C1247 = stroke sensor malfunction; 66 = C1345 = must learn linear solenoid offset

    Although it seems the steering ECU still has the vestigial ability to blink out codes, it also seems Toyota had discontinued including the blink codes next to its DTCs in the Gen 3 manual, so that one's kind of mysterious until a scan tool can read the DTC.

    The one airbag blink code 51 is a stand-in for one of four DTCs. 51 tells you there is a problem in the driver airbag squib circuit, but if you had a scan tool and the actual DTCs, they would distinguish whether the squib circuit is shorted, or open, or bridged to body ground, or bridged to +12.

    Since the steering angle sensor is attached to the spiral cable and that squib circuit runs through it, I would certainly re-check connections there.

    None of the codes you have implicate the brake system warranty extension.

    It goes without saying that the Repair Manual is also what describes how to follow through on troubleshooting for those codes; the brief information I copied above is only enough to suggest what general areas need to be looked at.
     
    yellowpaper likes this.
  4. yellowpaper

    yellowpaper Junior Member

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    Thank you for helping to steer me in the right direction. With the mention of C1345 "must learn linear solenoid offset", I thought I would try the OBD-II linear solenoid re-learn process by shorting TS (pin 12) + CG (pin 4) terminals. However, the brake light did not flash and there weren't any odd sequence of brake noises. I've did read that if the vehicle didn't need to re-learn the solenoid behavior, that it's normal that nothing special happens. Though, I also read that Zero Point Calibration requires that TS & CG must be connected and disconnected 4 times or more within 8 seconds, which is something I haven't tried yet.

    Regretfully, if that doesn't work, I don't really have the expertise to diagnose further. My next step will be to check Reddit to see if there are any reputable Japanese auto mechanics in Las Vegas.
     
  5. yellowpaper

    yellowpaper Junior Member

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    Resolved at mechanic: reprogramming of yaw/stoke/solenoid ($102) + alignment ($95).
     
  6. robomoto

    robomoto Member

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    I had these same 3 lights come on in my car intermittently, causing loss of regen braking. The first few times I turned off the car then back on and it went away for a while. Then it came on all the time.

    I think I solved mine without spending any money. What I did was after reading this thread, I cleaned and tightened all my wheel speed sensors. For the fronts, I unscrewed the sensors from the hub, cleaned it with a rag and put them back in. They weren't dirty, just a bit dusty. For the rears, I didn't have the right pliers to take the electrical connector off from the hubs' speed sensors so I just wiggled the connection a bunch of times because I could sense some play in there, and pushed them back in tight. I think the problem was dirt, freezing water and grime got inside the connector in this freezing weather messed up the proper electrical contact inside of there.

    This seems to have made the lights go away. I've driven it for about 5 hours without the lights after this. If these lights happen to you, you should try this first. Just try to clean your speed sensors and wiggle them back in tight to ensure a proper connection.

    IDK about the yawsolenoid and what not. My solution might just be temporary.
     
  7. ChapmanF

    ChapmanF Senior Member

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    It is easy to get the trouble codes when these three lights come on, which is how you find out why the brake ECU has put those three lights on. It's approximately useless to base anything on just "had the same 3 lights" because those are the only 3 lights the brake ECU has to alert you to problems with, and it uses them for pretty much all one or two hundred reportable issues.

    If you don't have a scan tool, you can still get the trouble codes using nothing more than a short piece of wire, and counting the blinks of the lights. There are a lot of posts here on PriusChat on how to do that.

    If you retrieve the trouble codes and the ones you get are about wheel speed sensors, then that would give you a good reason to at those sensors, as robomoto has done here.

    If you retrieve the codes and the ones you get are about something else, then you would probably skip fiddling with the wheel sensors so you could spend your time checking out whatever issue is really being reported.
     
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