ABS, slip, brake system warning lights

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by pk123, Aug 16, 2020.

  1. pk123

    pk123 Junior Member

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    Driving over a rough stretch of road yesterday, all three of these lights suddenly came on, the brakes became spongy, and regenerative braking stopped.

    Car is a 2010 Prius with 162k miles.

    Two things to note: 1.) I replaced the rear wheel bearings (myself) a couple of weeks ago and have since driven ~600 miles mostly without incident. 2.) The one exception is that when going over potholes/bumps and braking simultaneously, on a couple of occasions I felt the brakes lose their bite for a split second before catching again.

    Seems like a number of people have had this issue arise in 3rd gen Prii.

    I followed one recommendation to disconnect the 12V battery for 30 seconds or so, but upon reconnecting, the warning lights came on again.

    Any advice/experience getting this resolved?
     

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  2. Raytheeagle

    Raytheeagle Senior Member

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    Your car is upside down is the first issue:p.

    But I'm all seriousness, have you checked to ensure the connectors are tight and haven't wiggles loose:whistle:.

    I'd check over your recent work and make sure there is nothing lingering from that;).

    Good luck and keep us posted(y).
     
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  3. ChapmanF

    ChapmanF Senior Member

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    Back when you followed the wheel bearing replacement procedure, did you include the step where you run the wheel-speed sensor test?
     
  4. High Mileage

    High Mileage Active Member

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    pk123, As others have suggested I would recheck the connectors for the speed sensors on each rear wheel hub to make sure something did not come loose. It seems very possible that that a connector for the rear ABS sensors came loose as you went over the bumps.
    If the warning lights are still on after disconnecting the battery you may need a proper scanner that can access the ABS system or the Toyota techstream software to scan the ABS system and check for codes.

    pk123 said "The one exception is that when going over potholes/bumps and braking simultaneously, on a couple of occasions I felt the brakes lose their bite for a split second before catching again." I will say that in my time with my Gen3 and Gen4 that the braking system is very sensitive to railroad tracks, potholes and uneven pavement surfaces when braking. I consistently feel the regen braking cut off when braking over these road surfaces, especially when wet.
     
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  5. pk123

    pk123 Junior Member

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    Many thanks for the feedback, everybody.

    I took the Prius to Toyota, where for a wee $150 diagnostic fee they informed me that the code was C0215 - the left rear speed sensor.

    I contacted 1AAuto, where I'd bought the wheel bearing and hub assembly, and they shipped me a new part. Took out the old one and spotted a small crack inside the plastic speed sensor. So it must have indeed been defective.

    After installing the new wheel bearing assembly, the warning lights remained for a couple of minutes--despair!--only to disappear shortly thereafter. Regenerative braking, cruise control, etc. are all back.

    Anybody else had problem with those TRQ parts they sell on 1AAuto?
     
  6. ChapmanF

    ChapmanF Senior Member

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    This seems like a good place to mention again that if one is following the repair manual steps for replacing a wheel bearing, they end with a test of the speed sensor. An actual test, where the ECU is put into an extra-sensitive test mode and the car is driven in a test pattern, and even small problems with the sensor will be caught, before the job is signed off.

    Wheel bearing replacements following that procedure generally don't lead to surprises.
     
  7. ASRDogman

    ASRDogman Senior Member

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    This is the 3rd place for this same problem.
    TRQ USED to be good. Not anymore. I've bought them for several of my cars and others cars.
    I put over 100,000 miles on those.
    My fronts lasted about 35,000 miles. The right rear bearing seemed okay, just the sensor was bad.
    WHY they made such a stupid design is just insane. They should be as easy at the front sensors.
    I only had 9000 miles on the rear. They are supposed to send both bearings for replacement.
    It's just a PAIN to change them, AGAIN! I had to put the old one back in until the new one comes.

    I will probaly just make a trip to autozone and get a (hopefully) better one. At least I won't have to wait
    a week for the new one when/if one goes bad.

    PK123: for $50 or so you could have purchase an OBD reader w/ABS testing. My code was C0210.
    And it came right after I drop of the old bearings to ship back.
    They had sent the rears first, then the front. I was just going to keep them, but that would have been steeling.
    Now I wished I had waited a week or so!

    It's a simple pulse on/off sensor. What test/calibration would it need with a new sensor? NO COMPLAINING!
     
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  8. ChapmanF

    ChapmanF Senior Member

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    For some reason, Toyota thought it would be useful to build a confirmation test mode into the ECU, and to write paragraphs in the repair manual instructing people to use it after changing a wheel bearing. I wasn't in the room where it happened. But I do it after changing bearings. It's not anything hard to do. (It does require access to some straight section of empty street or the like where you can accelerate to around 30 in a straight line without endangering anybody.)
     
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  9. ASRDogman

    ASRDogman Senior Member

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    Well then, I've already done that on 98% of the ones I've done! :)

     
  10. pk123

    pk123 Junior Member

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    Chapman, is this a DIY-able test, and is there a thread detailing how to do it? Sounds like an excellent idea, but I was unaware that it was recommended.
     
  11. ChapmanF

    ChapmanF Senior Member

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    Provided it was in the confirmation-test mode when you did that, then you have indeed completed the bearing-replacement steps.

    I described it briefly for Gen 1 back in the last paragraph of this post. The details can vary a bit between generations, but they're right there in the manual. If you're replacing a bearing and just following the numbered steps, then by the time you come to the end you will have done it. :)
     
  12. pk123

    pk123 Junior Member

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    The journey continues. Last night in the middle of a 250-mile drive, the ABS, slip and brake-system warning lights came back on, and cruise control stopped working. This time, I took ASRDogman's advice and bought a $50 code reader from Autozone. It turned up codes C0210, C0215 and C1238. All apparently indicate problems with the sensor on the TRQ wheel bearings that I purchased three months ago from 1AAuto.com.

    As with the last time the car threw these codes, 1AAuto is offering replacement parts. But I'm done with TRQ. Hate to spend $400 on OEM parts, but that's better than replacing the wheel bearings every two months!
     
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  13. ASRDogman

    ASRDogman Senior Member

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    Ditto!
    I got 30,000 out of the fronts. About 5 on the replacement ones, and the one
    on the left(front) is noisy, and is hotter than the one on the right.
    They send replacements, but return postage is on me. Took over a week to get here.
    PLUSSSS, I don't want to have to replace them every 6 months!
    TRQ USED to be decent. But since they're made in china now, they suck!
    I'll go to autozone and get the timken ones. They lasted about 100,000 miles on my van.

    Trashed Really Quick!

     
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