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Traction control light comes on-slows car down to 20 MPH, Fix?

Discussion in 'Gen 2 Prius Main Forum' started by PriusDadNoob, Apr 29, 2023.

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  1. PriusDadNoob

    PriusDadNoob Junior Member

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    I got hit on my front left wheel. Had to replace strut, control arm, ball joint, outer and inner tie rod, wheel bearing and sway bar link. I've got it back together but now the car will not go over 34 MPH because the traction control (yellow image of car slipping) light comes on and slows me down to around 25 MPH. ONLY that light is on, no codes stored that I can see. It goes away once I go under 25 MPH.

    I've cleaned the wheel speed sensor, tested its resistance (1500 OHMS) and so I think it is good. The little hole in the ring/shield that is on the outermost part of the axle is lined with with the wheel speed sensor hole so that's not it. (I made sure of that when I replaced the wheel bearing)

    I have NOT replaced the axle, so I guess there is a chance that is bad. Ideas? Opinions? You all have never let me down! (the black thing in the photo was broken during the accident, it sits near the front of the car, under the fender. I glued it back in place but I'm not sure what it is or if it could be related!)
     

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    #1 PriusDadNoob, Apr 29, 2023
  2. PriusDadNoob

    PriusDadNoob Junior Member

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    Black thing in photo appears to be a door buzzer. Finally Googled the right series of numbers from the photo!

    Still not sure what the issue is.
     
    #2 PriusDadNoob, Apr 29, 2023
  3. Tombukt2

    Tombukt2 Senior Member

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    It would seem to me maybe you need to at least check both of the front wheel sensor wiring making sure they're all plugged up clean I think if you use an ohmmeter and you pick up the given side and turn the wheel You should be able to count the beats on your multimeter according to the amount of cut outs passed by the sensor . Or something similar to that seems to me the car is being told to put that on the traction control that is because it's not seeing something which is why you don't have a code. Or it's really seeing something and activating traction control completely and doesn't need to I've never seen that happen on one of these every time I see traction control I'm losing traction and can feel it right underneath my car with me in it so for it to be activating and nothing going on sounds like some sensor is not being sensed or not even plugged up or in the mix at all.
     
    #3 Tombukt2, Apr 29, 2023
  4. TMR-JWAP

    TMR-JWAP Senior Member

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    If you don't have it, try to get TechStream, You can monitor each wheel speed sensor to see what they are showing for detected MPH.
    It may not be the one you think.
     
    #4 TMR-JWAP, Apr 29, 2023
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  5. mr_guy_mann

    mr_guy_mann Senior Member

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    Get Techstream or one of the capable scantools in this thread.
    https://priuschat.com/index.php?posts/3290690

    Several can access ABS system data to view wheel speed sensors.

    Might be one tire might have different size. Might be cracked tone ring on the LF axle. Sometimes the WSS mount is off some (corrosion under sensor or damaged screw)- but usually that causes "false" ABS activation on braking.

    Posted via the PriusChat mobile app.
     
    #5 mr_guy_mann, Apr 30, 2023
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  6. PriusDadNoob

    PriusDadNoob Junior Member

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    Thanks for the advice guys. I did replace the wheel speed sensor and it will now go over 35 MPH. BUT the slipping/traction light still comes on, just at 45 MPH, bummer. But this time it does not stop or slow the car, it just beeps and the light comes on.

    Could this all be due to a poor alignment? After replacing all those parts I definitely need one.

    A simple look at the outside of the axle (the slotted "ring") through the wheel speed sensor hole did not show any issues.. Should I replace the axle anyway? I need to get this thing back on the road.
    .
     
    #6 PriusDadNoob, May 1, 2023
  7. PriusDadNoob

    PriusDadNoob Junior Member

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    Yes I do have techstream, and I could see with the old wheel speed sensor it did not register the speed under 10 MPH. The new WSS seems to show the speed at slower speeds.
     
    #7 PriusDadNoob, May 1, 2023
  8. ChapmanF

    ChapmanF Senior Member

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    I am pretty sure the skid ECU has a "check mode" that the repair manual suggests using after hubs have been changed and so on. In the check mode, you drive around a little bit in a certain pattern, and the ECU looks at all of its sensor signals and holds them to a much stricter standard than it normally does, so it's very likely to flag any issues that might be missed or intermittent in normal operation, and if the whole check mode routine passes, that's a pretty good indication of health.

    At least, I know Gen 1 had such a check mode and Gen 3 does, so I'm guessing Gen 2 does also, but I don't have that repair manual in front of me at the moment.
     
    #8 ChapmanF, May 1, 2023
  9. PriusDadNoob

    PriusDadNoob Junior Member

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    @ChapmanF Thanks for the info, but I cannot find details on the skid control ECU check mode. Do you have any more clues for where to look for directions about how to put it into "check mode"?
     
    #9 PriusDadNoob, May 3, 2023
  10. ChapmanF

    ChapmanF Senior Member

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    It'll be in the Repair Manual:

    Toyota Service Information and Where To Find It | PriusChat

    In the Gen 3 manual, for example, the heading is really SENSOR CHECK USING TEST MODE, and can be entered with a jumper from TS to ground, and it starts the brake warning lights blinking, and then you do nothing for a second, then stomp the brake for 3 seconds, then drive over 28 MPH for several seconds till a light goes out, then stop till a light blinks, then drive in a U turn at about 3 MPH, then stop and park, and a buzzer sounds for 3 seconds if everything went right. You will then have tested all the wheel speed sensors, the acceleration sensor, the master cylinder pressure sensor, and the yaw rate sensor.

    But the procedure in my old Gen 1 was different, and I'm sure the details are different in Gen 2 also. As you can see, you kind of need to be looking in the right repair manual for your model to know the right sequence of things.
     
    #10 ChapmanF, May 3, 2023
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