Prius 3, reset steering angle sensor

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by 4md, May 14, 2018.

  1. 4md

    4md Member

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    Hello,
    Few weeks ago I wrote about slight pulling to the right here. Today I talked to a guy at a local service shop and he told me that he had the same problem with a Subaru with electric steering after alignment. He said to check the angle sensor with the diagnostic tool and if it's not at 0 degrees when the steering is right, it must be reset/re-initialized.
    So, I hook up the Techstream and the "Steering angle sensor" showed 4.5 to 6 degrees when the steering is in straight position (according to my view).
    I looked for the option to reset it, but found only "Torque sensor zero point adjustment" and "Rotation Angle Sensor Initialization". I successfully completed the learning, but nothing is changed, still the "Steering angle sensor" shows 4.5 - 6 degrees deviation.

    According to the documents, to do the "Torque sensor zero point adjustment" and "Rotation Angle Sensor Initialization" correctly, there must be two DTC logged - C1515 and C1525, so the Techstream cleared the calibrations and the errors popped up. After the procedure, they disappeared.

    So, how can the "Steering angle sensor" can be reset? I was looking in the ABS/VSC/TRC - > Utility and EMPS -> Utility sections, but found nothing... Any help how to do it?
     

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  2. jerrymildred

    jerrymildred Senior Member

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  3. 4est

    4est Active Member

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    So just disconnect / reconnect 12v battery
     
  4. jerrymildred

    jerrymildred Senior Member

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    I think so, but be sure the front wheels are straight and your steering wheel is centered at the same time. But I've never done this before, so I can be sure.
     
  5. 4md

    4md Member

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    Found 2 manuals about the procedure after wheel alignment. One is for Tundra, and the other is for Prius 3. Both don't change the "steering angle sensor". Today had the negative terminal disconnected for a minute and after that, the "steering angle sensor" readings didn't change at all.
    It's a mystery for me, on other cars there is an option and everything goes to 0.0, but here this does not happen.

    Is it possible that this "steering angle sensor" be the real angle between the sensor and steering column and it doesn't have to be exactly 0 degrees when straight and every calibration/learning/reset be the adaptation to this value instead actual resetting the sensor... I can't find any other logic behind this :D
     

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  6. jerrymildred

    jerrymildred Senior Member

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    I think I'm out of ideas other than to wonder if there's something wrong with the sensor in the clock spring assembly in the steering wheel.
     
  7. 4md

    4md Member

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    Little bump :)
    Today I did everything again step by step as it is in the manual. Of course, nothing changed. The car still pulls slightly right on the MOST of the roads. There are some that it goes straight and I think I'm going crazy :D

    While looking at the live data, I saw interesting parameter - "zero point of steering angle". It stays at 0.0 degrees after the procedure even if I turn the wheel in 45 degrees angle, for example. After the "wrong" 45-degrees learning, I did a test drive and strangely, there was nothing unusual - no error lights, nothing. Just before turning off the car, I saw that "zero point of steering angle showed something different than 0.0, but after turning it on again it was 0.0 again. I searched a lot, but I can't find anything specific about that parameter. Can it be set/learned manually?
     

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  8. Abarthi

    Abarthi New Member

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    Sensor is not damaged? You found solution?
     
  9. PTOWNPRIUS

    PTOWNPRIUS New Member

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    Just joined the Prius crew. Picked up a 2012 level 5 equipped, last Friday. Dealer put new tires on, but the steering wheel is out of alignment by 5-10deg or maybe one thumb thickness...enough to notice. I asked them to do an alignment, but they said they saw not abnormal wear on the outgoing set of tires. Can I take my Prius to any tire shop for an and alignment or steering wheel centering adjustment? Perhaps the Chevy dealer looked at centering the wheel but are not schooled up on the Prius steering system? Thanks in advance eh.
     
  10. ChapmanF

    ChapmanF Senior Member

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    See if you can find a copy of T-SB-0391-08 (if you don't find one bouncing around the web somewhere, you know you'll find it at techinfo.toyota.com). It covers adjustments to get the steering centered more exactly, depending on how obsessive you are.

    As for the steering angle sensor zero point, I seem to recall reading in the manual somewhere that its zero point is found automagically during driving: whenever the car is moving and the yaw sensor reads zero yaw rate, the car (reasonably) concludes wherever the steering is right now must be the zero angle. :) So the yaw sensor does need to be correctly calibrated, on a known level surface, and there is a procedure for that.

    I think I saw it in action, too, in a Gen 2 I was driving around with Techstream attached for a while. At startup, the steering angle sensor would be reading something nuts like -1150 (with the wheel centered!), but it would become reasonable as soon as I was driving.
     
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