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Trying to Remember The Cheat Code

Discussion in 'Generation 1 Prius Discussion' started by bopeton, Oct 29, 2011.

  1. bopeton

    bopeton New Member

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    2003 Prius
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    I have a 2003 Prius, and over time, the steering wheel starts to vibrate. After a while, usually in cold weather, it will stop working altogether and the red triangle exclamation light will come on.

    In the past, all that's been needed is to do a cold reset on the ECU (apparently this issue is a software bug in the ECU); I do this by some sort of sequence of starting the car, messing with the gear shift, and I don't remember what else. It doesn't require any sort of scan tool or even opening the hood. I don't feel like getting it towed and such and don't mind just resetting it every ten months.

    Unfortunately I've forgotten the sequence. Does anyone know what I'm talking about and can remind me what to do?
     
    #1 bopeton, Oct 29, 2011
  2. ChapmanF

    ChapmanF Senior Member

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    There's more going on than a software bug: the cause lies in a pair of potentiometers buried in the steering rack that measure how hard you are turning the wheel, which tells the ECU how much help to give. Those potentiometers get dirty and noisy over time. Have you ever turned a volume knob on an old decrepit stereo and heard scratchy sounds from the speakers and sudden random jumps in volume? That's exactly what's happening.

    If it happens enough within a single drive, the steering ECU decides it's had enough, throws the warning light, and stops assisting. That has happened twice to me so far, both on very long drives; apparently the ECU is doing something like counting glitches, and on a long enough drive can count enough to reach the limit. No doubt the drives will get shorter as the problem progresses.

    When my ECU cuts out, all I need to do is turn off the ignition, and it gives me power assist again on the next drive. I have never needed any trickier reset dance. Mine is a 2001, so perhaps they changed something, but ignition off does it for me.

    The problem won't go away until you have the steering rack replaced. Toyota did send a letter over the summer that they will do this for '01-'03 Prii through 2013, with no mileage limit. Not a bad way to stand by the product!

    -Chap
     
    #2 ChapmanF, Oct 31, 2011
  3. bopeton

    bopeton New Member

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    I believe you, since my knowledge of this car is probably least in-depth of any I've owned.

    The last time this happened, I did some funny thing with switching to neutral while holding holding the key in the 'start' position and pumping the break three times... or some crazy thing like that. Everything reset and not only did the lights go away, but the wheel stopped vibrating.

    Could've been coincidence though. I hear it's intermittent.

    So... I called the dealer and explained to them that I was having this problem and I'd like to take advantage of the warranty extension or recall or whatever they're calling it. They didn't know what I was talking about and said they'd get back to me.

    Do you have some sort of item number or other information I can give them to reference the letter you mentioned?

    Thanks!


     
    #3 bopeton, Nov 1, 2011
  4. ChapmanF

    ChapmanF Senior Member

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    I received the letter on 19 July (according to where I posted about it here), in the same envelope as my notification of the pinion nut recall. Unfortunately I don't really see any obvious document number or something on the letter that would precisely identify it.

    Some other posters have received the letter. I asked (in that original post) if the folks who use techinfo regularly had found more information there, but I don't see any replies.

    -Chap
     
    #4 ChapmanF, Nov 3, 2011
  5. Leslie watson

    Leslie watson New Member

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    Location:
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    Vehicle:
    2001 Prius
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    ----UK----
    Hi.
    I am in England and have a 2001 like you.
    The car has been standing for 18 months and now wont start.
    We have tried to charge the battery and once got the ready sign on the dash.
    Can we cheat the ECU to think the battery is fine and 100%.






    Les
     
    #5 Leslie watson, Mar 6, 2019
  6. Brian in Tucson

    Brian in Tucson Active Member

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    No.
     
    #6 Brian in Tucson, Mar 6, 2019
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