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VSC sudden activation. 2004 Toyota Sienna.



  • Peter,

    Any update?

    2004 Siena owner with vsc problem too!
  • Sorry, I have been traveling and did not respond.
    First, I would like to say I just want my car to work and am not looking for more. I am concerned that some may be fishing for some kind of settlement.

    The Toyota dealer in Lompoc CA at first indicated that the Toyota rep had identified some cases where they stated using run flat tires was the problem. I have run multiple sets (3) of non run flats without problem, so I discount this diagnosis. I did have a case a couple of years ago when the car would apply the ABS when driving at speeds greater than 20 mph or so. At that time I disconnected the ABS relay and drove to the dealer (where I reinstalled it). The dealer said the steering wheel sensor needed calibration. I had never done this and had aligned the wheels frequently, given that I have an AWD which "ate" tires. This corrected the problem for 3 or 4 years.

    The dealer told me that Toyota told them that I needed a new steering rack. It would be $800 with no guarantees. The steering is very good with no wandering and no wheel play. So I have a hard time believing this. I would spend the $$ right away if it would fix it, but do not want to start throw money at this with no diagnosis.

    There are only a few components which are in question.
    1. The ABS wheel sensors (also tells ABS if wheels are locking)
    2, The Steering sensor (needs to be calibrated to the steering shaft)
    3. The yaw sensor (tells if the car is rotating as during a skid)

    That's it! All of these have fault detection built into the car. It nothing shows up as a fault they are most likely working at least to some degree.

    The dealers said they looked at everything, but I do not have the confidence that more was done than plugging in the OBD II.

    1. The ABS sensors can be viewed easily with the wheel off. I need to check the sensor and the splines on the shaft (which others have found can get rust and dirt in them as well). ABS sensor are about $90 each without install.

    2. The steering shaft sensor can be easily re-calibrated through the ODB II connector. There is a Toyota Service Bulletin (TSB) on this and it is doable by a home mechanic.

    3. The yaw sensor appears to be the tough one. No east test and very expensive. If all else fails I my go to a junk yard and see if a swap helps.

    Once the ABS sensors have been checked/replaced/ the steering sensor re calibrated and even the yaw sensor swapped there is little more which can be done.

    In the final analysis this could be a systems issue (yes, I am an engineer). In the case of a systems issue, all the combined sensor tolerances my not be working out. Several parts must all play together for this system to work. If it was not designed correctly the errors stack up up and the system fails to function properly even though the individual parts are working to the manufacturers specifications. A classic design failure for many systems.

    We should all be mad as hell! Looking on the National Highway Traffic Safety Admin. site (NHTSA) there are several reports of this same issue. It is CLEARLY a SAFETY ISSUE (and this on what was a $35K car)! We also face some really bureaucratic gov policy at the NHTSA. The definition of what gets recalled is vague at best.

    Beyond this there are numerous complaints by people like us listed on line. Toyota indicated they do not recognize what people put in chat rooms, but most of us have gone to the dealer as well. They are clearly aware that this is an issue.

    When I told this to Toyota Motor Sales (I called it in), I was told that there is no recall in place.

    I will work through my "punch list" to see if I can fix this myself, but would really like to escalate this. We would need reference to as many owners who have this problem and the car VINs. Everyone should make certain to file a complaint on the NHTSA site as well as will Toyota Motor Corp. The NHTSA reacts well to consumer pressure and I would go directly as well as through my local political representative.

    Please let me know what everyone else finds.


  • Thanks Peter for the update,

    I will file complaint on NHTSA site and I will be talking to the dealer serv mgr next week. Also, I removed run-flats years ago from my AWD Siena as they chewed them up way too fast.

  • Hello I have this problem too and it is very annoying. I have spent lots of money changing tires to fix it but it did not work. I am prepared to go to toyota to have them fix this I printed the 2 mediafire links for the yaw sensor and zero point calibration. Should I print any other things? I could not find a service report. Also what should I tell them when I get there. Because every time I try, they just change tires and I have to pay, while nothing happens.

  • We brought our van to the dealer, they adjusted some sensors and I am not sure what else. They did not charge me for this cause I spoke with the service manager ahead of time and complained.. I am not confident the issue is fixed but it has not happened to me since that servicing over the last two months.

    We just traded the van in for a new vehicle, so I hope everyone gets their issue resolved with their Sienna.

  • fibber2fibber2 Mid Hudson Valley, NYPosts: 3,743
    I'm sure that they just did the Zero Point Calibration procedure, and all was fixed. If you had no further problems, then they finally did it right! Best of luck with the new vehicle. What did you get?
  • Kids all days finally OVER!
    Got a Lexus IS350...very un-minivanish! :o) bery fun car...

  • wow, thanks for the fast responses. I just want to makes sure my problem is the same as the other ones here. Sometimes in the middle of the road and highway, the car beeps and does a couple brakes. This process takes about 3-5 seconds. Also the light with the car and the curved lined behid it turns on. this is what i mean ght.jpg
    I just wanted to make sure that this is the right place to look at and that i have the same problem as you guys

    thanks again
  • I just bought a used one from private seller !  And it did the same thing , the vsc activated !!! The brakes were on and the engine got slower 

  • Hi Steve. Did you find a cause of the intermittent VSC activation? I too have the exact problem showing up in my 2004 Sienna and am trying to get more information before I take it in to the dealer. Thanks.
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