The vsc traction control system activates on it's own. Driving the van it automatically comes on and brakes the van, dashboard light and beeping noise comes on. Brakes you automatically causing the van to veer to the LEFT. This malfunctioning devise (Slip Indicator Light" ON and grinding noise occurred when driving in different speed from 20 mph to 55 mph. It was continuing on the trip to the local Toyota dealer and the other auto repair garage. They currently have the van and are replacing part after part and the problem still persists. Checked on-line and found many other Toyota Sienna owners who are experiencing the same issues as we are. This is a dangerous safety hazard which can cause an accident. As of today's writing the problem has not been diagnosed by Toyota.

I am joining the ranks of people who will NEVER buy a Toyota again. The response to this problem has been unacceptable from the dealership. It is very dangerous to be traveling at 55-65 miles an hour on a crowded freeway to have the ABS sensors or anti-skid senor kick in radically pulling back the acceleration on the Van (04 Toyota Sienna) and veer to the left or right depending on what kind of curve you are on with loud beeping. This happens when no skid is occurring but usually on a curve or incline.

The dealership acts like they've NEVER heard of the problem before and can't imagine what it could be. I want to know if there is a class action law suit started on this because there are many complaints about this serious issue.

Traction control engaged unexpectedly at any speed on curvy roads, causing loss of balance, a few times dangerous when traffic was heavy. It happened the first time on 07/04/2012 when I was driving at around 60 miles/hour on the twisting road from Santa Cruz to San Jose in California. My wife and two kids were terrified and we almost caused accident. Took to Elk Grove Toyota dealer and they recomended to replace Yaw sensor. Had it replaced at another shop (cost mush less) but the problem came back a few months later. Took the car back to same Toyota dealer for testing and they could not repeat the problem. They found nothing wrong with it. Took it to the shop where the yaw sensor was replaced for testing and they also found nothing wrong with the traction control sensors in my van.

I bought this car new in 2003 and it was good until July 04, 2012! During the last 12 months the traction control unexpectedly engaged around 10 times, always in curvy roads. The last two times were on 07/08/2013 (lasted around 2 seconds, at speed around 10 mile/hour) and on 07/12/2013 (lasted around 5 seconds at speed around 45 miles/hour).

I still drive my van but it's no longer a family car, and only me drive it and for local short trips only. I cannot sell it without informing the prospective buyer of the existing probelm, which means there is no way I can sell it. My only hope is as more and more 2004 Sienna owners report the same traction control problem, Toyota will fix it, and fix it before fatal accidents occur because of this serious traction control problem.