Bought the van used last year. Previous owner said mechanic could not diagnose the issue. On slight curves similar to on-ramps while accelerating the Vehicle stability control (VSC) will engage unexpectedly, sound an alarm and jerk the steering wheel. Some times to the point of pulling the vehicle out of its lane. Road speed is decreased dramatically as it feels as though the ABS is engaging. This has happened to me at least half a dozen times since June 2023. The condition will continue for maybe five or ten seconds until the wheel is straightened and speed reduced. Searching the Internet seems it's a fairly common problem. The fix might be to replace the steering rack or disable the VSC system. It's reported by those experiencing the issue get little to no help from the dealerships which strikes me as quite strange... From what I've read it seems to affect 2004-2009 Siennas

- Clarence, NY, USA

Vehicle traction control system will activate around a curve and break the vehicle while the traction control warning system activates. Breaking around a curve in a wet road situation can be very risky. Numerous other Toyota owners have filed similar complaints.

- Indianapolis, IN, USA

The vehicle stability control system randomly engages and activates the brakes without cause. This can happen on a gentle curve going under the speed limit. It is very scary and I am afraid it is going to cause an accident. Internet research shows many owners with this issue and no information on the cause or a fix

- Lovettsville, VA, USA

Slip light indicator comes on and alarm goes off, while anti-lock brakes engage. This is happening while I'm driving on the highway never in the city. The car starts pulling to the right sometimes almost pulling me off the road. The road conditions are completely normal and dry no gravel in it no reason whatsoever for the anti-lock brakes to start engaging. When this first started happening it only happens on curves while I was driving approximately 35 mph. After a couple of months it started happening also while I was driving approximately 70 miles an hour going straight on a dry road. It almost pulled me off into a ditch. The steering is affected I can barely steer but I have managed to keep the car on the road. This is now happening more frequently. I was almost pulled into another car to my right once. At first it was only every couple of months but now I had it happen twice in about a hundred mile trip. There's no way I can get a mechanic to have this happen because you can't predict when it will happen and many miles it won't happen. It is very very dangerous and I'm afraid to take my Toyota sienna on the highway now. After researching it I have found that many people are having this trouble with their Toyota Sienna's there needs to be a recall or a repair. Apparently Toyota mechanics have replaced all kinds of things in the Sienna's but nothing has fixed the problem.

- Searcy, AR, USA

Vehicle Trac Control/ABS system engages periodically especially on winding roads between speeds of 30-60mph. Trac Control alarm goes off and vehicle pumps brakes automatically, then resolves. This is extremely dangerous especially when roads are wet/icy or when being followed too closely by another vehicle. Tried replacing front right wheel speed sensor but problem persists. Research shows this is a chronic problem with Sienna vans and needs to be repaired or guidance provided by Toyota on how to resolve before someone gets hurt. Please help!

- Felton, CA, USA

I've had multiple instances of driving along at varying speeds ranging from 35 to 65 mph, where the traction control kicked in abruptly, the slip indicator lights come on along with the traction control light on the dashboard, a beeping sound occurs, and the van brakes suddenly on its own. This has happened on dry pavement without any reason for traction control to kick in whether I'm driving straight or going around a curve. It is very dangerous and I've stopped driving the vehicle since I often drive with my 3 young children and I fear for our safety.

- Mountain House, CA, USA

When driving on a curve traveling about 30 to 45 MPH. The traction control engages in perfectly dry road conditions. It automatically brakes and jerks the car one way or the other. Very dangerous, especially since you're traveling on a curve when it most often happens and you basically lose your ability to control the vehicle. I won't even let my wife drive the car. There's no known remedy for this problem and I can't even sell the car.

- Arlington, WA, USA

Vehicle shut off when going over the drain pipe I rolled it into a gas station turned it on and off switched gears and it started to roll back on drive I tried to move the gears and turned off the the vehicle after ward no gear worked.

- San Antonio , TX, USA

VCS lights activate, alarm sounds and auto breaking while traveling at posted speeds while going around curved roads. Creates loss of control. Dealer has no remedy, mechanic has no remedy. Many similar issues found on on-line forums.

- Tucson, AZ, USA

With no warning ABS will lock up and cause van to violently swerve to the right while driving. Sometimes once, other times several times in a row. Only lasts for a few seconds. But long enough to cause an accident. Terrifying to loose complete control of your vehicle until it decides to give you control again. Several trips to different Toyota dealers as well no less than 5 different mechanics and no one has any idea what causes it. However the Toyota dealers were all very familiar with the issue but had no idea how to fix it. This has been going on for 18 months. The internet is full of people trying to solve the same issue in 2004-2010 Toyota's in all models. Please help!

- Shepherdsville, KY, USA

When cornering the vans stability control activated without warning and modulates the ABS brakes and beeps and becomes very unstable. My wife and I have both experienced this and fear it will cause a car accident. It is not happening all the time but makes me worry every time we drive a windy road. We had the Toyota zero point calibration done, have replaced wheel bearings and done an alignment which have not changed it at all. It typically happens on curvy roads between 25 and 65 mph.

- Littleton, CO, USA

About a year ago the slip indicator light (car with swervy lines) started coming on intermittently and without warning while turning on highways or roads in dry conditions without any risk of tires slipping. The ABS activates without warning and the vehicle slows down on its own. The situation is very dangerous. No known fix from Toyota.

- Charleston, WV, USA

The contact owns a 2006 Toyota Sienna. The contact stated while driving approximately 35 mph, the vehicle stalled, causing the contact to lose control for a short while. The contact stated that the traction control warning light was illuminated. The vehicle was driven to his destination. The contact attempted to call big island Toyota kailua-kona (74-5504 kaiwi St, kailua-kona, hi 96740; (808) 329-8517) where a voicemail was left. The vehicle was not diagnosed nor repaired. The manufacturer was informed of the failure. The failure mileage was approximately 77,400.

- Naalehu, HI, USA

Traction control warning sounds and vehicle auto brakes - hard. Conditions were clear. Often this happens while the van is in a curve. Speeds vary from 30S to 70S (on the interstate). This creates a very unsafe situation.

- Russellville, AR, USA

The contact owns a 2006 Toyota Sienna. The contact stated that while going around a curve, the vehicle independently slowed abruptly without the brake pedal being depressed. The traction control warning light was illuminated. The dealer colonial Toyota (2600 w pike rd, Indiana, pa 15701, (724) 471-4287) suggested that the issue may be due to a broken wire or a dirty sensor. It was suggested that the vehicle needed to be diagnosed. The contact took the vehicle to an independent mechanic and was informed that the front and rear wheel hubs needed to be replaced. The repairs were completed however, the failure recurred. The vehicle was taken back to the same independent mechanic replaced and the speed sensors were replaced however, the failure recurred. The manufacturer was made aware of the failure. The contact was informed that the vehicle was not covered under warranty or recall. The failure mileage was unknown.

- Arcadia, PA, USA

The slip indicator light (car with swerve lines) started coming on intermittently while turning on highways etc. (but not when any risk of tire slipping). Then vsc light also came on and alarm sometimes sounded. Visit to our own mechanic, no problems found. In the last 2 years the ABS system has activated (daily) it unexpectedly applies the brakes while in motion. It is on specific types of curve and while driving at least 30mph, but has done at 35, 55, 70 mph, on slight or medium turns (not real sharp turns), going uphill or downhill and left or right. Took my mechanic for a ride with the diagnostic computer hooked up, it did the ABS braking, warning light, and beeping 5 times but computer showed no codes. Suggested resetting yaw which we did, it did not help. Suggested calling Toyota, they were no help, said they had never heard of that problem and my mechanic probably did not know how to read the computer. When ABS activates it's very dangerous - thinking about deactivating entire vsc system. I believe the rack and pinion may play a role, there are rattle and bump sounds, perhaps a loose suspension is the culprit, that is our next option. I have already replaced struts, front wheel bearings, all new tires, had it aligned, did new brake pads, and rotors. Absolutely fed up with this problem!

- Wentzville, MO, USA

Traction control activates on dry pavement at random speeds causing vehicle ABS system to brake automatically. This happens on gradual curves taken at 30-45 mph causing the vehicle to pull when ABS activated.

- Sandy Springs, GA, USA

When I drive highways that curve my traction control turns on a nearly causes me to wreck! it's terrifying and it's only a matter of time until it causes an accident.

- Aptos, CA, USA

When driving at speeds of 38 mph or more and turning the steering wheel/tires, the vsc warning alarm will go off. When this happens, the cars automatically brakes. This happens when there are no problems with the driving conditions. The severity of the braking and length of alarm vary. It is especially problematic on tight turns. It does not matter whether you are going uphill, downhill, or turning on a flat road. We do not know what is causing this unsafe issue. We have tried turning off the trac. It made no difference.

- Cassel, CA, USA

The tcs is malfunctioning, causing the brakes to lock up. I.e.-going 35mph, in a wide curve, the steering "jerked" side to side as the van lost traction and then came to a full stop as the brakes kicked in. The traction control alarm and dash light came on during the event, but then went off as soon as the brakes released. This has been on-going for 3 weeks, but the most recent was today.

- Leicester, NC, USA