Can Prius Team or anyone with a 2010 confirm the suggestion made here: http://priuschat.com/forums/gen-iii...l-2010-prius-improve-problems.html#post839943 that the 2010 Prius traction control for the first time will brake an individual spinning front wheel to allow the other front wheel to get torque and try to move the car? If true, this should mean that the widespread reported problems of pre-2010 cars getting stuck in some low-traction conditions would be largely solved. I know without snow and ice it may not be obvious to most new owners, but I'd appreciate any observations since the lack of an improved traction control system would be a deal breaker for me as a prospective purchaser. I know many people in cold climates are happy with their cars, but in my situation I can't run the risk of the kinds of winter mobility troubles numerous pre-2010 owners have reported. Thanks for any thoughts.
So the suggestion is put force down on the road from -one- front wheel? You really like to drive into oncoming traffic or the ditch?
Of course that's not how such traction control systems work at all. It's essentially a function of the stability control system, which would never let the car lose control like that. It serves to get you going, with throttle kept very low. Other vehicles, even some Toyotas I believe, operate like this. Without such a system, two wheel drive cars with open differentials, such as the Prius, get stuck if just one front wheel loses traction. And since the Prius (even the recent models) doesn't allow very much wheel spin, that one wheel doesn't get much of a chance to dig itself out. Hence all the reported problems of people getting stuck on uphill grades in snow, gravel, etc. even when other two wheel drive vehicles traverse the same hill with ease.
Great and timely question! We've been trying to track this down recently with our engineering team, as we had been led to believe Gen 3 TRAC was exactly like Gen 2. However, we've just received some good news! They say that Gen 3 TRAC functions much more like other Toyotas, not Gen 2 Prius, in that it does not cut out all torque in a slip condition. It will try to provide adequate torque to maximize friction between the wheel and the road. Now, I haven't driven the car in slippery conditions, so I can't verify this myself. But hopefully some owner will SAFELY provide real-world confirmation soon! Doug Coleman Prius Product Manager Toyota Motor Sales, USA
Thanks, Doug, but that still leaves unanswered the question of whether the revised TRAC system will *brake* an individual spinning front wheel to allow the other front wheel to receive torque from the engine. If not, loss of traction at a single wheel can immobilize the car. If so, both front wheels must completely lose grip to get the car stuck. It's a huge difference, I think, and the New Car Features Manual, according to the original poster I cited, suggests that the new Prius has made this quite significant improvement. Just trying to confirm that. Thanks again.
Well, I've noticed two big improvements so far with respect to vehice traction: 1) My sister-in-law actually made the tires squeal around a corner while test driving it in power mode. In my Gen 2 that NEVER could have happened - it would have illuminated the slippery icon and dropped the torque immediately. 3) Hill climb assist, as described in the manual. I have only been able to partially test it on a steep gravel incline, but it has a distinctly noticible effect - where the wheels seem to turn, albeit slowly, but not stopping like they used to. Remember all the people getting stuck going up icy hills? This is manually activated from a standstill by depressing the break all the way, but it stands to reason that it may be employing a similar kind of behaviour to a limited slip differential, like you're describing. I hypothesize that something is being done to govern the MGs with speed sensors so that it resembles an LSD... I do not know... Dave
I can say that TRAC is much improved in my usage scenarios (dry but rough roads with some light scattered loose gravel). Hard acceleration into a left turn into traffic - I don't get the dangerous torque reduction out of pot holes or gravel like I have experienced in the 2004 (Early Gen II), even though the traction control light was blinking. Between improved traction of new tires and improved TRAC logic, I'd say I'm much happier. I have yet to experience a wet surface scenario though.
Great news. Losing power pulling out onto a busy road was my main gripe with my 2006. Downright scary at times. Another reason I should get a 2010.
Sounds good! I drove my friend's '99 Camry XLE V6 and its TRAC was exactly how I imagined it should work. I see the blinking "Slip Indicator" but the car did not jerk at all. Power was cut smoothly and I still had power to keep moving so it didn't feel like I was a sitting duck when I am I trying to merge into traffic. I hope it's close to that feel/operation.
If it's that bad just get winter tires. I have had Nokian winter tires on all my cars for years. They work great and go through snow and ice like a 4x4. Then take them off for better fuel in the spring. The reason the Traction control comes on is because the wheels are slipping. If you get grippier tires for the snow the traction control won't come on. "All Seasons aren't."
DaveShermata and HTMLSpinner, Thanks very much for your observations. To me they support (but don't confirm) the report that the 2010 TRAC system can brake a spinning drive wheel so the other one can try to move the car. I think what you experienced is what one would expect of such a system under conditions where one drive wheel has sufficient traction to move the car while the other one doesn't. I'd still like to see this report confirmed more directly, but your experiences do set my mind somewhat at ease.
Steve, I am in 100% agreement with you about winter tires and have used them for years here in the Boston area (even on my all wheel drive Audi wagon, since the AWD does nothing to help the car stop and little to help it turn without skidding on snow and ice). I also agree about the Nokians. The problem is that many of the Prius owners who got stuck trying to go up hills in snow or gravel *did* have winter tires, in some cases Nokians, Blizzaks, and other top performers. Even so well equipped, an open-differential car that essentially functions as a one wheel drive vehicle in low-traction conditions—and that won't even allow that one wheel to try to dig itself out by spinning very much—is apparently at risk of becoming immobilized when most other cars can climb the hill.
Steve - that's a good idea for winter. But not so good for gravel/dirt inclines in the other three seasons. A lot of Gen II owners, especially owners of the 2004 and 2005 model years, have reported the cutting of all power on routine gravel/dirt inclines.
I'm not certain if this is your sense of humor or just plain rudeness. Whichever, I wish this sarcasm would stop!:focus:
Too generalized and, certainly not true in my case. I have Goodyear Assurance Triple Treads, just for that reason and, although it does help, it certainly doesn't eliminate the condition totally. My 2005 Prius has forced me to change my driving technique when accelerating in the acceleration lane, when driving up a reasonably steep hill with gravel, snow or ice on it. Once the car stops pulling the only option is to back up a bit and start over.
I just had a phone call from the dealer - he said in the Prius 2010, the TRAC and VSC systems can be deactivated by pressing a button. Can any Gen III owner confirm that?
There is no TRAC/VSC defeat button. Basic traction control is there to protect the transmission as much as it is to help you stay safe.
I don't recall seeing any TRAC OFF button (which is usually the button that Toyota uses. There might be a VSC OFF button on newer cars but I don't remember).
Nope. Enhanced VSC and TRAC are discussed on Owner's Manual pages 245-8. I see no mention of such a button.
