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Toyota Prius - Traction Control vs Vehicle Stability Control



  • Good snow or all-season tires make a huge difference. Also, throttle control is important.

    Driving our '07 on slick roads for the first time at the beginning of winter felt pretty skittery. After some reaearch, we got Les Schwab "Observe" snow tires. They aren't studded but are supposed to act like studded and are relatively quiet. (Les Schwab is a western US dealer).

    In practice stops and cornering on very icy roads, they are confidence-inspiring. Also, no problem on mountain passes as long as the snow's not too deep.
    Putting on snow tires cost 4-5 mpg, but easily worth it because the car feels more like a Subie with studs (my previous winter car).

    Our driveway is 3/4 mile long, steep, with a couple of tight turns. With the factory tires, my '07 Prius lost traction in 1" of wet, new snow. With snow tires, it climbs quite well. Like any car, when it starts to slip, backing off very slightly helps to get the grip back.

    YMMV, but I've found the biggest problem with slick stuff (snow, rain or gravel) is that the Prius has a lot of torque and the traction control system doesn't manage it well if you just stomp on the gas.
  • andyuandyu Posts: 3
    We have a 2006 Prius with the GY (#1) package. It is very dangerous to drive in snow, which we have a lot of in Wisconsin because it cuts power to the wheels as soon as any slippage is encountered. That may be ok in the rain, but when driving in several inches of snow, there is ALWAYS slippage. Our old Chevy Cavalier gets around in the snow just fine. You just get on the gas and those front wheels just start chewing their way through the snow. In the same scenario with the Prius, you get on the gas and it dies leaving you helplessly waiting for someone to slam into you and kill you. It is not a fit car to drive in snow. If no one has been killed yet, they will be. This is VERY dangerous. BTW - Toyota says that's how it is supposed to work and refuses to do anything about it. They're going to regret that when the lawsuits start. Deliberately engineering such a dangerous design makes them fully culpable. It's inexcusable.
  • wwestwwest Posts: 10,706
    The secret to driving ANY car on the slippery stuff, especially FWD it seems, is learning to feather the throttle YOURSELF just up the point of losing roadbed traction and not beyond. Once TRAC kicks in it will not nearly have the finesse you could use were you to bother to take the time to learn.

    Use TRAC as an indication of conditions, not as something to rely on as help in those conditions, its actions are far to ROUGH-EDGED.
  • I HEAR YA MAN!!! I literally called my dealer today and told them the same thing that you just wrote about. The Traction Control on the Toyota Prius is very dangerous indeed! I live in NW Minn. where snow covered and icy roads are the norm in the winter. I'll give an example of a near death experience I've had in my 2008 Prius. One day while driving home on the split 4 lane highway that leads to my house I had to get into the turning lane to cross the other side of the highway. A car was coming at me about 1/4 mile away as I began to pull out from the median crossing. Since the turning lane and median were icy, as usual, the Traction Control kicked in which killed power to the wheels, as the other car was coming at me at 65-70 mph. Well, not only was it icy in the turning lane and median crossing but it was also icy crossing the highway. Needless to say, if the other car hadn't slammed on it's brakes to slow down for the idiot driving the Prius (THAT WAS ME) who was stopped in the middle of the road since my Traction Control wouldn't allow my Prius to move, I'd be deader than a doorknob! I have been stuck with my Prius 4 times. The deepest snow was 5 inches on a flat gravel road, and the least amount of snow was literally 1/2 inch of snow with packed and ice snow below it! THAT'S RIGHT! I WAS STUCK IN 1/2 INCH OF SNOW IN MY 2008 TOYOTA PRIUS! BUY 'EM WHILE THEY'RE HOT! OH DON'T TELL ME I DON'T KNOW HOW TO DRIVE! The car that sits next to my Prius has 921 horse power and pulls a low 10 second 1/4 mile! Did I mention that my Prius gets great gas mileage?
  • andyuandyu Posts: 3
    That's exactly what I'm talking about. I've had some close calls too. If I or my wife doesn't get killed, I'll cause someone else too as they try to avoid hitting me. I always leave LOTS of room if I'm in the Prius before pulling out into traffic in snow, even to the point where people behind me are honking and I still end up in close calls. People who were behind me waiting to cross an intersection have gone around me and passed me in disgust before I could get across.

    I also have a GMC Sierra 2500HD Duramax Diesel 4x4 with locking differentials. Now that's what you want to be in in the snow. I want my wife to drive the truck all winter, but she won't do it unless the weather is really bad because she says it too big and too hard to park, so she's frequently in the prius, which scares me. Saving a few extra bucks on fuel just isn't worth it.

    I'll have to sell it if Toyota doesn't come out with some new programming for the TRAC before next winter. It's a great little car in every other way, but this is just too dangerous. It makes no difference whether you stomp on it or gently feather it, or anything else in between, believe me, I've tried and the bottom line is it just doesn't go like it should. It's scary.

    My friend has a Highlander Hybrid 4x4 and gets around just great in the snow. I wonder how the Camry Hybrid does? Is it just the Prius's that are so badly engineered? Does anyone know how the Civic Hybrid does?
  • wwestwwest Posts: 10,706
    You know what...??!!

    Traction on ice or well packed snow requires a huge tread contact CSA and WEIGHT...!

    The Prius has neither...!!

    I wouldn't drive a Prius in adverse roadbed conditions, and if I was forced to, not without tire chains.

    And yes, I know, very well, tire chains on only the front of a FWD vehicle can turn hazardous instantly. So drive slow, VERY slow.
  • Guess what?! My wife has a 2008 Toyota Camry Hybrid and it has the same dangerous problems with Traction Control. She wants her 2006 Pilot back and I want my 2002 Camry back!
  • chadxchadx Posts: 153
    Has anyone that has reported the touchy traction control issues had their dealers do a software upgrade as outlined in previous posts? I'm curious if that has helped since some report the '07 and later Prius isn't having as much trouble with this issue and allows for a bit more wheel spin.

    On a side note, this can be an issue with any type of car. Some traction controls interfere more than others. We had a rental vehicle, on vacation one time, and that Buick flat out stopped and wouldn't even put any power to the wheels with the slightest amount of wheel spin on snow and ice.

    As always, tire selection and driving technique make the biggest different, but and overly-aggressive traction control system can be a real pain. Some amount of wheel spin allowance can be a good thing in many situations. I regularly turn off the traction control on my wifes car (rear wheel drive and manual tranny) in snowy conditions. That being said, simply putting a couple bags of sand over the rear axle made a huge difference. Not an option with a front wheel drive, but the engine is already weighting the drive axle (the main reason front wheel drives have a traction advantage in snow).

    The stock tires on the Prius are built for mileage, not traction/permorance. Moving to a snow tire (such as Blizzak) would resolve winter traction issues in all but the most extreme situations. If one isn't willing to go to a dedicated snow tire (and the associated second set of wheels and the twice-yearly swaps), find a good all-season with the best snow rating you can find. That, too, will make a huge difference over the stock tires and completely change the personality of the car in those conditions, plus you don't have to swap them in the summertime.
  • chadxchadx Posts: 153
    Question about the details of the Prius traction control cut-out...Does it behave like other traction control systems where, if you immediatly let off, you can lightly feather the throttle and immediately make an attempt at accelrating again? Or is there some few second delay, unlike a non-hybrid system? Such as, it will absolutely not try and turn the driving wheels at all for a second or two?
  • wwestwwest Posts: 10,706
    The traction control firmware in a FWD is intentionally more aggressive, "intrusive" than a RWD or R/AWD and even F/AWD. That's because loss of traction at the front can too quickly result in loss of directional control. Whereas with loss of traction at the rear you still have "command" of the stearage.

    And remember that those electric motors have absolutely "stellar" low end, low speed, TORQUE. Perhaps you need a "snow" mode.
  • I told my dealer the problems that we were having with the Traction Control on my Prius and on my wife's Camry Hybrid. He told me to buy some snow tires. And the reason that the hybrids don't come with snow tires on them in the northern portions of the U.S. is that snow tires greatly reduce the MPG. I plan on getting snow tires for my Prius within a few weeks. I will post the results.
  • In response to all the Prius complaints about winter traction problems I can honestly say that I have never had the problems that I am reading in this forum.I have been driving my Prius for 5 winters now including last years record snowfall here in Wisconsin.I find this vehicle to be excellent in the snow and I also believe it has a lot to do with how you drive them.Too much power to wheels will make them spin and traction control aids in this.I have also never seen a Prius stuck in snow as many of you have claimed.There are a lot of wrong things to do in winter driving and between my Prius and me we try to eliminate them all.Wouldn't own anything but a Prius.
  • My Prius is great in the winter...I suspect that numerous UAW / US Autocompanies people submit false reports to tarnish the Prius image !
  • andyuandyu Posts: 3
    I have a 2006 Prius and it's terrible in snow. It's a great car, but the traction control is too aggressive. Is that so hard to admit? It's a software problem and probably only affects some models. Of course... UAW members could be posting these "my prius is great in winter" messages to tarnish the image of Prius drivers by making them sound brainwashed...
    I love my Prius, but when a blizzard is on, I'm going to be driving my GMC Sierra 2500HD 4x4 Duramax Diesel and while I'm doing it I may even stop to pull out some of the stuck Prius's. ;)
  • I just had my first real experience driving my '06 Prius in snow. (I think I've been in snow a little since I've had it, but not much.) I suspect a lot of it is that the all-season tires I have do very well in snow, but I have had no real problem.

    I did have one issue with the traction control, but it was in a situation that I didn't entirely expect to make it through anyway. Climbing a rather steep hill, I got half way up when traction became such an issue that the power cut out completely leaving me sliding backwards a bit. I think I might have had a chance without traction control, but I can't say for sure. Anyway, I was able to back up the rest of the hill without a problem.

    It definitely does prevent much wheel spin. For a better description, when the wheels spin, the power gets cut until the spinning stops. At that point, if you are too aggressive, you can quickly spin them a bit more and again the power cuts out. I think it completely cut out when I started sliding backwards. This might be a bug in the software, and this could have been more dangerous if I had been somewhere where I could have had someone behind me.

    So I guess, overall, I think tires probably make the biggest difference. Maybe they're just telling drivers that they need different tires if they're driving in snow.
  • I have to echo several of the posts here: I live in the mountains, have for nearly a decade, very little here is flat and in winter snow and ice are common. My wife and I love our 06 Prius (so far); but we were coming home last winter on clear road when it began to flake a mile from our house. It may have been that I was in a hurry to get home, but I expected the same kind of traction from the Prius I'd get in any 2WD. Not so. We lost all power going up a short hill just around the corner from our street. The road is paved, but with just, maybe, a 1/4 inch on the ground, just enough that most of the road was white, but we lost all juice, got stuck not moving, and somehow managed to get off to the side of the road and under a pine tree by going backwards. It was dark, and we hoofed it home. Luckily, it was just a dusting, and with dry roads we drove home fine the next afternoon (it's something lying awake at night, waiting to hear the plow hammer by and wonder if your car was towed or hit).

    So, I agree, Prius is awful in even light snow in my experience. Now, did I play and practice with it? Not much. And those were probably the stock tires (though I can't recall). We have good Michelyn all seasons on there now just to help with rain, etc. We both work below snowline, so full snow tires on the Prius are not an option (our other cars are a Subaru Outback with triple treds and my Tacoma with 31 BFG's...both work great in the snow, though the Goodyears begin to lose their snow mojo a bit around 40K...with two bags of solid concrete in the pickup bed I am fine).

    Up here, as those of you in snow country know, trying to get to work in the pre dawn dark, or get home, good tires in good condition and all the right AWD or FWD are not a luxury of living, they're part of staying alive. Would we have bought the Prius knowing this? Probably. (The salesguy swore the traction control would make our Prius as good in the snow as an AWD).

    And no, I have no interest at all in UAW or any of that; I teach for a living.

    My Prius is sitting in my driveway now, packed snow and ice are on the road, and we're going on a long car trip (1000M) in two days; a storm is coming in tonight; do I dare to try and drive it out before? Not likely, but if I do, I'll let all know how the Michelyns worked. Worst case, AAA can tow me down to dry pavement if nobody smacks me while I'm sitting there.

    My sincere thanks for the many helpful comments on this board. I haven't heard of the software retrofit, but if it didn't cost a fortune we'd do it.
  • wamcowamco Posts: 3
    I own and operate a small limousine company 30 minutes north of Toronto and one of my vehicles is an 05 Prius. I am currently driving airport clients from the Aurora/Newmarket area 3 or 4 times a day, sometimes in severe winter weather and in the early mornings even before the plows have been out! I have recently been out in 15-20 cms. of snow and have had NO PROBLEMS! (touch wood). I installed 4 snow tires with steel rims. This is the first winter I have had it and have found it exceptionally good on the snow. The Toronto area has been hit with a couple of big snow storms this week and the Prius managed very well! I often passed other vehicles stuck on hills or in a ditch. The Prius's traction control does cut the power during slow speed wheel spins but it has never stopped or quit! The traction control always seems to do it's job well. It would be nice to be able to switch off the traction control as you can on some conventional vehicles but I'm OK with the way it works for me. So please spread the word that there is a "Green Limousine" company in the York Region area of Toronto that is eco-friendly and"can get you there safely no mater the weather" - for more info go to:
  • What brand and model snow tires are you using in Toronto?
    I have Blizzak WS-50's on my 2004. They were OK the first winter but are not good now.
    I did use them for 4 winters (off in the spring) but want to replace them with something better.
  • pdxorpdxor Posts: 1
    I think I can understand both points of view. I just experienced my first real snow fall with the Prius. Portland just received 10 inches of snowfall overnight. Unfortunately, the city does not aggressively plow/salt the roads here. The local DOT posted a chains required warning for the entire city. As I do have to report to work tomorrow, I decided to test the conditions in the neighborhood. After shoveling out my driveway, the Prius(2007 touring) hit the streets. I was very impressed. The VSC system is very aggressive. I found that it under a great majority of conditions, it kept the car moving with exceptional stability. All of my previous cars(front wheel drive) tended to pull to one side. The VSC system(yellow light blinking constantly) kept it very steady. I did run into the power cut off phenomenon several times. Essentially, if the car has no traction it will not spin the wheels. This happened when I ran the car in 6-8 inches of unplowed snow. It was somewhat disconcerting, but I do believe that any other(similarly sized, fwd) car would have just been stuck spinning the wheels. Both times this happened, I was able to quickly remedy the problem by gently reversing and approaching from a slightly different angle. It actually is quite adept and doing the most with the least traction available. ( As some of you have pointed out, the Prius probably has less weight over the front wheels than most cars.)
    The Prius does not give you the traction of four wheel drive and you should probably put chains on in severe conditions. If I had the option of driving a 4x4 Duramax in really bad weather, I would. (Sadly I don't) However, I am very impressed with the VSC system. Having experienced midwest and east coast winters all my life, I think this system makes you look good. For example, I am used to building up some speed to make turns with heavy snow buildup. In my older cars, this maneuver would give me some serious "fishtailing". This is essentially eliminated with the Prius. This is without a doubt, the best car I have ever owned for snow driving. (Previous contenders SAAB 900(92-98), VW GTI(99-07))
  • My wife and I both have identical 2008 Priuses/Prii. The problem we're both running in to is that on slightly slippery roads, the car just gives up. You could put the pedal on the floor and you get almost zero power. There's no wheel spin and the engine isn't rev'ing either. It's really annoying but beyond that, I think that it actually is a safety issue. (NOTE: i'm not a UAW worker trying to diss the Prius. And BTW, that's one of the more paranoid assertions I've heard recently.)

    But even in the middle of summer in dry weather, the traction control freaks out. I'll be driving through downtown Boston traffic and get the slip light just by driving over a manhole.

    Is there anything that the dealer can do to ratchet down the traction control?
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