Is it dangerous to drive a Prius in the snow? ConsumerAffairs thinks so, based on reports they've gathered from several states. It seems that the traction control system in some of the gas-electric hybrids shuts down the power to the drive wheels when they start slipping, a complaint that's been around since last year. Back then Toyota admitted the traction control system could impact performance but isn't a safety problem. Spokesman Bill Kwon stated that a "fairly steep grade [eight to 10 degrees] and … snow would cause a loss of traction which will activate the traction control system and therefore reduce or cut power." Reducing power is one thing, but cutting it out altogether? "In my opinion, it's better to have the vehicle stop then to have the wheels spinning and out of control." That would be fine if the vehicle did stop, but on a snow-covered incline slippery enough to activate the traction control, a powerless car isn't going to stop. For our Prius-owning readers living in snow country, have you experienced this, or has your traction control been behaving itself?
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“In my opinion, it’s better to have the vehicle stop then to have the wheels spinning and out of control.”
That assumes that spinning == out of control. Not at all true.
This somewhat jives with something I saw recently. A friend’s Prius was “stuck” in a small amount of snow. He was trying to rock it back and forth to get out. This generally involves a fair amount of spinning, but he never quite made it over the “hump” without power cutting substantially.
I didn’t realize this was unique to the Prius’ traction control. I assumed all cars with traction control would have the same issue.
I heard that the problem was worse in reverse “gear”.
I think that the “nanny” is attempting to keep the electric motor from overrevving and overheating itself (owners?).
Admittedly, I only did one winter in the snow states, but I distinctly remember TWICE sitting in traffic on slopes, with one foot on the brake, and one foot on the gas, to keep my car “in place” by slowly spinning the wheels because if I didn’t do that, it would start sliding backward toward the car behind me. I wonder how a Prius would handle a spot like that?
Frank Williams said:
That would be fine if the vehicle did stop, but on a snow-covered incline slippery enough to activate the traction control, a powerless car isn’t going to stop.
It won’t stop, because you are still stepping on the gas!
Try braking if you want to stop. When there is little traction, the ABS will kick in and release the brake when it’s skidding.
Traction control is the opposite of ABS. When you are still stepping on gas and your tires lost traction, it should stop spinning. In other words, from what you have described, the traction control on the Prius is functioning perfectly.
Generally speaking, it’s a good idea to turn off traction control in thicker snow, where a little bit of wheel spin is a good thing. My owner’s manual (for my Audi A3) actually recommends it, although I find the Audi traction control gets in the way less than some other systems.
Is it not possible to turn off the Prius traction control?
aelfwyne :
Admittedly, I only did one winter in the snow states, but I distinctly remember TWICE sitting in traffic on slopes, with one foot on the brake, and one foot on the gas, to keep my car “in place” by slowly spinning the wheels because if I didn’t do that, it would start sliding backward toward the car behind me. I wonder how a Prius would handle a spot like that?
You can only hope that the ABS can stop the Prius before it backs into the car behind.
I am living in a very cold city. It’s -40 today, right now. Every year, many cars/SUVs went off the highway into roadside ditches. What happened? Most likely one driving wheel lost traction and stated spinning when the other driving wheel still has traction and thus the car is steered by the two wheels. It can happen very fast and it can be avoided by a traction control identical to the one equipped on the Prius.
I will say it one more time. The purpose of a traction control system is not to stop the spinning of the tire that lost grip. It’s there to stop the spinning of the tire that still has grip, and thus avoiding a steering effect.
No wsn, what I think Frank is pointing out is that gravity will keep the car moving. Cutting power may not be desirable as you may want it to influence the direction you are sliding. All nanny devices should have well placed buttons that are large enough to strike quickly when you want them OFF.
Traction control can indeed make it harder to pull out of snow. Carry some of those grip plates. In an emergency try your floor mats or limbs from an evergreen tree. Both of these methods have put me back on the road.
wsn:
In other words, from what you have described, the traction control on the Prius is functioning perfectly.
The problem isn’t that it reduces power to the front wheels, it cuts it completely. As in shuts the engine and drive motor off, like someone turned off the ignition.
I don’t think anyone would recommend you turn off your car when the wheels start slipping. And in the situations described in the referenced article, stepping on the brakes wouldn’t do any good as the car slides backwards (or sideways) down a hill
We have a long, steep driveway along a treacherous ravine with a particularly steep stretch of eleven degrees. Recently, after a 2 inch snow, my wife was unable to climb the steepest part in her Prius and left it there for me to back it down the hill. She did not mention any power loss. The creeply thing about backing it down was the brakes- you could not feather them between “not enough brake” and locked brakes. And locking them seemed to take a lot of pedal pressure. You have to be looking over the edge of that ravine to fully appreciate this effect.
As far a climbing a slippery hill in a Prius, the battery weight distribution may amplify any traction control issues. At best, on level ground, the batteries’ center of gravity is probably over the rear axle. If so, they do not help with the front wheel drive traction yet we need extra traction to drag them up the hill. Adding insult to injury, as the slope increases, the COG slips behind the rear axle and reduces front drive traction. And at the worst, the batteries’ COG is behind the rear axle on level ground, leaving the front drive light, and traction declines even further as the slope increases. And we still have to drag those batteries up.
John
It’s not just the Prius. Toyota has this idea that they know better than you do. My new 4Runner has the stupid corporate ATRAC and VSC traction control systems. I can’t spin the tires at all (how to you pull someone out of a snow bank). It just cuts power and I sit there. The other day I was going up my driveway and forgot to put it in 4wd. As I entered the rear wheels started spinning, and it cut throttle until I just sat there motionless in the middle of the driveway with the gas floored (Good thing I wasn’t trying to merge). My old 4Runner can make it up the drive way with no trouble, just spin the rears a little and all is well.
I’m happy that I have the nanny, it saved me twice (navigating the new 5000lb behemoth around corners is much different than the old 3600lb 4Runner), but I’m very angry at Toyota for not giving me the option to turn the nanny off for the times that I know I’m smarter than the car. (I also hate that I couldn’t get a real stick to put it in 4wd).
I did find one way to turn it off, but it’s a hack and I don’t know if I want to do that to a new car. And more importantly, I don’t know what the insurance company would say if I had the nanny off.
I hope that Toyota comes out with a factory after market switch to control the nannies. I know they have the ability, they just won’t give it to me.
There’s not many cars that Toyota/Lexus will allow you to turn off the traction control in. Just this year, the Lexus IS gained an easily accessible off-button, instead of the having to disable it through about 14 different actions.
My Chrysler does the same thing with it’s Electronic Stability Program but with a simple press of the button on the dash it can be switched off from “full nanny” mode to “a little wheelspin please”. Believe me that any time the snow is more than a few inches you NEED to be able to disable “HAL” to keep moving forward. Hills are bad but even on a level surface traction control can easily get in the way of correct driving. A LITTLE wheelspin in the snow goes a long way. I can’t see why toyota couldn’t put in a disable mode. oh wait I forgot that the average appliance buyer wouldn’t want that sort of “control”.
Maybe toasters are not meant to be driven after all.
miked
why the 4runner?
If you wanted a stick, the FJ Crusier or the Nissan Xttera have it.
HEATHROI: I’ve had experiences with an ’89 4Runner and a ’95 Nissan Hardbody pickup, the Toyota felt screwed together better to me, so I didn’t even consider the Xterra. I guess I’m too biased towards Toyota (although they don’t get a free pass, if this 4runner isn’t as good as my ’89, I’ll go else where next time).
The new 4runner was bought mainly so my wife could have a reliable 4wd, since we moved to the mountains and _NEED_ 4wd. I have my ’89 4runner and ’76 CJ-5 (200 HJIYC points) as my personal 4wd daily drivers. I really wanted the FJ but she couldn’t see out of it good enough to feel comfortable driving it. That’s really what makes me mad about the new 4Runner, the FJ is the exact same thing underneath and has both an ATRAC disable button and real stick for 4wd.
My 04 Prius has experienced power loss in snow/ice. I was going to mention it to the dealer when I eventually have to take it in for service. However I was able to get going and luckily was never stuck. But it is annoying to feel that the engine is not responding. Glad to see this point brought up. Sounds like it is something one has to learn to live with.
Still, besides the display that won’t work for the first 5 minutes, it is the only annoying thing I have to put up with. Wish all my cars would have been this good. Toyota is number one.
I don’t get this, I though traction control worked better in the snow. My Ford 500 has traction control, and it handles great in the snow and ice. I have pulled up to intersections where other cars where maddly spinning their wheels, and my car would just creep right through the intersection. The ford system allows the wheels to slip just enough to get the car moving, and does not completly cut the power.
C. Alan – The problem isn’t in cases like you see, it’s in situations where you need the wheel spin to keep going. In my case with the 4runner, I can easily get bogged in deep snow (>1 foot) or deep mud where the standard operating procedure is to just floor it and make your way through. Also, if the programming is to aggressive it cuts too much power and you creep along not spinning the tires, even if spinning the tires could get you through the intersection more quickly. Generally, I’m not against nannys as they help you when you make a mistake. I just wish they could be turned off for those few times where you can do better without it.
I’d guess that the Prius’ OEM tires are useless in snow and contribute to the problem. I know Toyota uses very motherly traction control though. I drove a Highlander in the snow and it was terrible; the traction control button turned the light off and on, but didn’t actually have any effect on the overbearing system. I wouldn’t buy any vehicle with traction control that can’t be turned off.
wsn :
January 29th, 2008 at 1:29 pm
I am living in a very cold city. It’s -40 today, right now. Every year, many cars/SUVs went off the highway into roadside ditches. What happened? Most likely one driving wheel lost traction and stated spinning when the other driving wheel still has traction and thus the car is steered by the two wheels. It can happen very fast and it can be avoided by a traction control identical to the one equipped on the Prius.
It’s too cold here to use salt (thank god) so I drive on a layer of snow and ice 5 months of the year and have since I was 16, and I can assure you that what actually happened was that people drove beyond the capabilities of their vehicle, their tires, and their driving skills. The situation you described is not going to cause any problems to a competent driver. The vast majority of drivers have not had traction control during the last 50 years.
I have an ’07 Prius that I put Blizzak REVO 1 snows on for the winter. Most of the time it is fine, but (for example) if you accelerate from a stop and there is some snow/ice on the road, the traction nanny will cut power. I have had it stop the car in those situations. The trick at that point seems to be to “flutter” the gas pedal to get through that slippery area.
I wish I could switch the nanny off for those conditions. It can be very scary when other cars think you are accelerating and the Prius is slowing down. I have noticed that the REVOs make the problem better, as they get better traction/adhesion on the road, even when it is pretty snotty out.
The Prius was one car prominent in my mind when I talked about this problem several weeks ago
https://www.thetruthaboutcars.com/editorials/the-truth-about-automotive-electronics-pt-2-the-bad/
Where’s glenn126 when you need him? He’s been away for quite some time.
Because he lives in northwest Michigan and is now on his second Prius, he ought to be able to give us some first-hand experience in dealing with lake-effect snowstorms blowing in from Lake Michigan.
I climb some BIG hills in snowbound CT in my mom’s Prius and I’ve never had an issue. More significantly, she has no knowledge about any advanced control of cars and she’s never had an issue.
I guess that making a left turn against oncoming traffic could get a bit dicey if there’s snow piled up on the centerline…