I HATE my prius

<div class='quotetop'>QUOTE(MSantos @ Jan 22 2007, 01:07 AM) [snapback]378882[/snapback]</div>

While you are absolutely correct about some people here, this also goes both ways.

Some people are so consumed by the issue that they may have that they are unwilling to accept constructive criticism of how their actions contribute to their issue or things that they can do to help the situation. They whine about the car and refuse to try anything people suggest to remedy the problem.

Now, there have been a few of the posts that you talk about in this thread, but there have been a lot of good responses here that the original poster and other people with the same issue have refused to acknowledge because, quite simply, they want to bitch. They don't want a solution. I see it on these boards all the time.

Let me tell you folks, I am an experienced snow driver, I have driven many different cars in the snow. RWD, FWD, AWD, 4WD. I absolutely can drive our Prius safely in the snow. In fact, I think its better in the snow than my FWD Lexus with VSC and TRAC. Now, my fiance does not like to drive the Prius in the snow but she doesn't have as much experience driving in the snow as I do. (donee wrote a great post about winter driving by the way).

The point is that every car behaves differently in the snow and it takes time to learn what it can and can't do and to adjust. The TRAC in the Prius is overzealous due to the hybrid system. Thats a characteristic thats not going to change, its a tradeoff. In fact, I prefer my snow cars without traction or yaw control because it muddies the feedback I get about the condition of the roadbed. It cannot be disabled on the Prius, but you can work around it.

 

I didn't see this kind of problem regarding the Prius until mine was about 3 weeks from delivered. It gave me grave concerns whether the car would be enough for my life.

I got the car on 2/15/06, so I'm still just under 1 year, have just over 37,000 miles on the original OEM tires, I"m in Chicagoland.

Our driveway is about 130 feet long, concrete, gotta turn at the top to go in the garage.

Given all of this, I've been taking my opportunities to strand myself when it doesn't matter a lot (on a saturday for example). A time or two I've had glare ice, other times, 2 or 3 inches of snow.

When I stop, pointed up hill, then hit the gas to go... Mine paws... if I can put a word to it... kinda one side, then the other side, then the other side, etc... I slowly move forward.

Today we had a couple fresh inches and the roads were plowed except the left turn lane at the intersection I had to turn and I had to stop to wait for the light. When it was time to go, same deal.. pawing side to side, I wouldn't have minded if it took off a little faster, but I really did ok on the deal.

Give me a whopper of a snowstorm where the underside of the car would drag on the ridge of snow between the wheels and I think we're pretty much peckered. I sold a F250 4x4 for the prius. I never had to consider snow depth with that thing. So far, the Prius has saved me $4100 over what I'd have paid to drive that pickup over 11 months, so there's my tradeoff.

Two things... No prius ever built is going to be that great on snow/ice... And, mine is a 2006 and I think it behaves differently than your 2004. Maybe getting software update would make the traction control smarter for you.

 

Unfortunately this is just something thats a tradeoff for the efficiency of the hybrid system. The wheels cannot spin freely in snow, the result would be a burned out drivetrain.

Is it annoying? Yes. Is the car any harder to get started from a stop than a RWD car? No, in fact its still easier. So if you're going to blame Toyota, blame everyone who sells RWD cars. You'd have been just as stuck.

I've driven the Prius in the snow many times, ours is an 04 with no firmware upgrade (didn't even know they had one). Better tires help, but if you're in an area where you get significant snow, snow tires are a must as they are on any car. The stock tires are extremely poor tires when it comes to...just about everything but especially snow traction. Anything will be a huge improvement.

 

Hi All,

I have not had the experience of driving in very deep snow with my Prius yet. I had a 2000 Saturn SL2, and it was marvelous in 6 inches of snow. The traction control really worked well. Based on all the comments here, though, I think the issue is one of perception, not performance.

How does the Prius know not to let the tires slip? It doesn't, it can't, that would be non-causal as engineers say. There has to BE slip in order for the system to power down. We all know how quick the Prius computers are, it detects slip if you hit a man-hole cover accellerating in wet weather. That is literally in the 1/10 th of a second detection and 2/10 ths of a second to act. The only problem is the hang-time of the power down. It needs to be less for summer driving. Hit a slick surface, that is 1/20 th of a second to travel over, and the computer shuts the car down for about 2 seconds. Not good.


Winter weather driving is different however. Speeds are slower, and the length of the slick spots are longer. The cause of the Prius not slipping the tires has to be a sensed slip. But as the computer and sensors in the Prius are so fast, it seems to human senses that the car is not letting the car move, when in reality, its not letting the car slip anymore.

This hypothesis does make sense of all the disparate comments in this thread.

For those of you without allot of winter car experience, in a standard car, if you give the car too much gas, the tire just spins. Yahoo (yea you Texas guys know who you are!) drivers will attempt to gun it even more , but the car will just sit there all the same. If the surface is warm snow, the tire will dig down to pavement, but this is an extreme rarity. Usually, one just blows away snow until the tire reaches hard-packed snow which has turned to ice. Spinning the wheels just polishes the ice, making it more slippery. Even if one were to dig down to pavement, that just moves the car back onto snow, and the process repeats.

People help each other in northern areas in these situations. This is why I think lazyleo is not a northern driver. His attitude toward others that might see his plight is completely opposite of northern winterbound people. The common method is to get two or three people at the back of the car, and try to push the car up out of the hole the tire has dug, or the snow has formed around the car. The driver must be careful to only give gas in synchrony with the push, and then only enough that the wheels do not brake traction. The Prius does this careful throttle minding automatically.

Oh, and yea, once your moving, do not stop! The common garage parking up an unplowed driveway is to pass the house the first time to trigger the garage opener, then proceed around the block. At the second approach, aim for the near side curb at the drive way and crab-slide diagonally across the drive way, up on to the dry garage concrete, hit the brakes and stop before going through he back wall. Sounds bizarre, but I have done this on many occaisions. Its not that unusual. Getting out is easy just goose it on the dry indoor garage pavement, and cut throttle to the maintain speed level, down the driveway. Make sure there is no traffic up or down the street when you do this. These are not Prius-centric things. Just normal winter driving.

There are two friction domains. These are called STATIC and DYNAMIC friction. Static friction can provide more force, but has a limit. Exceed the limit and objects in contact will begin to slide - that is transistion into the dynamic friction domain. Dynamic friction has dramatically less capability to generate force. To move out of a slick situation, one needs to stay in the static friction domain, and accellerate like a rocket does at lift-off. VERY slow at first, then with VERY constant accelleration. If you overload the power capability of the tire/snow surface, you will drop into the dyanamic friction domain, and quickly decellerate.

Traction control when it works well, like on my Saturn, would prevent the car from loosing momentum. The slipping wheel was braked, and torqure mainitained (BUT NOT INCREASED) at the wheel that was not sliding. The car kept moving, and the sliding wheel brake then released. Now the question is does the Prius cut power to both wheels, when only one is slipping, or both ?

Now my Saturn would do the same power cut, just not on man-hole covers. The computers were apparently too slow, or the low end torque too meager. But, there was one intersection, where one Y's onto a passing road, with a slick spot at the stop-sign. If it had just rained, the slick spot would be greasy with a mixture of dust, water and oil. Sure enough, push the throttle hard there, and the engine would cut back. Even though it was just the right hand wheel slipping. Although counter intuitive, the best thing to do was to push just a little harder on the throttle, and steer to see if a tire edge would catch dry pavement. All this while cars are bearing down on the road one is trying to merge with. I see this as similar to what people are talking about, and not a Prius thing at all. Without the traction control, the car would not move at all, and the chance of an accident would be even greater. With the traction control, the car would move at the same speed it started slipping, until it was past the slick spot, and away the car would go. Eventually, I was so ready for this, I would even know how much extra distance to leave to be safe.

In winter driving, the situation is much the same, but you need to leave the extra merging time EACH AND EVERY merge situation. And it takes time to gain the experience of how long the car will take to accellerate, and on what kind of surface. Yea, its dangerous, but go and tell some federal agency that you do not like driving in the snow, its dangerous, and they are going to laugh at you. Drivers on the through roads also know to slow down when they see a car ahead that is ready to merge. Not that your going to stop and let that car in, just so that you can stop if that car screws up and tries to merge when it can't. And cars behind other cars follow at a big distance, and very carefully.

Getting used to the patient deliberate driving style needed for winter weather can be very frustrating for experienced southern drivers. One slick morning on my tollway compute to work, all the winter experienced people were very carefully tending their following distances, and driving just short of slipping speed at 40 mph. There was also this guy with Texas plates. He just could not drive that slow, and did not have the bottom senses to realise there was a VERY sharp transision just above 40 mph where the cars would slide. So, up he comes, weaving along, getting more confident. Then at 50 mph, wham,,540 degree loop-de-loop and up a bridge embankment. slid sideways back down the embankment and was stuck in ruts in the muddy grass. In the meantime the 1000 or so of us other drivers on the road at the time just kept running along stable, and safe at the fastest speed the road would allow. Not one Illinois driver was anywhere near this guy when he lost it, and not one was involved in his accident.

If both wheels are slipping though, even traction control will not help to move the car. If the Prius Traction Control senses slipping in both wheels, the car is not going to spin the tires uselessly. In a standard car, the winter driver does the same thing, only that the time it takes for the sensation of tire slipping is 100 times slower. Just because something seems non-Causal, does not mean it is.

 

<div class='quotetop'>QUOTE(lazyleo @ Jan 21 2007, 01:00 AM) [snapback]378583[/snapback]</div>

Sorry to say this lazyleo: Some folks around here are no help at all. They live in a crystal little world of their own, and if you introduce them to the rest of the world (which certainly represents a much larger reality than their own) you'll disturb them enough to get the insensitive and ignorant responses you got. Who says you need to be smart to own a Prius?


As some posters have already mentioned, this traction control thing can be annoying especially when you need it the least. I have a 2007 and I have already been immobilized going up my driveway ... and I sport Michelin X-Ice on all four corners. As Tideland mentioned, there may be an update to make things easier.

In my case, because I swore it would never happen to me again, I now pack a lightweight shovel and a bag of road salt in the back.


Cheers;

MSantos

 

<div class='quotetop'>QUOTE(jburns @ Jan 20 2007, 09:17 PM) [snapback]378461[/snapback]</div>

I'll third this. I've had the unsettling "where did the power go?!?" sensation in rainy weather; unless you feather the throttle *immediately* and then feed in the power gradually (all of this happening in a second or less, and repeated as necessary) the car will indeed just creep forward, no matter how far you press down on the throttle.

As I've said before, unless the car also has eyes on its side so it can see if we're about to be broadsided by an oncoming vehicle, I'd prefer that it kept its opinions to itself!

I think, as I get more experienced in the car, I'm becoming more fascile at working around the traction control issue...but it'll always remain a workaround. You're right, in my opinion too this is potentially a safety issue. The combination of lots of torque from a standstill, the lack of some sort of locking differential, the intrusive traction control and the somewhat under-tyred nature of the Prius does seem to make drivability a bit too inconsistent under a few too many circumstances.

Don't get me wrong, this is to me more of a challenge than anything, but I can see how it can really surprise one if one is not quite as analytical about the car as we are here on PC. I'd be curious how this shakes out over time, especially if the '04-05's are even worse than the 06-07's.

 

<div class='quotetop'>QUOTE(MSantos @ Jan 21 2007, 10:07 PM) [snapback]378882[/snapback]</div>

Some people believe that if they haven't experienced a problem, it doesn't exist. Wth is up with that?

 

<div class='quotetop'>QUOTE(lazyleo @ Jan 20 2007, 07:07 PM) [snapback]378384[/snapback]</div>

If you press the gas pedal and shift into drive, the car should spin the tires. <_<

 

<div class='quotetop'>QUOTE(Tideland Prius @ Jan 21 2007, 01:36 PM) [snapback]378719[/snapback]</div>

Got it and understand it. My wife's car late 2005 production and definitely doesn't do that. So that was, in effect, an outright error in trac that was fixed, but which mine never had.

I took my wife's Prius out on yesterday's snow here in No VA and it definitely doesn't do that. Accelerate too hard at startup and the drive train pulses as the trac cuts in and out, but the car definitely moves. I didn't think to stick my head out the window to check for spin.

The car does fine in typical Virginia snow conditions --30 degrees F, less than 1 inch of mixed freezing rain, sleet, and snow frozen to the road. Stops nice and straight with the wheels locked. In all respects, it handled as well as any other small FWD car I've owned, in these conditions. Traction and manuverability were ultimately limited by tire grip, and nothing else, in these conditions. And I definitely understand the other posts about the OEM tires now.

But I can see where the TRAC might prevent me from grinding my way out of a small depth of snow (e.g., 2 inches of icy slush), where a traditional FWD car would be able to do that under the right circumstances. That's definitely going to require extra caution if we ever have any depth of snow here.

The important consideration here is that Lazyleo has a 2004 Prius. So maybe he needs the software upgrade? Has that been determined in this thread? Because the behavior you describe, as to how your car behaved prior to reflash, is clearly an error and clearly does not match how mine behaves. Maybe Lazyleo needs both new tires (or tyres, depending) and a reflash.


I went back to look at the recent "stuck in the mud" thread, but that was a 2007. So this won't solve every traction problem but, for a 2004 with an issue, would seem to be worth considering.

 

I've got a Classic Prius and have *never* had any issues with the car getting stuck on ice, snow, or even deep mud (I have all three here in Canada, out at the barn); granted I have decent tires, but even so, if I chose to be agressive, I've *always* been able to spin them on ice and wet pavement before traction control cut-in, and thereafter the power cut in and out in short bursts (sometimes with more wheel spin) until the car was going steadily again...

I know that spinning the wheels could result in high RPMs in the electric motors and that was the motivation for the electronic control in the first place, but I'm wondering if the issues people are experiencing in the HSD Prii are more related to the fact that its motors are wound for 500V vs. 273V in the Classic.. Certainly the high RPMs could stress the mechanicals, but it can also induce high voltages in the windings: inductive EMFs can easily reach double or more the normal operating voltage- on the Classic, you're only talking maybe 600-700V which is manageable, but on the HSD, you could potentially see spikes well over 1000-1500V, which could easily arc and do some damage- so I'm thinking that this could be the reason for why the traction control on the HSD seems to be so much more sensitive than on the Classic.. Otherwise I can't think of any reason why they would change the traction control behaviour vs. the Classic, and I don't ever recall any accounts of Classic owners getting stuck, only HSD..

I've been considering upgrading to an HSD model this year, and while there are many things I like (larger cargo area, better performance) and things that I'm not crazy about, but could live with (I don't like the styling of the dash and console and all the painted plastics- I much prefer the styling and plastics in the Classic), the one issue that is still giving me pause is this traction control issue..

 

I've got a Classic Prius and have *never* had any issues with the car getting stuck on ice, snow, or even deep mud (I have all three here in Canada, out at the barn); granted I have decent tires, but even so, if I chose to be agressive, I've *always* been able to spin them on ice and wet pavement before traction control cut-in, and thereafter the power cut in and out in short bursts (sometimes with more wheel spin) until the car was going steadily again...

I know that spinning the wheels could result in high RPMs in the electric motors and that was the motivation for the electronic control in the first place, but I'm wondering if the issues people are experiencing in the HSD Prii are more related to the fact that its motors are wound for 500V vs. 273V in the Classic.. Certainly the high RPMs could stress the mechanicals, but it can also induce high voltages in the windings: inductive EMFs can easily reach double or more the normal operating voltage- on the Classic, you're only talking maybe 600-700V which is manageable, but on the HSD, you could potentially see spikes well over 1000-1500V, which could easily arc and do some damage- so I'm thinking that this could be the reason for why the traction control on the HSD seems to be so much more sensitive than on the Classic.. Otherwise I can't think of any reason why they would change the traction control behaviour vs. the Classic, and I don't ever recall any accounts of Classic owners getting stuck, only HSD..

I've been considering upgrading to an HSD model this year, and while there are many things I like (larger cargo area, better performance) and things that I'm not crazy about, but could live with (I don't like the styling of the dash and console and all the painted plastics- I much prefer the styling and plastics in the Classic), the one issue that is still giving me pause is this traction control issue..

 

WOW!! I was gone for less than 2 days and I have a ton of PM's already in my folder inquiring about my "mod" to disable the TC!! I really did not want to post this openly but since there are so many people that wanted to know what I did, this is the most effecient way rather than responding to each indvidual PM.

Disclaimer: Doing this to your car may result in the car expoding in a million pieces causing massive casualties in a 20 block radius. In other words, if you chose to do this mod and something goes wrong, do not blame or sue me, the owners, moderators or users of PC... okay?? Seriously speaking though, disabling the system should ONLY be done in the case of an emergency as it is usually MUCH more advatageous to have the system active such as when driving on slipery or wet roads and such. I ONLY disable the system in the event where I am stuck and NEED to turn the front wheels when the rear wheels are not moving. AT ALL OTHER TIMES THE SYSTEM SHOULD BE KEPT ON AND ACTIVE!!! DOING THIS MOD WILL PROBABLY VOID YOUR WARRANTY AS WELL SO THIS INFORMATION IS PURELY MEANT TO BE INFORMATIVE IN NATURE!!

Now that all of the legal jargon is out of the way here is basically what I did.

The first time I experienced one of the "limitations" of the Prius was when I put it on the chassis dyno take some power measurements. For those of you that remember this post, I had a hard time just to be able to get the front wheels to turn the drums of the dyno because the traction/vsc would kick in and bring the fun to an alarming halt. I tried pulling fuses, relays even some kind of emission procedure that involved a certain sequence of pressing buttons followed by florring the gas pedal but nothing would allow me to spin the front tires; Then it occurred to me.. The computer is looking at ALL 4 wheels and when it sees tha the fronts are are turning but the rear wheels are not, the Prius instantly throws an error code and the result is that the car does not go anywhere.

I also experienced this when I was driving on a dirt road to my cabin. Once the car was stuck in the sand no amount of throttle would do anything and I was forced to call in the "hook" to get me out of there.

At this point I was DETERMINED to bypass this nightmare so here is what I did:

On the rear of each wheel there is a speed sensor. If you simply unplug this sensor on the left and right rear wheels you have effectiviely disabled the traction/VSC control allowing you to floor the gas pedal in any condition. This WILL throw a check engine light on the dash board but everything works as normal with the exeption of the VSC/Traction control. Most times it IS advantageous to have this working properly so what I did was to splice in an DPST switch and wired each speed sensor to my switch in the car. When the switch is in the "ON" position the connection is made and everything works as it should. When it is in the "OFF" postion, the connection is cut and effectively the traction control and VSC is OFF. Please note than when you turn it back "ON" it will take aproximately 20 miles or so for the car to realize that the system is working again and for the check engine light to go out on the dash.

That's all there is to it. By disconnecting or interupting the signal going to the speed sensors you can disable this "feature" and honestly IMO Toyota should have included this as standard. There are situations whether it be snow or sand or other situations when it is necessary to have the slip to obtain traction.

Again, if you chose to do this you are doing so AT YOUR OWN RISK!!

 

<div class='quotetop'>QUOTE(BT Tech @ Jan 22 2007, 11:14 PM) [snapback]379327[/snapback]</div>

Thank you. That's a really handy thing to know. Hope I never need it, but very glad to know it.

 

Has anyone read this? See page 17.

http://www.toyota.co.jp/en/tech/environmen...lReports_12.pdf

 

<div class='quotetop'>QUOTE(SW03ES @ Jan 21 2007, 08:35 PM) [snapback]378830[/snapback]</div>

This is exactly why nobody has put hybrid pickup trucks on the market. About three years ago, it was reported Toyota was very concerned about motor burnouts on stuck pickups.

....back to the topic

 

<div class='quotetop'>QUOTE(Delta Flyer @ Jan 23 2007, 09:12 AM) [snapback]379452[/snapback]</div>

Is lack of ability to spin the wheels really an inherent and uncorrectable problem with the HSD and hybrids in general? I'm not trying to be argumentative, I'm looking for an answer that I understand.

What I've heard so far is that totally uncontrolled wheel spin could give you motor burnout. What I haven't heard is why Toyota couldn't program the HSD to allow (say) 5 mph (dry-pavement equivalent speed) in wheelspin before holding power at the level that maintains no more than that wheelspin. Just so I could dig myself out of a few inches of snow. I mean, with all the tricks they can make the car do with VSC, I have to believe they could do this.

The (excellent!) document linked by display name above, page 17, suggests to me that Toyota indeed *chose* to cut power to zero in when wheel slip was detected. The situation they programmed the car for was (e.g.) smooth wet pavement wheel slip, for which you definitely would *not* want to allow the wheel to continue to slip, if your goal was to reacquire traction asap.. Programming it the way I suggest above (limit slip to some low MPH) would not restore traction - you'd just continue to slip.

So, my take on this is that Toyota chose what they believed would be the optimal parameter (cut power to zero momentarily if there is wheelslip) with the aim of restoring traction *on a smooth-but-slippery surface*.

What they did not anticpate is that wheelslip can occur in at least two other situations where it might be HIGHLY DESIRABLE to have some limited wheel slip, because you are trying to move loose crap out from under your wheels, mainly a) a thin layer of loose gravel/sand on the road, and b) a thin layer of loose snow/ice on the road.

In other words, the heart-stopping power loss when you try to take off with gravel under the front wheels, and the pain-in-the-butt power loss when trying to dig through loose snow, appear to me both to be consequences of Toyota's *decision* to program the HSD traction with smooth slippery pavement in mind only, and without considering situations where traction loss is due to loss objects under the wheels that you'd like to be able to get rid of.

The fact that BT Tech can do this occasionally without grenading the HSD also suggests that Toyota had some design leeway that it just chose not to use.

I'd suggest that the best of all worlds would be two-mode TRAC -- zero slip for those who prefer that, whose typical wheelslip is in fact the smooth-wet-pavement scenario. And "minimal" TRAC, where the car would just do enough to prevent you from burning out the HSD, but would otherwise let you spin the wheels a bit.

Because right now the options are stock TRAC or disabled TRAC. That's not optimal. The fact that a whole bunch of people immediately asked for a way to disable TRAC ought to send Toyota a message on this.

Anybody who actually understands how the HSD works, please correct this if I have it wrong.

But my summary on this is that a) Toyota in good faith chose this zero-allowable-slip TRAC setup, thinking of smooth-wet-pavement scenario, b) but their thinking did not anticipate the loose-objects-under-the-wheels scenario, c) a bunch of loyal Toyota customers are asking how to turn it off, fully knowing that d) turning TRAC off entirely can be bad for the HSD, so e) Toyota ought to offer a limited-slip setting on TRAC, to protect the HSD while allowing you to get the gravel/snow out from under the drive wheels.

 

If the wheels of any hybrid or EV become stuck and the electric motor is under load but not turning, burnout is a grave risk. :blink:

Forced to choose between the two, I'll gladly take the software that intercepts stuck or spinning wheels.