Prius Traction Control Complaints on the Rise

Its probably because many of the drivers have driven other cars with these features and liked how they worked better. Its a different demographic.

IMHO the traction control is very aggressive. My previous car had less aggressive traction control and an off button. An off button is not incompatible with the prius, electronic nanies could still kick in if conditions would cause damage to the drive train. In other words stop being hyper aggressive at taking control from the driver.

That said, I knew about the tc when I bought the car, and bought tires with more traction. I haven't had a problem with my current tires.

Most complaints come from knowledgeable drivers, not some conspiracy of American auto companies.

 

"...not incompatible..."

Given that one of the common uses of TC "off" is, would be, to enable the driver to rock the car back and forth using "wheelspin" to get unstuck... I wonder.

Moving the shifter quickly between forward motion and reverse and forward, etc, might present a problem given the method the Prius uses to move in reverse.

Does the Prius ICE always shut down to move in reverse...?

 

Rocking the Prius is not a problem. Moving the shifter quickly between R and D while applying a little gas does indeed rock the car. I did that myself several times to get unstuck. Prius does allow you to switch between D and R without pressing the brake and even while applying a little gas if the car driver slower than some 4 or 5 mph. It is meant just for this purpose (to allow rocking the car when stuck in snow). Try it yourself, you'll see.

Also, there is a way to produce some considerable wheelspin for a short time in order to try to get unstuck, even with the TC on. Do the following:

1) Step on the brake with your left foot
2) Shift to D or R, whatever needed
3) With the left foot firmly pressing the brake, floor the gas and let the engine rev up
4) Release the brake

The car would hop forward and the wheels would spin like crazy for a short time until the TC kicks in. This is usually sufficient to get unstuck. I invented this method when I was stuck in the snow once and tried to get out by myself. It worked, and I used it several times since then.

In my experience, if you cannot unstuck a Prius using these tricks (been there), you probably wouldn't be able to unstuck any other two-wheel drive car (with or without TC) as well.

I generally agree with the opinion that Prius is not particularly good in slippery conditions and that the TC can be annoying, but it is not totally unusable as well. You can drive around in snow just fine, if you put good snow tires on, drive carefully and learn the tricks above to help you try to get out when you are stuck.

 

I think software limited wheelspin is the key. It makes the software more complicated, but IMHO it can be done while not damaging the drive train.

The ice does not need to shut down when in reverse. The ice does not move the car in reverse though, mg2 does that, and mg1 spins to counter the ice rotation. In that configuration the ice is only on to generate electrity or heat.

 

But absent the driver's "view" wouldn't it be risky for the TC ECU to allow ANY level of wheelspin/slip...? Only the driver can "know", really, when a little wheelspin/slip is wise. That's probably why TC "off" functionality is the chosen solution, let's the driver decide what level of wheelspin/slip, throttle feathering, might be appropriate, and at the same time relieves the manufacturer of any potential liability should an accident result.

"You did WHAT, you disabled a major SAFETY feature...??!!"

Say, starting up on a really slippery surface, might the diff'l allow one front wheel to be "driven" opposite the other...?

 

Yep. The Tesla Roadster has very good traction control from what I've read. It's TC limits wheelspin to a very small level in a way that is in-obtrusive while letting you maintain control of the vehicle.

There is really no situation where anything more than about 10-20% wheelspin that is beneficial. However, in just about all road conditions allowing a small amout of wheelspin (of course taking into account steering angle, vehicle speed and yaw rate) will improve acceleration without risk of losing control of the vehicle.

You could only do this by applying the brake to one of the drive wheels (otherwise without a limited slip diff it's a toin coss as to what wheel will spin). But there's really no benefit to aggressively spinning the wheels.

 

Isn't the Tesla RWD...?

Wheelspin/slip vs directional control not an issue.

 

Sure it is. Haven't you ever done donuts in a RWD car before? It's much less of an issue in a FWD car as I can assure you it's much more difficult to get yourself into trouble by spinning the front tires vs spinning the rear tires.

 

You have a 2004. Jayman also had a problem with his 2004 until he got studded tires (illegal in most of the U.S.). I think they reduced the TC sensitivity after that. My 2006 has always been very good in the snow (not good like my old Subaru wagon, but good like a well-behaved FWD sedan). I use all-seasons, which is fine for the Chicago area. Last winter was a little dicey with 36K miles on my OEM Integrities, but I replaced them this last fall and have had no complaints this winter.

 

I was commenting on a safe background TC to prevent damage to the cars drive components. Driving is inherently dangerous. Most cars do not have traction control, and if a driver wants to disable it and rely on their own abilities I think they should be able to. Toyota really has no idea on my driving situation and have set the TC to be very aggressive IMHO. I knew it when I bought the car and bought better tires so that the electronic nanny would interfere less with my driving. If you don't understand tc and it doesn't bother you, there is no reason to turn it off.

Exactly. BMW and Tesla don't have aggressive tc, but its there. I wouldn't feel the desire to turn them off. My previous Lexus had aggressive traction control, and I turned it off when I wanted to. I liked the fact that it was on in heavy rains and other situations.

 

In northern Minnesota we'd do cookies, but I guess it's just a regional thing.
With FWD you have to put it in reverse and crank the wheels all the over to do about the same thing (it does work in the Prius, even with TC). Fishtailing after a curve in RWD was lots of fun too, as long as you were prepared for it. There's a reason RWD isn't used so much anymore.

 

"..haven't you ever.."

Sure, but only INTENTIONALLY.

"...much more difficult..."

Then I suppose you consider ABS as useless...??

ABS allows you to stear while braking heavily, TC, conversely, allows you to stear while you're (inadvertently?) using too much engine torque for conditions. Some newer FWD models, VW, will actually up-rev the engine if compression braking is resulting in front wheelspin/slip.

A safer tomorrow.

Most modern day TC systems differ in their operation on FWD vs RWD. On a RWD TC will begin braking INSTANTLY with rear wheelspin/slip detection but delays engine dethrottling for a few hundred milliseconds to give the driver long enough to feather the gas. FWD TC systems INSTANTLY brake and dethrottle the engine, too much at risk otherwise.

On my Porsche C4(R/awd) if the back end starts to come around VSC does nothing provided I am quick enough to crank in some counter stearing. On a FWD if the vehicle is not following the desired path VSC will, MUST, INSTANTLY brake the rear wheels and dethottle the engine.

 

"..RWD isn't used..."

The trend, at least in the upscale/luxury market, seems to indicate otherwise. Even Cadillac seems to have now seen the light. But in the meantime look at all the wannabe "AWD" systems, really mostly non-functional F/awd, in the market today as the general public rises on the learning curve regarding the unsafe nature of FWD and F/awd systems on wintertime adverse roadbed conditions.

On the other hand there are three things that seem to go hand in hand as we grow older.

Experience, knowledge and finances.

 

Huh? When did I ever claim that ABS or TC is useless? My only statement was that allowing some wheel spin in a FWD vehicle results in much lower loss of directional control than a RWD vehicle when you are saying that because I mentioned that the Tesla was wonderfully unobtrusive TC that it is irrelevant because it is RWD.

The real reason RWD is used in the upscale/luxury market is because with modern/advanced (more expensive) ESC there is no safety drawback to a RWD vehicle, and that RWD drivetrains tend to be more expensive (why you are seeing this in the upscale/luxury market).

 

Again, my 2004 was helpless with "all season" tires on ice or slush/snow.

Once it bogged down in snow it was impossible to rock. Just remained motionless

Almost every other vehicle with TC has a disable button. The 2010 FJ also has a defeat button, my '07 does not - my FJ however has "real" TC. If one wheel is on glare ice the brake is applied to that wheel

The '04-'09 Prius did not do that. Not sure about the '10

 

"...3) With..floor the gas...let the engine rev up..."

"..the car would hop forward and the wheels would spin like crazy.."

That statement seems "counter" to everything we know, have been told, about the Prius having a built in "brake over-ride" system.

Are you sure..?

If so that would go a long way to explaining the Sikes UA incident.

 

Just as ABS is more about directional control than stopping time or distance then TC on a FWD car should be considered DC, Directional Control. Without "traction" there is no directional control.

Or maybe TDC, Traction for Directional Control.

 

No, this is different than what you are thinking. The brake over-ride will effectively either cut power to the wheels so that you can slow down safely (most GenIIs) or will over power acceleration and allow you to slow down but not feel like you have cut power (reportedly the case on GenIIIs). I've tested the brake over-ride system at speeds up to 100mph.

If you are in Park or otherwise standing still for more than a few seconds, ther engine will shut down. By stepping on the brake and then stepping on the gas you will start the engine and it will rev up a bit but it will not allow the car to move nor will it continue to raise in RPM like you would expect in a conventional ICE car. If you vary throttle position the car will not climb and drop in RPM, it will either turn off or on and stay at a relatively constant RPM. I've done this numerous times when applying engine cleaners that require the engine to be running while you pour/spray the chemical in the intake.

 

I revised my post to include...

"..floor the gas.."

".. The car would hop forward and the wheels would spin like crazy.."

I'm probably wrong but to me that statement reads like the engine revs well above idle with the brakes firmly applied.

 

I'm talking about over the decades. Back in the 70's passenger cars were entirely RWD (AFAIK), by the 90's, most were FWD. There's been some resurgence with RWD because of some advantages in acceleration performance (sports cars and the like). Not because of better handling for the layman in slippery conditions. I've driven both in a lot of ice and snow, but before TC and ESC, etc. were common, I can't really comment on modern RWD.

Right. This comes in handy (on admittedly rare occasions) when you stop at a light and your engine is at say 155'F, you need 157'F to enter stage 4, and that's what's needed to hypermile the next stretch (no 35+ mph stretches). So you force the engine to run for awhile to warm up a bit more, then let it turn off and enter S4. I've heard of this being done to charge up the traction battery, but I'm not sure in what case that would help mpg.

If you let go of the brake while doing this it would accelerate immediately, but really you're two-footing the pedals at this point anyway, so I can't imagine doing this unintentionally.