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Discussion Starter #1
I was just reading an atricle in the new Car And Driver about a Prius at Bonneville. This 130 mph prius had major modifications and one worry was that the traction-control would kick in and kill any acceleration. The article says that "by stomping the brake and the gas in a precise sequence, he could tell the computer to disable the traction-control system". It is not known wether the trick worked. The car had problems getting out of neutral.
Anyways, in short, the traction-control on the Prius is horrible. The system TOTALLY cuts power to the wheels whenever ANY wheel-spin is detected. Ive read on this site and others that the traction control is excellent and wheel-spin is not ever necessary and just being "macho". Anyone who thinks this is very confused. There are many times when wheelspin is not only necessary but mandatory. Snow, gravel, mud, sand and wet grass are some of the driving conditions where wheel-spin may be the only way for forward or rearward progress. For those of you that say "push" or "carry a shovel", do you suggest that to my 8 month pregnant wife when the Prius stops dead on a minor grassy hill leading to our back door. I mean the car stopped dead. A little wheel-spin would have solved the problem, besides, the grass will grow back.
Enough of my rant.
I need to find a way to disable this cursed annoyance. Both the misses and I are very capable drivers and in most situations are probably smarter than the car. Please help us control this control because winter is coming and our rural roads can go unplowed for days.
Thanks
 

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Mine has a TC switch that turns it on and off. like the Holden senator (only other car I have been in with Traction Control)
 

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ElvisPrius said:
The system TOTALLY cuts power to the wheels whenever ANY wheel-spin is detected. Ive read on this site and others that the traction control is excellent and wheel-spin is not ever necessary and just being "macho". Anyone who thinks this is very confused.
If the wheel is spinning, you have no additional traction from that wheel. Maximum forward force will be achieved just short of the breakaway point.

Worse yet a conventional differencial, which I assume a prius has, provides maximum torque to the faster spinning wheel. This means that the wheel that is on the slick spot gets more of the engines power than the one on the dry spot, and the more power applied, the greater the loss of power to the wheel with traction.

What traction control does is stop the free spinning wheel so that the non freespining wheel can get some traction.
 

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Discussion Starter #4
Skip, what you fail to realize is that when both wheels are on the same slippery surface the idiotic traction-control cuts in and all forward motion is stopped. Wheel-spin would with out a doubt help. Spinning the tires would let me claw down to where there is traction.
If the Australian Prius has an on-off button, why can't mine?
 

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i think to "claw down" to pavement only works if the surface can be clawed down to. what good is it to clear one small patch of road just to roll onto another slippery patch of road and be in the same situation??

Toyota assumes that slipperage comes from driving too fast for road conditions and I for one thinks Toyota did it right.
 

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Roger said:
Mine has a TC switch that turns it on and off. like the Holden senator (only other car I have been in with Traction Control)
Roger, where is the switch and have you made any effort to see where the wires go? Do you have access to the wiring diagrams for your Aussie Prius?
 

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Discussion Starter #7
Roger, you stated "what good is it to clear one small patch of road just to roll onto another slippery patch of road and be in the same situation??"
You have already answered your question. "Roll" is the key word here. The word suggests movement and therefore inertia. Movement and inertia are exactly what you need to get you moving when you are in a slippery situation.
I think the T-C has its place, but there should be a way to defeat it when it gets confused. I don't need or want electronic traning wheels all of the time.
 

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I experienced what I guess was traction control when starting from a red light. It was very disconcerting. It felt like the car was missing or stalling. This was on a dry road. It must have been a glitch, but I'm not looking forward to snowy conditions.
 

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My 2002 GTI had a switch to turn off traction control and the car manual mentioned that under some circumstances this would be necessary; in circumstances such as mentioned above. My brother in law's 2004 Chrysler 300 also has a switch.
 

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ElvisPrius said:
Please help us control this control because winter is coming and our rural roads can go unplowed for days.
Elvis,
I'm not sure why Toyota decided against an on/off switch for the traction control--more than one person here has claimed a need for such an option. However, even if they had installed one, it seems to me that your particular situation may result in less than optimal performance. After all, with or without traction control, it is likely that the Prius will have trouble handling unplowed rural roads. If I were you (and I'm not trying to be a smart aleck) I would consider a different vehicle altogether--especially if I had a wife and baby out driving on a cold winter's night.

Moo :)
 

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You definitely need to be able to turn it off, such as in the situation described by ElvisPrius. Traction control is good for drag racing tho. :lol:

The constant spinning of wheels and the resulting creeping forward is sometimes the only way to get out of being bogged. traction control doesn't allow this to happen and so makes sure you stay bogged. Hence the switch.

Mine is located to the left of the steering wheel, (so between the steering wheel and the centre of the car) and there is a blank same shape/size area next to it for another switch.
 

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I used to have a Camry and one fine snow covered winter morning, I found that I couldn't drive up the hill from my house. There was NO WAY that I could get my tires to turn at a slow enough speed even in low gear, to keep the traction control from kicking in and stopping the wheels altogether. After wondering for a few minutes how I was going to get to work, I remembered that there was a switch to turn off the traction control. I spun my wheels up the hill and got to work on time. I am in complete agreement with ElvisPrius. There really needs to be a way to disable the traction control in those rare circumstances where it literally prevents you from driving your car. I am not looking forward to driving in the snow or, even more so, on ice. Those of you who think that driving with permanent traction control is no big deal must not have any hills in your neighborhood...
 

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Disclaimer: Heresay and bad memory at play....

I thought someone told me that the reason we can't disable TRAC in the Prius is to prevent overspinning in the planetary gears or something. Seems that it could damage the system.
 

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Evan,

I remember hearing that before too. I'm still gonna be mighty bummed when/if I get stuck this winter... I'm keeping my fingers crossed. The Prius IS slightly less gravitationally challenged than my old Camry I guess :D
 

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Discussion Starter #16
Id like to respond to the suggestions made by the few sheeple that told me to either not drive on my lawn or buy a new set of tires or a new car.

1. We live in the country, people drive on their lawns, always have, always will.

2. The tires are not the issue. We have had many cars drive up around the house with plain old tires, sometimes bald. My wifes 9.3 Saab always made it with 50 series Z-rated skins. As I said before, it's the T-C thats causing the problem.

3. The car is not the issue. The lack of a $10 switch is. When it is cold and snowy out which of my vehicles do you suggest. My Ford F-250 Crew Cab Diesel with 33 inch mud tires or my Ford F-450 Diesel also with mudders and a 15,000 lb winch or my John Deer 4X4 tractor or a Case 350 Bulldozer. My Yamaha YZ250F dirtbike with carbide studded Trelleborg tires would be a little chilly. I know, I'll take the little lady out on my 150HP Yamaha RX-1 snowmobile. I dont think so... she likes the Prius.

Bye the way, thanks Roger and Stevesol. I new someone out in Prius land new something about driving.
 

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efusco said:
Disclaimer: Heresay and bad memory at play....

I thought someone told me that the reason we can't disable TRAC in the Prius is to prevent overspinning in the planetary gears or something. Seems that it could damage the system.
Since the Prius protects itself in other ways (e.g. not letting the battery charge get either too high or too low), "one more way" wouldn't be surprising.
 

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OK, here's some informationn from the repair manual. However, it does state that spinning the front wheels can damage the vehicle (see part I bolded). Do this at your own risk.
This will disable the TRAC and keep the engine running.

5. INSPECTION MODE
HINT:
 The PRIUS’ engine automatically stops if the vehicle is stopped, the engine is warmed up, the battery
is well charged, and A/C compressor operation is not being used. Activate inspection mode when continuous
operation of the engine is required.
 The PRIUS has a motor TRAC function. When the wheel speed of the front wheels exceeds that of
rear wheels, the wheel speed of the front wheels is restrained. It is necessary to activate inspection
mode and deactivate the motor TRAC function when turning only the front wheels using a speedometer
tester.
(a) Vehicle conditions
(1) Before activating inspection mode, turn the air conditioning off, start the engine with the selector
lever in the P position, and check that the engine stops within several seconds after starting (engine
warm up check).
(2) Activate inspection mode and inspect the vehicle. The shift position for each test is as follows:
Test item Shift position Inspection mode
1. Vehicle straight travelling test
(side slip inspection)
D ON or OFF
2. Breaking force test N ON or OFF
3. Speed meter test D ON
4. Exhaust gas test (idling) P ON
5. Headlight test P ON or OFF
(3) Reset inspection mode immediately after completion of inspection.
NOTICE:
Driving the vehicle without resetting inspection mode may damage the transaxle.
(b) Special notes for speedometer test
NOTICE:
Do not use the speedmeter tester to perform rapid starting or quick accleration/deceleration without
first setting the proper load on the vehicle. Failing to set the load may damage the transaxle.

(1) Depress the accelerator pedal slowly and gradually accelerate the vehicle. Make a measurement.
(2) After the measurement, use the brake to gradually decelerate the vehicle.
(c) Special note for using the chassis dynamometer
Always set an appropriate load before starting the test.
(d) Activating of inspection mode (NOT Using the hand–held tester)
Perform the following steps from (1) through (4) in 60 seconds.
(1) Turn the power switch ON (IG).
(2) Fully depress the accelerator pedal twice with the
transmission in the P position.
(3) Fully depress the accelerator pedal twice with the
transmission in the N position.
(4) Fully depress the accelerator pedal twice with the
transmission in the P position.
(5) Check that the HV system warning lamp flashes on
the multi–information display.
(6) Start the engine by pushing the power switch, depressing
the brake pedal.
 

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Discussion Starter #20
Dan I do believe that you are the man! That's the kind of info that makes me happy. I believe this is what they were trying to do in the Car And Driver article.
If the car can survive a dyno run, why would spinning the wheels hurt the car? I wonder if this trick does the same thing as the Austrailian defeat switch. If the men from down under can spin 'em without hurting their cars , why can't we?
Maybe Big Brother Toyota just wants to scare all of us lawsuit-happy Americans into driving the cars with all of the "safety systems" enabled.

John, if the stock All Season tires prove to be inadequate after we disable the T-C, I'll order up a set of Blizzaks.

Thanks
 
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