Thinking about disconnecting traction control

syncmaster · 11-22-2005, 08:01 PM

How many times has this happened to you?
You are waiting to pull out of a shopping center into fast traffic. You see a chance to pull out and floor it. The prius starts to take off and then the traction contorl kicks in because the wheel slipped a little and the the car hesitates a half second before it again tries to accelerate .
I heard from a prius owner that he had a steep gravel driveway and he had trouble going up with the prius because the wheels would spin a little in the gravel and the traction control would keep cutting in.
I am thinking about adding a switch so I can shut off the traction control.
I think if you open the wires going to the sensors in the rear wheels that would disable the traction control but would the also disable the stability control?

Has anyone tried it ?

I would like to hear from others on this subject.

Thanks for you input!

jayman · 11-22-2005, 08:21 PM

Well, that has happened to me too, especially on icy intersections. I don't think trying to disable the Trac is a good idea, you could destroy the power split device.

I do wish Toyota had considered the climates the car would be operated in, and offered a "cancel" button that would desensitise the Trac algorithm. Otherwise you really do need good sticky studless or studded winter tires in winter.

ceric · 11-22-2005, 08:41 PM

I agree with jayman,
what you really need is better tires at four corners. If traction is lost, w/o TC, the tire just spins. That won't help what you would like to achieve. Sticky tires for summer and snow tires for winters are the ways to go.

Tempus · 11-22-2005, 09:14 PM

I agree with the previous opinions.

Disabling Traction Control because your wheels are slipping is compounding the problem, not making it better.

Yes, your approach might also affect Stability Control, and even possibly ABS.

If you do decide to go ahead, be sure to cut the wires to the air-bags and disable your seat belt warnings just to be complete

**Tideland Prius** · 11-22-2005, 10:57 PM

I think it's cheaper to get a set of better tyres than replace the electric motors and/or PSD.

Mojo40 · 11-23-2005, 12:07 AM

The physics behind traction control are that sliding friction is less than static friction. In other words, a spinning tire get you less grip on the road than a non spinning tire.

Now, this next part is not fact, but my interpretation (can anybody verify?) Traction control as implemented in the Prius does two things, 1) applies the brake to a wheel that is spinning, thus driving the torque to the other wheel that has a better grip, and 2) backs off the engine power until the wheels can grip.

Here's the key point. Although the engine backs off on power to maintain tire grip, the Prius is probably giving you better acceleration than if the engine was racing and the tires were spinning. Again, this is theory, and I don't have data to back this up.

I did read an article a few years back about this technology being applied on a two wheel drive Saab. It provided winter driving performance equivalent to an all wheel drive.

As far as cutting wires - you have to be completely nuts to try and reengineer a sophisticated, highly integrated system like this. Just leave it alone. Go get an old VW beetle and reengineer that.

**Tideland Prius** · 11-23-2005, 01:02 AM

Mojo, what you described is traction control on normal cars. I think the Prius does it differently. Something with the electric motors rather than the brakes being applied.

Also, unlike other TCS's, if you keep your foot there, you won't go anywhere. I've tried letting go and pressing again and the whole car seemed to have "stalled". In other TCS, if you kept your foot on the accelerator, all you'd hear is the tyre spin, stop, spin, stop and so on until you regain traction. With the Prius, I got nothing. Zip zero nada. I had to go into reverse to get any power to the wheels.

oly_57mpg · 11-23-2005, 02:03 AM

Has anyone seen the post from Club Lexus about disabling vdis?
http://clublexus.com/forums/showthread.php?t=187987

start the car with the parking prake on ....then foot brake twice....(keep the foot brake down)....then parking brake twice (keep it down )and repeat till skid light is on the dash

syncmaster · 11-24-2005, 07:12 PM

here is a link to someone having problems getting up their driveway because of Trac control.

http://priuschat.com/Slippery-hills-vs-TRAC-t12883.html

I copied this section from the posted link above, USE AT YOU'RE OWN RISK.

to disable traction control on the prius:
1) Turn the car to ignition by pressing START twice without pressing the brake.
2) Floor the gas pedal two times (two full top to bottom pressings)
3) Make sure the Emergency brake is on now and put the car into NEUTRAL
4) Again press the gas pedal two times
5) Push PARK and press the gas pedal two more times
6) Now put your foot on the BRAKE and press START one time while holding the brake down.

The prius will reset traction control to normal the next time you start it.

Alainc · 11-29-2005, 03:14 PM

How can you (step 3), put the car in NEUTRAL since the Hybrid is not READY. You are only in the ignition mode from step 1).

I tried these steps and .... the drive selector isn't doing a thing so .... you can't get to NEUTRAL. In fact if you push the selector to NEUTRAL, the car beeps at you after keeping it there for 2 sec or so.

Alain

Quote:

Originally posted by syncmaster@Nov 24 2005, 07:12 PM
here is a link to someone having problems getting up their driveway because of Trac control.

http://priuschat.com/Slippery-hills-vs-TRAC-t12883.html

I copied this section from the posted link above, USE AT YOU'RE OWN RISK.

to disable traction control on the prius:
1) Turn the car to ignition by pressing START twice without pressing the brake.
2) Floor the gas pedal two times (two full top to bottom pressings)
3) Make sure the Emergency brake is on now and put the car into NEUTRAL
4) Again press the gas pedal two times
5) Push PARK and press the gas pedal two more times
6) Now put your foot on the BRAKE and press START one time while holding the brake down.

The prius will reset traction control to normal the next time you start it.

[snapback]161185[/snapback]

11-23-2005, 01:02 AM	#7
Tideland Prius Moderator of the North Join Date: Oct 2004 Location: Canada Posts: 20,192 My Car: 2010 Prius Model: N/A Package: Technology Package (Canada) Thanks: 274 Thanked 419 Times in 284 Posts Friends: 23	Mojo, what you described is traction control on normal cars. I think the Prius does it differently. Something with the electric motors rather than the brakes being applied. Also, unlike other TCS's, if you keep your foot there, you won't go anywhere. I've tried letting go and pressing again and the whole car seemed to have "stalled". In other TCS, if you kept your foot on the accelerator, all you'd hear is the tyre spin, stop, spin, stop and so on until you regain traction. With the Prius, I got nothing. Zip zero nada. I had to go into reverse to get any power to the wheels. __________________ 2005 Tideland Pearl Premium Package 25/10/04 VVT-i Emblem, Sport Pedals, All-Weather Mats, Cargo Mat, EV Mod, JDM Prius Footwell Lighting, DICE iPod Kit 2008 Deep Black smart fortwo passion coupé - sold (6.1L/100km) 2010 Blue Ribbon Metallic Technology Package 29/08/09 All-Weather Mats, Homemade Console Pads, LED lighting "Ask an Expert" on Facebook I am not employed by Toyota, and the opinions expressed by me as a Prius Expert are not those of Toyota.

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11-22-2005, 08:01 PM	#1
syncmaster Senior Member Join Date: May 2005 Posts: 221 My Car: 2010 Prius Model: III Package: Thanks: 0 Thanked 3 Times in 3 Posts Friends: 0	How many times has this happened to you? You are waiting to pull out of a shopping center into fast traffic. You see a chance to pull out and floor it. The prius starts to take off and then the traction contorl kicks in because the wheel slipped a little and the the car hesitates a half second before it again tries to accelerate . I heard from a prius owner that he had a steep gravel driveway and he had trouble going up with the prius because the wheels would spin a little in the gravel and the traction control would keep cutting in. I am thinking about adding a switch so I can shut off the traction control. I think if you open the wires going to the sensors in the rear wheels that would disable the traction control but would the also disable the stability control? Has anyone tried it ? I would like to hear from others on this subject. Thanks for you input!

11-22-2005, 08:21 PM	#2
jayman Senior Member Join Date: Oct 2004 Location: Winnipeg Manitoba Posts: 11,865 My Car: 2004 Prius Model: Package: B Thanks: 47 Thanked 238 Times in 212 Posts Friends: 13	Well, that has happened to me too, especially on icy intersections. I don't think trying to disable the Trac is a good idea, you could destroy the power split device. I do wish Toyota had considered the climates the car would be operated in, and offered a "cancel" button that would desensitise the Trac algorithm. Otherwise you really do need good sticky studless or studded winter tires in winter.

11-22-2005, 08:41 PM	#3
ceric Senior Member Join Date: Oct 2004 Location: Fremont, CA Posts: 1,063 My Car: 2005 Prius Model: Package: #6 Thanks: 0 Thanked 45 Times in 17 Posts Friends: 0	I agree with jayman, what you really need is better tires at four corners. If traction is lost, w/o TC, the tire just spins. That won't help what you would like to achieve. Sticky tires for summer and snow tires for winters are the ways to go.

11-22-2005, 09:14 PM	#4
Tempus Senior Member Join Date: Feb 2004 Location: Washington DC Posts: 1,693 My Car: 2004 Prius Model: Package: #9 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	I agree with the previous opinions. Disabling Traction Control because your wheels are slipping is compounding the problem, not making it better. Yes, your approach might also affect Stability Control, and even possibly ABS. If you do decide to go ahead, be sure to cut the wires to the air-bags and disable your seat belt warnings just to be complete

11-22-2005, 10:57 PM	#5
Tideland Prius Moderator of the North Join Date: Oct 2004 Location: Canada Posts: 20,192 My Car: 2010 Prius Model: N/A Package: Technology Package (Canada) Thanks: 274 Thanked 419 Times in 284 Posts Friends: 23	I think it's cheaper to get a set of better tyres than replace the electric motors and/or PSD.

11-23-2005, 12:07 AM	#6
Mojo40 Member Join Date: Sep 2005 Location: Issaquah, Washington Posts: 61 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	The physics behind traction control are that sliding friction is less than static friction. In other words, a spinning tire get you less grip on the road than a non spinning tire. Now, this next part is not fact, but my interpretation (can anybody verify?) Traction control as implemented in the Prius does two things, 1) applies the brake to a wheel that is spinning, thus driving the torque to the other wheel that has a better grip, and 2) backs off the engine power until the wheels can grip. Here's the key point. Although the engine backs off on power to maintain tire grip, the Prius is probably giving you better acceleration than if the engine was racing and the tires were spinning. Again, this is theory, and I don't have data to back this up. I did read an article a few years back about this technology being applied on a two wheel drive Saab. It provided winter driving performance equivalent to an all wheel drive. As far as cutting wires - you have to be completely nuts to try and reengineer a sophisticated, highly integrated system like this. Just leave it alone. Go get an old VW beetle and reengineer that.

11-23-2005, 02:03 AM	#8
oly_57mpg Senior Member Join Date: May 2005 Location: Olympia, Portland, Seattle... Posts: 360 My Car: 2005 Prius Model: Package: #6 Thanks: 0 Thanked 2 Times in 2 Posts Friends: 0	Has anyone seen the post from Club Lexus about disabling vdis? http://clublexus.com/forums/showthread.php?t=187987 start the car with the parking prake on ....then foot brake twice....(keep the foot brake down)....then parking brake twice (keep it down )and repeat till skid light is on the dash

11-24-2005, 07:12 PM	#9
syncmaster Senior Member Join Date: May 2005 Posts: 221 My Car: 2010 Prius Model: III Package: Thanks: 0 Thanked 3 Times in 3 Posts Friends: 0	here is a link to someone having problems getting up their driveway because of Trac control. http://priuschat.com/Slippery-hills-vs-TRAC-t12883.html I copied this section from the posted link above, USE AT YOU'RE OWN RISK. to disable traction control on the prius: 1) Turn the car to ignition by pressing START twice without pressing the brake. 2) Floor the gas pedal two times (two full top to bottom pressings) 3) Make sure the Emergency brake is on now and put the car into NEUTRAL 4) Again press the gas pedal two times 5) Push PARK and press the gas pedal two more times 6) Now put your foot on the BRAKE and press START one time while holding the brake down. The prius will reset traction control to normal the next time you start it.