Traction Control Disable switch modification?

I am very interested in this. Will keep watching thread.

 

not a good idea. apparently, Toyota was concerned that if you have wheel spin and keep your foot in it, if it grabs suddenly you will break something expensive.

no question Toyota did a crap job on the traction control, but if you run better tires you won't lose traction so easily. I had 205/60r15 on my '04, and it definitely had way better grip than the pathetic junk integritys. I want to try 215's on my '06 but no $$ right now.

 

is this mod in the interest of spirited driving (autocross) or is the TC a nuisance in the snow or rain?

 

the TC is a nuisance all the time. any time you break traction, it will close the throttle for too long, and then you must wait or it will just do it again. its quite annoying. better tires will help a lot even for normal driving, unless you drive like a granny anyway.

 

The only way to disable TC without setting DTC's is to enter the car into "Inspection mode". This is NOT a good idea to do if you're going to drive the vehicle as the ICE will stay on. However, if I'm right, there is another way that should only cause momentary DTC's that would shift to "history" with an IG cycle. Wire a switch to one of the wheel speed sensor wires to cause an open in that sensor. When the EBCM sees an open in the seensor circuit, it'll turn traction control off. Cycle IG and the light should go away with only a history DTC. Test this out by just disconnecting the sensor with the car ready on and go for a spin.

 

I've had a similar idea, but instead the switch would cut off one wheel's sensor and connect the other in its place (from the computer's point of view). Then the car would see both front tires turning at the same speed. It might need to spoof the rear wheels as well, I don't know what the traction control uses to base its decisions on. I don't think it would throw any codes and it could be activated only when necessary.

 

and if you get rough with it, you'll need to replace the transaxle when it breaks. not a good idea. better tires is the best choice.

 

So don't get rough with it.

The '06 Escape Hybrid I had before my Prius didn't have traction control. It would light up the tires at will, but I can't remember seeing reports of many (any?) transaxle failures. I doubt the Prius' transaxle is made of glass in comparison, but I agree that a bypass like this shouldn't be used for autocross.

 

I do not know how the escape was set up, but from what little I understand about the prius tc, I believe that Toyota did it that way because if you got it floored and it slips, revs way up, and then grabs hard, it could break the planetary or something. being poor, I know I don't want to ever have buy or replace the transaxle.
if you ain't floorin' it, you ain't drivin' it. its not as slow as my 300td was, but it shaped like a turtle for a reason.

 

Think about this, when your wheels start to slip, the TC cuts power to the wheels and they grab. Why doesn't anything break then? I don't think anything will happen, so long as you're not being malicious and/or mischievous. For the sake of getting unstuck, I think it'll be ok.

 

and yet, no one has done it.

 

it doesn't break cause its not revved up. if its revved way up and then grabs hard, its just like dumping a clutch. and drag racers back in the day would break stuff when they dumped the clutch. which is one of many reasons they all use automatics now.
another example- friend of mine put a chevelle in neutral and revved the motor to like 5000 rpm foot to the floor jammed it into drive, and broke the pinion gear in half.
when you have anything spinning at full speed and then stop it suddenly, somethins got to give.
if your going very slow, I guess it wouldn't hurt to have the tc turned off, but if you forgot it was turned off and floored it, could be ugly.

 

The reason they use automatics now is for a couple reasons.

Trans brakes, no mis-shifts, shift harshness adjustments, no hard clutch pedal, and speed of shifting is faster on automatics.

So you're comparing the prius to some v8 muscle car with gobbs of torque. Probably at least twice as much torque as the prius can generate. I understand what you're saying about revving it way up and then it catches. Read my post again. Last two sentences to be exact.

 

right. now re-read the last sentence of my post, and the earlier post. since this car is slow, sometimes you got to floor it. I know why you don't like the TC cause I break traction constantly, and then wait...
I will be getting some better tires and wheels next year which will help alot.
but you got to realize Toyota did this for a reason, and not just to annoy us.

 

My point exactly, if you need the ability to disable it, then you should have that ability. They make lights come on when TC is turned off and if you disable TC with a switch on the speed sensor, then TC won't be functional until the ignition cycles. So why would you forget TC was off and not pay attention to dash lights?

My theory behind why the TC acts the way it does is, because the electric motor. Motors give 100% torque as soon as they start spinning given full power (AKA: full throttle for the prius' sake). This gives it a sudden and immediate spike in full available torque. Of course it'll spin the tires, so a governor was put in place to watch over wheel spin. I , too, don't agree that it should be as strict, but I learn my vehicles limits and I learn to not cross them if I don't need to.

 

but since the integrity tires suck so bad, its just about impossible not to break traction unless you drive like a granny. when I had better tires-- which went with the '04 when I sold it-- this was less of a problem. these sucky integritys squeal if i take a corner at any decent speed. if there's the slightest bit of moisture, sand, gravel, etc. they slip.

why would you not pay attention to dash lights? how many folks have blown an engine cause they kept driving after the oil or temp idiot lights came on? happens all the time. of course, those folks are all idiots and wouldn't have the intellect to buy a prius in the 1st place. right?

 

I would hope they wouldn't. Lol. Idiots is spot on.

I just put over $10,000 worth of brand new engine parts in a highlander because the driver didn't notice the temp gauge went hot, heard a noise, saw steam (she said smoke), and kept driving because the noise and smoke went away and the temp gauge then read cold. She wound up warping both banks block and heads far beyond specs to be salvageable. As a reference, the engine got hot enough to MELT the knock sensors. That's a stock car and I doubt anyone installing a TC inhibit switch wouldn't know what the lights meant, but there are smart idiots out there (the worst kind of idiots).

 

well good luck if you can figure out how to do it. just post a disclaimer when you do a write up on the switch mod