RSC and traction control
 

My 2007 Expy is slowly driving me insane with the rsc and traction control. I like many others I'm sure know how to drive in inclement weather without the computer taking control of my vehicle. Is there anyone that knows how to disable the rsc and traction control. Not the fake hit the switch way. That only temporarily disables it, and only under 25mph. If I'm in deep snow losing momentum I would like to keep the tires spinning in the snow or mud. The engine losing it's power and brakes having a mind of their own is a source annoyance to me. Anyone please help. It is bad enough that limited slip differentials are no longer available on the XLT's and above.

I don't believe that there is any way to permanently disable it because it is required by Federal Motor Vehicle Safety Standards. That is why the AdvanceTrac w/ RSC button allows disabling to occur only below 25 mph. Electronic Stability Control will save between 5,300 to 9,600 lives and prevent 156,000 to 238,000 injuries in all types of crashes annually once all light vehicles on the road are equipped with ESC.

With AdvanceTrac w/ RSC, there is no need for limited slip differentials, the brake applied on the slipping tire works way better at tranferring torque to the non-slipping wheel than any LSD.

The Owners manual has a way to solve your problem on page 262. If you press the AdvanceTrac w/ RSC button, you disable engine power reduction and get only brake application on the slipping tires. As stated above, this actually performs better than a limited slip differential, and it will do it on both front and rear diffs.

If you press and hold the button more than five seconds it disables brake application, too. But, then you would have open diffs front and rear making acceleration in snow more difficult.

I don't know, but I found out early that you can't drive this 07 like cars and trucks of the past I have owned.
The first time I made a left turn out onto a busy four lane highway giving it the gas expecting some tire spin and some sideways sliding controlled by just letting of the gas a little, I almost spun all the way around the other direction in to oncoming traffic when the traction control took over.
I thought I was going to roll it over before I could get it to quit hooking up by letting of the gas. Letting of the gas did not seem to help like you would think. It just kept trying to hook up.
Normally even with positrac or a locker this is not a problem as you just let of the gas some until you get going straight.
So now I have learned to get going in a straight direction before giving it the gas.

It is like the first time I used ABS brakes, I thought my world was coming to an end early the first time I had it kick in. I was not expecting it.

I drove a 73 T Bird with a positrac for twelve years in more mountain snow storms than I could count. Never once had a problem with getting stuck. Like driving a tank.

I will take a good old locker any time over "traction control".

It is hard to teach a old dog new tricks I guess.

Rich 93 cw I hope it is true that "Avance trac/RSC" will help to save lives more than any body, but some times I wonder where the line is drawn between the driver and the car or truck.
At some point the car can't save you. Sort of like air bags. I am all for them, but then again I think it causes some people to think that there is there is no danger in driving.
Driving a car or truck has more hazzard than any thing else a person does in a 24 hour day unless you have a job with the bomb squad or the like.

Some where I seen in a newspaper that we would all be better drivers if automakers were required to have a big sharp spike sticking out in the center of the steering wheel. I agree.

Above I talk about driving my old 73 T Bird (the tank) with posi trac 12 years through some of the worst mountain snows you could think of and never got stuck once.
However I was always amazed how many cars and trucks I would drive past that were stuck in a ditch, wrecked, even upside down. Even more amazing was that about 75% of these were 4X4s.

How is it I am driving my 73 T Bird two wheel drive in a snow storm past a upside down new 4X4 Chevy Blazer? I would like to think it has something to do with the driver of the T Bird and not just luck alone.

I guess what I am saying is I would rather take my chances with a positrac and some good (hope) driving than a government mandated computer controlled traction control.

Also after driving through 30 years of Colorado snows as odd as it seems I agree with moonunit7317 that in heavy snows some wheel slip is a good thing to have.
If on ice or light snow, lots of traction is a good thing, with studded snow tires even better.

However in very heavy snows a lot of traction with out some wheel slippage can get you stuck if it won't let you keep the engine RPM up. This is why chains on a underpowered truck or car can get you stuck in heavy snow. Too much traction.

This is where the 73 T Bird (the tank) would really shine as although it was only 2 wheel drive with posi track it had a big 460 V8 that had the power to plow through heavy snows even with chains on while going up grade like a real trooper.

The ability to keep moving is important and if that means some wheel slippage to do so then it helps by keeping the engine in its power band even with low range. If the engine over speeds a little at times during wheel slippage it will come back down when traction is regained so it is ok because you are still moving foward.

If some "computer" device sees the engine RPM up with some wheel spin (now your speedometer is way up there over 25) and cuts your engine RPM back plus starts messing around with the brakes with the idea of regaining traction while in heavy snow, your are going to be stuck.
I would bet on it.

Some of my responsed are placed within your quote.

That reminds me of an event that happened to me similar to the one that you described in an earlier post. You said that the ESC began to work when you were accelerating and turning from a stop, and that it would go on and off and eventually you began doing donuts.

About five or six years ago when I was testing ESC technology on three vehicles, an M-B ML360, a Lexus LX470 and Lincoln LS, I had the same experience on all three. I even got the ML 360 up on two wheels and the outriggers! The course was a 40 mph. double lane change and then a sweeping decreasing radii turn. I spun out alll three witht he ESC activated, and completed the maneuver on all three with it off. The test engineers were shocked that I was able to elicit such bad behavior with the ESC enabled. At first, they thought that they must have had it off. On the second try, they said that I was entering the test course at over the 40 mph, limit. On the third try, they believed that I could make it misbehave. During the test session, we never did figure out what happened.

Fellow NHTSA people there cheered me for having gotten a vehicle up on the outriggers and suggested that I would make a fearless autocross driver. I said that all I did was to do what they told me to do, and I was sure that they would have made the testing safe for mere NHTSA engineers to participate (hopefully, ESC would be safe enough for even the public!) Anyway, in hindsight and a few hours of talking and thinking back at the office, we determined that I was actually trying to drive the vehcile through the course (and using throttle to do that rather than heavy brake application.) Apparently, as you tried. Well, you just can't keep your foot on the acc. pedal when the ESC light is on. It will do exactly what yours (and my test cars) did. It will try to slow the vehicle with power reduction and braking, but you and I kept telling it, No, I want to go faster!, by keeping our foot on the acc. pedal. The best that it could do was to respond, but it couldn't keep up. We kept telling it that we wanted to go at a speed that was much higher than safe for the conditions and it kept trying to prevent that. Well, we won and spun out! The same thing would have happened to most drivers in a rear drive vehicle without ESC. Bottom line, some drivers are much skillful or have much more experience than most drivers and will be frustrated by ESC. The bottom line is that when ESC is operating, the conditions are dangerous for travelling at the speed and maneuver trying to be done. For a few drivers, the threshold is higher.

Bottom line, below 25 mph, you can turn it off completely, but you will be without limited slip functionality; over 25 mph, if it operates, it will be telling you to go much slower because the conditions are bad for most drivers - lay off on the gas.

How does the braking system transfer torque? For that matter how does an open dif transfer torque to the other wheel while the slipping one is being slowed by the brakes?

Just a question about what electronic traction control really does.

Wow, great information, thanks. I have learned to not give it the gas until I get it lined out first or it will try to "take over". It is that I have been driving too long I guess and have learned to find out first so I know the limits of the car or truck I am driving and then drive it within those limits. I understand most people don't.

For example how many people find a road with no traffic and running about 20 to 25 MPH turn off the ignition to see what is like to have no power steering or brakes? I would bet less than 5%. I had my wife do this and she responded by freaking out standing on the brakes going all over the road. If this was done while in traffic I don't know what would have happened.

My uncle Chet ran his 59 Chevy into a bridge railing between Springfield and Walsh Colorado @70 MPH during 1963, He finally died at the hospital. But before he died he said that the steering and brakes went out and he lost control of the car.
When the car was checked out the only problem they found was that it was out of gas causing the engine to quit, causing the loss of power steering and brakes. I remember this even today.

I also showed my wife something simple that I have always done since 1965 In my Drivers Ed class, we learned to when driving on the highway which usually works better than on a lower speed street to let go of the steering wheel just for a few seconds to see what happens. Many times if you get a pull (provided you are not out of alignment) you may have a tire going low. I do this all the time and more than once found a low one as you can pick up a nail or something at any time while driving no matter how many times you check your tire pressure.
But my lesson did not go very far I guess because my wife was calling me on the cell phone telling me that a tire on the Bronco "exploded" on the highway @ 60 MPH. Later during further "discussions" it seems that the Bronco seemed to slow down causing my wife to keep increasing the cruise control. I think the "exploded" tire picked up a nail went low, got real hot and then "exploded" after seeing all the burnt, melted rubber inside the wheel well, down the side of the Bronco.
Lesson not learned, a new tire with about 200 miles on it shot. It is a wonder there was not a wreck or something.

I still do this on the 07 even though it has the tire pressure sensors. Old habits are hard to change.

They told us in Drivers Ed to expect the unexpected when driving. Very true I have found.

Response to Rich93cw as to speed in the snow. Actually in deep snow I am talking about you are only going about 10 MPH or so, but due to wheel slip you might see the speedometer showing that you are going 35-55 MPH or so at times. I think this is where the "computer" sees this then takes over above 25 MPH and causes problems discussed in the original post.
I understand the 5 second button, but I am talking heavy duty snow in Colorado at 9000 feet, in my case three miles of it. I would wear out my finger pushing that button.
By the way I now live in Las Vegas NV. where it only snows once every three years. So I may not ever get to use the 4X4 function. My button punching finger feels better already.
May be Moonunit could provide more details on this.

Don't some systems turn off the traction control in 4wd?

I don't know, but not sure. With out a locking diff it seems that without the "traction control" playing around with the brakes you would not have anything but a regular open diff even in 4x4 mode.

All this computer traction control stuff is new to me. In the old days I was the "Computer traction control" as my "computer" would say "OK well I got Posi trac and studded snows but click, buzz, sensor input from eyes, buzz click , wow look at all that snow, buzz, click buzz, compute, beep beep beep, better get out the tire chains" or something like that.

I mean now they have cars that parallel park themselves by computer control. I seen it on a TV commercial. Try explaining that to a judge in court that "I did not run over that guy while parking" "my car did". Geee whiz, what next?

It is!? Do you have a source for that info?

The Expy does not turn it off in 2H, 4AUTO or 4H, but you can. Also, in 4L it automatically turns off all stability and traction control, except the brake traction control, however you can do that manually if you want to loose almost all traction because of two open differentials (p. 276 and 277 in Expy '07 Owner's Guide.)

Pages 274-277 have a wealth of information to answer all your questions about 4x4 and AdvanceTrac W/RSC.

Acceleration traction control system uses engine power control and individual brake control to improve traction. The engine control is obvious, in that lost traction means too much force is being applied to the tire and it is slipping. Slowing it down by reducing engine power will help it gain traction again. In an open differential, when a tire spins, all the engine power is being applied to that spinning tire and the stationary tire is just going along for the ride. You can demonstrate this to yourself by jacking one tire of a open diff. axle off the ground and rotating that tire. Make sure that the front wheels are blocked and that the parking brake is off and the transmission is in neutral. What happens is that your turning the tire will easily rotate the driveshaft. When that tire is slipping because too much engine torque is applied to it, the reverse of what you experienced is happening. Only the spinning tire has engine torqued applied to it. By applying the brake on only the slipping wheel, brake traction control will constrain its rotation so that a large proportion of the engine torque will go to the non-rotating tire. (You can also demonstrate that to youself by rotating the drive shaft by hand, have someone stop one of the rotating tire. Instantly you will not be able to turn the driveshaft because you are now trying to rotate the tire that is still in the ground. All your effort is going into trying to turn that non-rotating tire. This is actually better than a limited slip diff. because the best that you can get in a limited slip diff is half the torque to each tire with each tire's rotational speed being identical. In the brake traction control, you can get up to 100 percent of the torque because the brake traction control can actually stop the slipping tire from rotating if is has no traction at all. You can see this happen in the current Mercedes Benz commercials where they keep asking how often do you do extraordianry things with you Benz. At one point you will seen a Benz travelling over a very rough terrain where one of the tires is completely off the ground. Suddenly is stop rotating. That is brake traction control working. If it had not had that but a limited slip, it would have turned at the same rpm as the other tire on that axle, splitting the torque between the tire with traction and the one without traction. Granted, the one with traction would have gotten the lion's share, but it would not have gotten all of it, as would have occurred with brake traction control.

Ford does caution, on page 261 of the Expy '07 Owner's Guide, that brake overheating is a possibility during traction control, and that the system will sense that. If the traction control system is using both engine and brake control, the engine control will still function, but the brake control will cease until cooled down. The disabling of the brake control, however will not occur during a situation where ABS, RSC or ESC is needed, even if the brakes are overheated.

Here is a summary of the law: http://frwebgate2.access.gpo.gov/cgi...ction=retrieve

Here is the full law: http://frwebgate2.access.gpo.gov/cgi...ction=retrieve

For an full explanation of why, read this: http://www.nhtsa.dot.gov/staticfiles...%2003_2007.pdf

For information about how ESC works and what vehicle have it, see: http://www.nhtsa.dot.gov/portal/site...3ab10cba046a0/

I believe that you need to push the button only once unless you turn the ignition off.