Disconnecting Traction Control

[begs Junior Member Find all posts View Profile Close begs]

Re: Disconnecting Traction Control

By its very nature I would consider traction control a disadvantage in soft sand. It applies the brakes to wheels that lose traction but in the sand you want them to keep spinning so you don't lose momentum. Having said that I did leave it on most of the time up at Fraser and didn't really have any issues. In long stretches of deep sand I would look to engage the centre diff lock to keep a consistent drive through all wheels.

This probably opens up further debate on general off roading. Where to use traction control and where to lock the centre diff. I would think that in a steep climb on loose surface the traction control would be excellent. I have really tried this myself yet so only guessing. Same goes for deep rits and uneven ground where you woudl be consistently lifting a wheel.

Are there any other times where you would engage the centre diff and not use the traction control?

Just to clear something up. Traction control is still on when the centre diff is locked, at least on the 2008 models. When you turn on the centre diff the vehicle stability control is disabled (VSC), but certainly not the tranction control. I haven't had any problems in the sand, but I haven't really driven on anything too soft, but I can see that it may cause a problem.

I have had the traction control kick in on some loose steep rutted stuff (low range centre diff locked), and it really helps. Without the centre diff locked you only need to loose traction on one wheel and you could run in to problems. With the centre diff locked you need to lift two wheels (front and back). I would be locking the diff on anything that has a loose surface, and especially when there are ruts and where you're lifting a wheel.

Cheers,
Ray.

[DocK Member Find all posts View Profile Close DocK]

Re: Disconnecting Traction Control

I have recently done the Robe Beach run with a mate who has a Prado D4D GXL - no TC. On one of the steeper soft dunes my first run in the VX (TC equiped) would not make it up but the GXL did - my wheels braking his wheels spinning. Made it on the second run with a little more momentum. Mind you an old 3L turbo diesel Hilux took 10 runs! If fuse 55 is sitting there for the TC couldn't a manual switch be wired in and operate the TC from the cab when needed? Just like the centre diff switch. The flip side is when in the Flinders the TC came into its own with the rough, loose and rutted surfaces and got me thru some awkward sections at much gentler speeds, so not risking vehicle damage and family panic.

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

Re: Disconnecting Traction Control

We have just returned home from a couple of weeks of sand and beach driving on the Fraser Coast. Took the opportunity to do some experimenting with VSC, TC and diff lock in our 120. First thing I noticed was that sand tracks that I used to do without the centre diff locked in my 90 were "harder" in the 120 because the VSC and TC kept interrupting the drive when one wheel spun a little. This was very disconcerting to say the least and the first time it happened I was pulling our trailer and I thought I was going to come to a grinding halt on an easy track. How embarrassment! ops:

But I did learn that locking the centre diff which according to Mr Toyota should leave TC in play solved the problem. I found that with the centre diff locked the TC did not cause us to lose momentum even when it was working and more importantly the engine was not de-powered by the VSC at the worst possible moment. TC did not impede us in any way as long as the centre diff was locked.

I discovered another thing that is worth pointing out to anyone like me who is new to automatics on the sand. Apart from the obvious lack of engine braking there was another effect I was not aware of. When you back off the throttle the gearbox can actually get confused about what to do. If you back off because you are coming to a firm (and usually rough) bit of ground after working the engine over soft sand the gearbox can actually change up a gear because of the reduced load on the drivetrain so instead of slowing down the car actually speeds up! Easy to fix by locking the auto in the appropriate gear but the first time this happened I thought I must have brushed the go pedal by mistake. That said the auto in my opinion is far better to drive as it allows lower speeds and lets the engine torque work better. Not sure about DocK's experience but I found that the 120 is a different drive to the 90 and that meant I have to relearn a few things but that is ok! More playtime!

Michael

[DocK Member Find all posts View Profile Close DocK]

Re: Disconnecting Traction Control

Found that interesting Michael - I guess I forgot to lock the centre diff. Oops :? Looks like I had better go down there just to try again - Any reason for a beach run I suppose!

[pico Lurker Find all posts View Profile Close pico]

Re: Disconnecting Traction Control

Guys,

I'm struggling at something or both of my Prados are broken. The shift lock button doesn't work!! is tghat the same as diff lock?
Can you lock the diff lock in normal drive mode? I thought it was only when in low range...
As you can see a bit confused!!!
Any insight?
Pico

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

Re: Disconnecting Traction Control

Pico I am assuming you have an automatic with the separate button for locking the centre differential. Otherwise the stubby lever locks the centre diff when you go from H to HL (high range locked centre diff) to N (not going nowhere) to LL (low range locked centre diff). With the automatic and separate centre diff lock button the diff lock button can be pressed any time in any gear in any range up to 100 kph (I think). I know because she who must not be named accidentally pushed it while putting a phone on charge and we were doing about 100 on blacktop. Dash light flashed and then went solid to show the diff lock was engaged. Luckily we were travelling along a flat straight road so I just switched it off again. No transmission wind up or damage.

However it seems you are talking about the shift lock button which is a different animal entirely. The shift lock button is used to override the lock out that prevents you from changing the transmission out of P without the engine running/brake pedal depressed. The only time I have ever used it is when I push the car around in the garage and I am too lazy to get the key (too lazy to walk 30m to get the key but ok to push 2.6 t around a concrete floor?).

Some people have found that they were unable to shift from P even with the engine running and foot on the brake and then they had to use the shift lock button to override the lock out. There are several threads about the shift lock button and the first thing to look for in this scenario is a blown fuse.

If you have two Prados with the same symptoms I am guessing that it is operator not vehicle. Sorry. It sounds like you are using the shift lock button for some other reason. If not then you likely have a different issue. Are you able to select gears with the engine running and brake on as normal? Is it only the shift lock button that doesn't work? That is you cannot shift the transmission out of P using the shift lock to release the lock out mechanism with the engine switched off?

If the car(s) is still covered by warranty take it back to Mr Toyota. Otherwise it would appear that the shift lock button(s) has a broken detent or something similar preventing it from being used.

[timmy Junior Member Find all posts View Profile Close timmy]

Re: Disconnecting Traction Control

I have just purchased a 2003 Grande.

I experienced problems in soft sand today. I thought I could exit the beach very slowly with VSC and found the vehicle beeping and carrying on. Then engine power dropped and left me one foot short of the hard surface. I ended up having to gun it up the track. I thought the traction control would enable me to take it slow as it would afford power to the wheels with the most traction. I guess in sand all the wheels are spinning so the engine just powers down (and in this case left me sitting there looking like a fool that didn't know what he was doing)

I am confused with some of the posts and prado manual regarding Traction Control and Vehicle Stability Control. The manual describes Vehicle stability control;
The vehicle stability control system helps provide integrated control of the systems such as anti lock brake system, traction control, engine control etc.... The engine automatically controls the output of the brakes or engine to help prevent the vehicle from skidding when cornering on a slippery road surface or operating steering wheel abruptly

Then on page 48 it says regarding the VSC off button;
Pushing the Center differential lock switch automaticly turns the vehicle stability control system off.

Now I went back to the sand test the difference between having the VSC off or on and I found it turned off everything but the ABS brakes which I thought WERE part of the VSC system as described in the manual. I found I could spin and slide the prado with no loss of power and no stupid beeping and spring sounds from the vehicle.

Can anybody tell me exactly what is going on with the descriptions of VSC and Traction control. Also can someone explain exactly what center differential lock is/does i noticed in the manual there is a switch for rear diff lock that my model does not have. Is this an extra option and why would you need one if the center diff lock is available.

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: Disconnecting Traction Control

Can anybody tell me exactly what is going on with the descriptions of VSC and Traction control. Also can someone explain exactly what center differential lock is/does i noticed in the manual there is a switch for rear diff lock that my model does not have. Is this an extra option and why would you need one if the center diff lock is available

VSC (Vehicle stability Control) and TRC (Traction Control) are two completely different systems with different design outcomes, however they are related in hardware and electrically (Both are ABS based)

VSC is a safety feature designed to help you maintain control of the vehicle in a situation where usually you might not be able too (it prevents over and under steering at speed which result in loss of vehicle control)

Traction control is there to assist you either off road or in very low traction situations. It prevents wheel spin, in a nut shell, by applying the brake on any wheel that spins.

The center diff lock turns your AWD Prado into a true 4wd. In AWD (On road use) you need to have an open center diff to allow for different speeds between front and rear axles (when turning), this is less than ideal off road however as there is still a traction compromise. When you lock the center diff you have a true 4wd in that you have a 50/50 torque split with no difference in axle speed possible, this is for off road only, drive on road/high grip surfaces with the center locked and you will cause "transmission wind up" where the stresses caused by the front at rear covering different distances when corning can't escape. This will cause accelerated wear in your drivetrain and possible component breakage.


The nature of how differentials work mean that if you lift two opposite wheels in an off road situation then the vehicle will stop moving forward. This is where rear diff locks come into the picture (they can also be fitted to front axle diffs). A rear diff lock basically locks the two rear wheels together thus meaning when cross axled as described before the one wheel still on the ground will continue to drive the vehicle forward. Factory rear (and front for that matter) were not available as an option in Australia on the 90 or 120 series. They are available as aftermarket fitment only.

Mick

[timmy Junior Member Find all posts View Profile Close timmy]

Re: Disconnecting Traction Control

Thanks Mick, Great explaination I figure I will be doing beach work with the diff lock ON mostly from now on.
My last 4x4 was a 98 Jeep Geand Cherokee. Constant 4x4, and no diff lock but seemed to handle the soft sand okay. Different system I guess.
Much happier overall with the prado, and this site is such a help in so many ways.

Tell me is there a thread that shows more detail on how to use Pradopoint website in full.
Like how do you add the details of your rig or quotes at the bottom of your posts? Do you click the post reply at the bottom of page (as i have done here) or 'quote' reply with quote next to a persons post to reply directly to them?

Or how about creating a thread!... I have read 'The Rules" by team piggy and am wanting to negotiate the site properly.

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: Disconnecting Traction Control

Constant 4x4, and no diff lock but seemed to handle the soft sand okay. Different system I guess.

The constant 4x4 version of the Jeep uses the "QuadraTrac" system (Jeeps name for it)... it locks the center diff automatically when required.

There is a short cut to the FAQ section on top right hand side of the page, under the search engine. Or follow this link:

http://www.pradopoint.com/faq.php

The FAQ section should answer most/all of your questions :wink:

Mick

[Justo Advanced Member Find all posts View Profile Close Justo]

Re: Disconnecting Traction Control

There must be a TC variation between Prado's. I have never had a problem in soft sand with the TC, one beach I was down to 8psi tyre pressure to get out but at no point was there any issue with TC overriding.! Even steep climbs etc theres no issue.. I would go as far as to say its tyre pressure and right foot pressure to blame.. :lol:

[FlyNdrive Advanced Member Find all posts View Profile Close FlyNdrive]

Re: Disconnecting Traction Control

Here is how to disable the traction control in an FJ Cruiser. since it shares the same components it is possible that this can do the trick. if not it is completely reversible If any PP'er wants to try it.

Here is the link for when the pics are removed. http://www.fjbruisers.org/forum/inde...1.0#quickreply

-Ben

[quote author=Trevor Criste link=topic=1391.msg22234#msg22234 date=1210527459]

NOTE! to turn the TC back on you need to turn off the engine and restart

first pop the hood and locate the TC harness shown here. (note: in the pic the new wires are already spliced in)


second pull the rubber cover that surrounds the two free wires that go into the harness, find and cut the purple
one.


grab about 6 feet (3 for each way to and from the switch) of wire and run it through the fire wall here to a toggle switch.


Dave (Medic Mechanic on the Bruiser forum) made me a fancy switch in one of the blank fj tabs and soldered everything together


big prop to Dave i was talking to him about this and he said "show me" and the next thing i knew i was watching the master at work in awe that it took him maybe 5 minutes to do. THANKS!

[/quote]

[OhWhataFeeling Lurker Find all posts View Profile Close OhWhataFeeling]

Re: Disconnecting Traction Control

Just to add to the conversation above. I recently had need to run my 2005 V6 petrol Prado VX whilst on car stands. I put all 4 wheels off the ground (made very sure the stands were secure) depressed the difflock button which disabled the VSC (the dash light came on showing it was disconnected) put it in drive and slowly built up the engine (and wheel) speed. Out of interest once above 40km/h I tried to set the cruise control. I can attest that it engaged and I built up the wheel speed to about 80km/h (very nervously shadowing the brake at all times) It ran for a while but eventually one of the wheels must have gotten out of synch with the others and the traction control cut in. It released the cruise control (makes sense) and the wheels slowed back to idle.
Now the VX doesn't have LSD it has "open" diffs front and rear.
The interesting thing is that the centre diff lock does disable the VSC but does NOT disable the traction control.
Also interesting is that the traction control automatically shuts off the cruise control when it cuts in.

It was an interesting experiment.

[paulyc Member Find all posts View Profile Close paulyc]

Hi all, digging up an old one.

I recently had this issue with TC in soft sand. Was just wondering if anyone has had any issues with driving when the fuse is pulled out? And any issues when the fuse is replaced after finishing on the beach?

Also has anyone tried or installed a switch in the cabin like was done in that post on the fj.

Thanks, Paul

[macaroon1 Advanced Member Find all posts View Profile Close macaroon1]

This member did: http://www.pradopoint.com/showthread...l=1#post449156

Not sure exactly what he did. Pulling out fuse 55 under the bonnet seems the go but never tried it!