Traction Control System (4th Generation)

[904-DUVAL-SR5]

Could anyone here please help explain to me the way the Traction control system works? I was going through a little mud the other day for the first time and my TCS came on and it felt like it wasnt giving it any gas at all? I had to fully brake then start again cause it felt like the wheels werent moving when I was gasing it. Does it help having it on-even if you are going through mud? Is there any way to turn it off??? Cause Im definatley used to gasing it like hell and spinning tires like crazy to get out of mud. Or do I have this all wrong?

 

[swimmer2361]

That is VSC not ATRAC. VSC senses that you are slipping and mistakingly thinks you are loosing control of your car, so it cuts engine power and breaks individual wheels in an attempt to get the vehicle straight. Locking your center differential disables VSC so it wont cut your power if your stuck in mud.

I recommend reading this A+ article written by Thai that explanes how ATRAC and VSC work.

Link

 

[Koz]

When in mud you would want to lock the center diff, this will disable VSC. The traction control is still enabled. The traction control will pulse the brakes to direct torque to the wheels with traction. Mud is a very tricky problem and creates havoc with ALL vehicles.

Koz

 

[G.I.G.]

I recommend reading this A+ article written by Thai that explanes how ATRAC and VSC work.

Link

I was reading through that article again and I wanted to verify something with people in the know.

With a 4R V8 4x4, can you lock the center diff and disable VSC in 4 hi? I thought I read somewhere that can only be done in 4 lo. The article mentions that you can lock the center diff in 4 hi but that is with the V6 with multi-mode.

 

[Falls]

You can lock it in both 4hi & 4lo to disable VSC.

Atrac is always activated as far as I know and it great for real tough situations. Great feature off road IMO.

 

[Thai]

Mud is quite tricky with ATRAC. ATRAC does slow you down a bit in mud because the ABS brain will be braking/slowing down your tires on and off in order to transfer the power to the appropriate wheel(s). Therefore, i would definitely get a bit of momentum (if possible) going thru the mudhole. You probably should NOT stop in the middle of mudhole.

As stated above, you MUST lock the center diff if you're going thru mudhole. This will do two good things:

1. Turn off VSC...and yes, this applies to both Hi and Lo range.

2. Prevent transfer of power back and forth between front and rear axles (via Torsen center diff). By locking the Torsen center diff, you are making sure that power goes to both ends equally and all the time. Less variation in power flow = better traction.

I don't know about other people's experiences, but i am almost always in 4-LO while off-roading. 4-Hi is mostly for going thru washboards at high speed. When i had my 4runner (2002), i could swear that ATRAC was more responsive (aggressive) in 4-LO as opposed to 4-HI.

And, remember, above 3000 rpms or so, ATRAC decreases it's intervention, allowing you to make a "rooster tail" or power up an embankment.

So, the keys to ATRAC are: (LOCK CENTER DIFF when off-roading)

1. Keep your speed consistent...don't be chicken to push a little deeper on your gas pedal. ATRAC is not at it's best when you're crawling really really slow. Why? Because ATRAC has to detect wheel slippage (aka difference in wheel speed between two wheels on the same axle) before it can intervene and brake the slipping wheel.

2. For rock crawling, you need ATRAC. Therefore, keep your foot on the gas pedal but try and avoid gunning it. I would stay below 3000 or so rpms.

3. If you're in mud or sand or need to power up a mudhill, then i would be more aggressive with the throttle. As soon as your momentum slows down, i would push harder on the gas pedal and keep my rpms above 3000 (but do NOT redline it!) because in these instances, ATRAC can hinder your forward progress. Remember, ATRAC lags behind actual traction because it has to wait for slippage. And in mud, the wheel(s) with traction changes every second. In addition, by revving it a bit, ATRAC decreases it's intervention and allow you to get power to all 4 wheels (with or without traction).

4. Do not pay attention to all the weird springy-dinky noise coming from underneath your vehicle...that is ATRAC doing it's thing. And try to avoid the urge to lift off the gas pedal when you hear these noises. This will cause loss of momentum and ATRAC does not function very well if your wheels are not spinning.

Go out and try it out. The above statements are from my experience with my '02 4runner.

Have fun.

 

[904-DUVAL-SR5]

So can I lock the center diff the whole time Im off-roading( if its mostly mud)? And it wont mess up my car??? Or should I lock the center diff only when I come upon a mudpit?

 

[swimmer2361]

Well I usually lock my differential only when I need it. If the trail is mostly mud it would probably be safe to keep it locked most of the time.

 

[Thai]

I would lock the center diff most of the time, esp. in mud or sand. Remember, it's pretty hard to bind the center diff on any slippery surface. The only time that this is a problem is on dry land.

For me and my G500, i lock the center diff at least 90% of the time.

 

[JB.]

When i had my 4runner (2002), i could swear that ATRAC was more responsive (aggressive) in 4-LO as opposed to 4-HI.

Well, the 4th gen is like that so I'm guessing it was no illusion.

So can I lock the center diff the whole time Im off-roading( if its mostly mud)? And it wont mess up my car??? Or should I lock the center diff only when I come upon a mudpit?

Depends on a what you prefer, you certainly can lock it all the time off road if the surface allows some wheel slip. I used to lock it all the time when going slow off-road. I now prefer to have the steering feel of being unlocked until I think locking is in order but I don't do much mud. As far as mud, as mentioned above, the ATRAC is more aggressive in low range so if it was higher speed mud on level terrain, you should lock the diff but might want to stay in high range to get less intervention from ATRAC. Running in 1st high, center locked seemed to work well for me on sand dunes, for instance.