3rd Gen Traction Control Modes Explained

Alright, I just did some testing on my lunch.

I found some pids in the abs section on obd fusion. The upper left was supposed to be gear position, disregard this box. The upper right is traction control ENGINE. The middle left is traction control on or off. The middle right is traction control BRAKES. Disregard values, numerically, of all boxes. Just note that there is a value.

The bottom left is the traction status box. Values are as tested.

2WD
Normal = 0.0
Short push vsc = 4.0
Long push vsc= 6.0

4WD HIGH
Normal = 0.0
Short push vsc = 2.0
Long push vsc = 6.0

4WD LOW
Normal = 0.0
Short push = 0.0
Long push = 6.0

Notice auto lsd has a different number from 4wd high range trac on vsc on. But in the pictures the test values are the same. HMMMMM.......

Also take note that there is no engine regulated traction control active in 4WD HIGH range. Test was performed up to about 2100 rpm. Traction control starts to kick in on average around 1200 rpm.

Edit....
The only mode where I felt engine regulated traction control was 2WD stock no vsc button press.

My test hill.


2WD FULL TRACTION CONTROL, engine and brakes


2WD AUTO LSD


4WD HIGH TRAC ON VSC ON


4WD HIGH TRAC OFF VSC ON


4WD LOW TRAC ON VSC OFF



What’s does all this mean?????? I’m sure we will all find out together. I still need to test 4wd high, traction control, engine regulation, at high rpm but I’m about 99.1% sure it doesn’t exist.

PB

 

Wow!

There are a bunch of new developments near me that would have made testing easy, but I didn't want to risk pissing them off. Most of them are past the developer stage. I wanted to ask a developer if I could mess around.

Great results though! It's hard to tell from the dirt pic, but was the LSD modes moving you forward?

 

I’m on a very large site and the supers know me well, no hooning, just testing.

When traction control was on in all modes the truck was pulling forward breaking traction, sliding backwards, or turning all tires digging holes.

 

Exactly. Back in the 90s, I worked road projects that destroyed my old Chevy Celebrity (first car). It would have been the prefect place for the Taco. That's all that the survey guys had.

No hooning was going to be my excuse if anyone asked while I was on that loading ramp. I keep thinking about how you'd explain what we are trying to do to anyone:

"Well, occifer, I was just trying to see why our trucks have, like, 52 modes. Ya know?"

Ummm, son, can I have you breath in this tube?


Sweet though! Great results.

 

Great work on getting PID data
Were the observed values while you think the traction control was intervening, or just when in the given setting. (The given value is while spinning wheels, or just sitting in parking lot?).

 

Great job fellas!

 

The values were while the tires were in motion and the traction light was flashing.

It was pritty comical trying to steer with my arms, use both hands to get the screen shot, and make sure I didn’t get too much traction and do something stupid.

 

You guys remind me of me back in Dec. 2009 after I got my new Tacoma... I just had to find out what they added from my 2005 (with none of the traction gizmos beyond the locker on it). H4 TRAC and L4 A-TRAC were both amazing and so much more than the 2005 4WD with just the locker could do.

 

Wow nice. This is good stuff. I interpret this as no engine regulation from TRAC in 4Hi or 4Lo. So the default 4Hi mode in @David K 's Tacoma is still the default 4Hi mode all these years later. They just added an in between mode...TRAC OFF VSC ON which to be honest seems worthless really. I mean in 99% of cases it's the same as TRAC OFF VSC OFF which was available on @David K 's Tacoma with a long push. I suppose why not have it but it doesn't really bring anything to the table except maybe an intermediate hooning mode? Lol. You can hoon as long as you remain stable but if you lose control VSC will save you. Seems like a stretch for Toyota but whatever I guess.

 

Terrific. The standing still Techstream data looks worthless. I considered trying to do another jack test with Techstream data too, but it justs takes so much time. Spouse will probably murder me as it is.
Prioritizing sucks.

 

OP updated with latest additions. @BigWhiteTRD in the latest update I assumed that Crawl Control without MTS resulted in open diffs only because the TRAC OFF light is on. I was always under the impression crawl control was just controlling speed and MTS was controlling traction so that would make sense but someone may want to test this. It could be wrong.

 

Same here... MTS was the new-adjustable A-TRAC and Crawl was 'cruise control' while MTS /A-TRAC-ing!

Toyota is sure making it hard for us to put out an info card on all this!

 

More tests would be suggested to help lock it all down, especially if repeated by someone else besides the original tester. However my previous jacked up wheel tests should apply to this case.

My previous test notes indicate that when I tested Crawl Control, I had only crawl control on (No MTS), as I had the 'TRAC-OFF' light illuminated during CC test. In Crawl Control, my test notes indicated that the truck appeared quite intent on overrun the wheel chocks. (If the truck was running completely open diffs, there should be no tendency to overrun the wheel chocks.) This correlates with my memories, but I would want a double check before saying with absolute certainty.

Maybe TRAC defaults on with CC, and can be upgraded to MTS... don't know for sure right now...

 

Crawl Control is a low range feature and in low range the A-TRAC/MTS is the traction system (on the Off Road TRD 4WD). Have we (you guys) concluded that there is a limited slip in L4 other than MTS/A-TRAC on the Off Road TRD?

 

The more I think about PB’s work and the first video he posted, and all the stories we’ve heard about from different members experiencing Toyota’s new magic, the more I believe us SR/5, sport, and limiteds have ALSD (no engine regulation) in both HI and LO. Those that don’t believe will eventually have to deal with it. It be a dream up front as well, but if it’s TRAC, it has become stronger and more complex. Too many signs, most importantly the front left wheel being stopped completely in mid air. And the work he accomplished today is just too overwhelming. “Numbers don’t lie.”

I’m unfortunately feeling under the weather. Otherwise I’d be taking a drive up to Gorman just to feel that magic again. It can be addicting. It’s hard to describe “the high” having owned an ‘08, ‘12 OR. It’s just a different beast.

Damn proud SR5 4x4 owner.

 

In what situation does one consider locking the rear differential? And why...

 

When you get stuck or can't get up an obstacle with 4Lo A-TRAC/MTS. And then once/if you get out or up the obstacle disengage it. It should be your last resort. With that being said if you are doing extreme crawling where you are lifting a tire constantly you could just leave it on. What you don't want to do is just cruise around with it on when it's not needed.

As for why, the purpose of the locker is to the lock the rear wheels together. So all power that goes back there is split 50/50 between each side.

A-TRAC and MTS are kind of already taking care of this to a degree. They will prevent all power going to a lifted wheel but the locker is there to fall back on in the event A-TRAC/MTS isn't getting the job done for whatever reason. Truth be told though, the number of scenarios where 4Lo A-TRAC/MTS fails to get you up/out and 4Lo Locked does is going to be few and far between. I'm sure they do exist but A-TRAC and MTS are pretty good systems...they do their job well so the locker doesn't bring that much more to the table. It is an excellent fall back to have though...as good as those systems are, you can't beat locked.

 

It is the last resort if A-TRAC/MTS cannot alone get you out of a stuck. When locked, steering control is not the same so to avoid hitting a tree or going off a cliff (because turning takes longer with the locker) Toyota advises only to use to get unstuck and disengage it as soon as possible.

The A-TRAC (MTS) system does not have these restrictions and will most likely give you the same or better traction than the rear locker alone. That has been my experience owning two Tacomas with only the rear locker and one with A-TRAC (and off course the locker).

 

You can't cruise around too far as the locker automatically shuts off at 3mph, right?