3rd Gen Traction Control Modes Explained

nice write up

 

@H3llRid3r, check out page 1. Seems like we were recently talking ourselves into a black hole trying to figure this shit out.

 

Ha, yes I’ve been reading this thread.

 

The black hole of traction control! LOL

 

I'll do what I can where I'm at (it's pretty flat here in Houston). Also, getting the time to drive around and find a (legal) place to test is tough.

Why couldn't Toyota clearly explain the modes!? All this should not be such a mystery.

 

COMPLETELY CONTRADICTORY!

TRAC helps to "maintain DRIVE POWER".

TRAC/VSC "may reduce power from the engine"

OK, fine, so let's ONLY turn off VSC. Except you can't. One press of the truck/squiggly/off button illuminates TRAC OFF (which means TRAC "cannot be operated"). A long push of the button does turn off VSC, but TRAC OFF is still illuminated. There is no singular VSC OFF mode.

THE ONLY guess/hope I have is that in 4H, VSC's programming is less aggressive with power reduction. Otherwise, in 4H (in sand, for example) you'll either be constantly cutting power, or you'll be spinning away with open diffs.

It looks like 4L is the only way to have LSD/locker-ish performance on BOTH axles. BOO.

 

PRE-K, I think in playing with each drive mode, you may find things are not as they are described in the book! The book does not even come close to acting as a guide.

Just get outdoors, find a soft area (sand, for example) and a steep hillside... deep ruts are great, too.
Put the truck in each of the 10 or whatever drive modes and see how it gets through or over in each mode.

My biggest question for the newer Tacomas is wondering if the terms became reversed. For us Second Gen Tacomas, Trac Off meant the engine regulation was OFF for a stronger Traction Control. In H2, Auto LSD and Trac Off are the same (per Toyota). In H4, Trac (until 2012) had no regulation, then in 2012 a Trac Off button push was added and Trac in H4 then had regulation (like Trac in H2).
So for Third Gens:
1) Trac vs. Trac Off in H4, which is more traction or which has engine regulation?
2) Is there really any traction control in L4 (other than the locker and A-TRAC/MTS/Crawl)? Is it under Trac or Trac Off settings?

 

DavidK... thank you for the reply... I hope you're right!

The book says (for whatever that's worth, not much apparently) that selecting 4L turns off everything, including TRAC, VSC, ABS, etc., and the only traction control settings in 4L are MTS, CC, and the locker.

I hate that I haven't had time to test my truck yet. I've had it a month, but life has been hectic! Soon... I hope! I'm still miffed / baffled that Toyota can't / won't effectively explain their product's features!

 

I was able to use “TRAC” in my 2017 SR 4x4 automatic over the last weekend. I took my daughter up to Kennedy Meadows and found the gates open to Monache Meadows. The rangers said trail wasn’t officially open yet but some Geologist had left the gates open. Inyo County rangers waved at us as we drove in .

There are only two mildly technical sections of trail. Both are uphills about 200 ft long with 1 foot diameter boulders, ruts, and tree roots.

I was towing my off road trailer, 2000 pounds, and left the tires at 50 psi.

The truck was in 4low. VSC OFF was lit up on dash. Vacuum booster truck.

I left the rear arb open.

During the climb up I lifted the front left tire into the air over a foot followed be the right rear into the air.

The truck flashed the squiggly traction light as soon as the tire went into the air and my truck climbed forward with no problems. I was impressed with the most basic form of Toyota’s traction control “TRAC”.

This was all a test. Normally I would have been at 10 to 15 psi and would have locked the rear, and crawled slowly up the hill.

 

Thank you for posting PB FAB... interesting what you discovered... selecting 4L is supposed to automatically turn off TRAC, but apparently it doesn't (no "TRAC OFF" light illuminated).

I guess David K is correct... the manual is only a suggestion as to how the truck might operate. The translation to English can't be THAT bad, can it?

 

I think it was indicating A-TRAC, not TRAC.

 

The really sad part is that most just don't care to know...

I wanted to know everything about these traction systems so I can get the most performance from my truck.

And, I have from my 2010 and it has been the best of my three Tacomas because of TRAC and A-TRAC.

I just would think more Third Gen Off Road 4WD Tacoma owners would want to know what is each mode of traction control doing so they can get the most benefit from their $34,000+ investment.

I am just curious about what has changed since my model.
There have been a couple of you who did a lot of work on this but it sure seems opposite of what I have found as far as TRAC in H4 vs. TRAC OFF and TRAC or TRAC OFF in L4.

Remember, at least for 2nd Gen, 'TRAC OFF' is NOT TRAC turned off, it is more TRAC with the engine regulation turned off.

This is the same as AUTO LSD in H2 (also a TRAC OFF mode in the 2nd Gens). They should have just used the same stupid name (Auto LSD) in H4, or got rid of the name in H2 and just use TRAC OFF for both.

VSC OFF is the mode that is also TRAC turned off... at least in the 2nd Gens!
LOL

 

A-TRAC is only on Off Road TRD 4x4s.

 

Base model SR - no A-TRAC.

 

Right...because it requires the hydraulic brake booster...or does it?
My thought is, it just requires 4-channel ABS. A-TRAC would just be more effective with it's[hydraulic] increased braking power.

Not to rely too heavily on the FSM, but it does indicate 'A-TRAC control active' as one indicator of the slip indicator light blinking; for vacuum boosted 4wd.

What about FJs and 4Rs with A-TRAC; all hydraulic boost?

I wish we could pick Nishimura's brain...

 

The results observed by @PB FAB matches what we had previously found precisely and is represented in the spreadsheets. In fact I believe the PB FAB actually contributed to the data we have. On the SR, in 4Lo the default behavior (no button presses) is:
TRAC ON, VSC OFF
(you wont see any lights for the TRAC ON on the dash, until the system decides to react).
You get the VSC OFF to indicate that stability control is off. Stability Control is separate from the Traction Control

When TRAC operates you get the squiggly.
The VSC OFF light is 'squiggly' with an 'OFF'



Note, TRAC operates with the standard vacuum brake booster.

 

There are (2) options for the SR/SR5/Sport/Limited in 4Lo.
TRAC ON, VSC OFF (Default)
TRAC OFF, VSC OFF (Long Press VSC Button)

Here are the Dash indications you get for the two modes.
Notice, when the TRAC OFF light is On, then there is NO traction control.

 

Correct, only the hydraulic brake booster can fully stop the spin to match rotation with the traction tire on each axle.

 

OK, finally finished reading this thread. Great info.

However, I still haven’t figured out what the difference is between MTS and CRAWL. With MTS I can select the terrain and with CRAWL I can select the speed. Any other differences?

Also, if both these modes simulate a locker, is there really a need to have either mode selected with the locker engaged?

So far, I’ve only used 4LO and the locker and have been able to do anything I’ve wanted to.

The one time I wanted to try the different modes I had damaged the drivers side ABS sensor and all hell broke loose. Had a hell of time getting the rear locker to engage. All others systems were kaput.