A-TRAC/TRAC/AUTO LSD Explained (Easy to understand, I hope!)

Atrac got me out of 99% of any issues in my FJ. I very rarely used the rear locker. I miss that thing daily.

 

There's a reason to get the Off Road TRD 4x4.
Are you sure the Yellow Wire Mod doesn't work in your truck for 4LoTrac?

 

I haven't seen any mention of it. I figured it was just for the 2nd gens.

 

Still playing with the 4H modes. I'm not all that impressed with the normal 4H in the snow (4L with ATRAC seems to get out of just about anything at all) - perhaps im not used to it quite yet. Im getting a lot of flare up with ABS which i understand is expected with traction control. I still have some playing around to do with the TRAC Off and VSC off - would you fellas recommend normal 4H with trac and vsc engaged for more snow applications when driving normally? It's been icy here too which doesn't help the tire slip/spin.

 

TRAC OFF (which is Traction Control with the engine regulation turned off) for the win. Don't be afraid to put your foot into it.
The same is true with A-TRAC in L4, which does have engine regulation (to prevent tire spin). If the truck just stops moving but you want it to move: heavy pedal! I have "woke-up" A-TRAC on a steep climb when it wanted to stop climbing by mashing down on the gas pedal. It worked!

 

Another question for you David. I have a 2009 TRD Sport 4x4. I have a switch for Trac but no switch for VSR. In 2wd when I push the Trac off the following shows on my instrument panel - Auto LSD is shown in red, it doesn’t say on or off just Auto LSD. Also shown on the instrument panel in yellow is the Trac off symbol and the word off below it. So does this mean limited slip is on or off? Is track off. Or partially off?
In 4H I have to hold the Trac off switch down for a couple seconds and then the Trac off symbol appears with the word off below it but no Auto LSD lights up as it does in 2wd. I thought I understood all this but now I’m confused. Any enlightenment you can give is appreciated. Thanks

 

The button (switch) with the car and squiggly lines under it is called the VSC OFF SWITCH (not a TRAC OFF switch) The one button controls both VSC (Vehicle Stability Control) and TRAC (Traction Control).

In 2WD and 4WD-HI, your truck and mine (2010) are the same. Only in L4 is there a difference between an Off Road TRD and all other Tacomas.

The Terms (2009-2011*):
TRAC is Traction Control (Limited Slip System). Helps you move ahead when one tire begins to spin.
AUTO LSD is 2WD Traction Control without the engine regulation (throttle cut). It is also called TRAC OFF by Toyota (this is TRAC with the regulation turned OFF).
VSC is Vehicle Stability Control which helps you keep going in the direction you intend when the vehicle begins to slide sideways.
VSC OFF is to deactivate BOTH TRAC and VSC. It will turn itself back on if the vehicle's movement becomes dangerous; and/or every time you restart the truck; and/or you re-press the button.

*In 2012, Toyota added a selectable TRAC OFF mode to 4WD-HI, requiring a quick button push in H4.

2009-2011 in H4 was normally in the "TRAC OFF mode," without a button push. It was called TRAC, not TRAC OFF in those years. There was no light then. 4WD-HI (2009-2011) is always without the engine output regulation. This was confusing to some who did not read the tech literature of the time. Adding a regulated TRAC to the non-regulated TRAC OFF (in 2012) maybe was to clear up this contradiction as well as give a 4WD "Lite" mode if one did not always need the regulation turned off?

The operating actions:
In H2, a quick press of the VSC Off button engages AUTO LSD (same as TRAC OFF) which is enhanced TRAC (as there is no engine regulation). The VSC is also off, but only to 30 mph when it comes on automatically.

In H4, you need not push any button (2009-2011) for enhanced traction control. It was automatically in the enhanced (no engine regulation) mode.

In H2 or H4, if you stop moving, then press and hold down the button for a few seconds (until the VSC OFF light comes on), you diserengage both the VSC and TRAC systems so your tire(s) can spin freely.

Press the button again or restarting the truck will return you to normal TRAC mode.

 

I Truly appreciate your time and effort here David. You have enlightened me so now I feel I understand this whole thing. I’m going to print this explanation and frame i5 in my man cave. Thank you again. If you are ever out in N California let me know, I’ll buy the beer.

 

That is way cool of you amigo!
I would really like to party with all of you... especially out on the trail, in 4WD!
If any of you get the motivation high enough to go camping in Baja, I am happy to help with that, too! See my 7 detailed trip reports in 2017, posted on the TW TRIP REPORTS FORUM: https://www.tacomaworld.com/forums/trip-reports.180/ (its kind of hidden in the Off Roading & Trails forum).

Here's a short preview of an all Toyota 4WD tour I led in 2016. Enjoy the tunes!:
https://www.youtube.com/watch?v=kAWGzW4bR9Q

 

I'm so lost on this whole thing. I got a limited so I don't think I have a rear locker. Can someone just tell me what is and isn't engaged when
1. You start your truck and drive normal
2. You press the button on the overhead furthest left I believe it's the vehicle stability button
3. Yiu press and gold that button

 

What's the last piece of the puzzle? The 2011-2015 years or were there more changes & variations?

 

1 is light traction control
2 is traction control without engine regulation, Trac off
3 is traction control and engine regulation off

The only 3rd gens with lockers are the pro and offroad

 

So what's the diff between 2 and 3?

 

2 is strong traction control without engine regulation
3 is no traction control at all... ie, traction control and engine regulation are off.

 

By George, I think he's got it!

 

So 2 has better traction but 3 has more power?
I don't get what you mean by engine regulation

 

3 allows wheel spin to clear mud or snow... Or to do donuts and drift.

 

Right and the 2 cuts the power to the wheel that's slipping?

 

Yep via the brakes

 

What