Wut the hell is "Auto LSD"

2011 TRD OR. 4wd On the way to work this morning, driving down the highway, minding my own business, and a dash light comes on. Says "Auto LSD". First chance, I pull over and shut off the truck and restart it. Light off....doesn't come on again. In my office now, no time to go read manual....

So....What's "Auto LSD"?

 

I guess the better question would be, why would it just come on with no loss of traction, no pushing of any button, etc.....I've read some on why it's there and how it works, but I'm just puzzled as to why it came on for no reason whatsoever. Got me wondering now.....

 

#2more'n likely.....

 

You can also download the owners manual for your vehicle if you like:

http://www.justgivemethedamnmanual.com

 

I had a chuckle when I read this. Eassssy Toyota! It's not a locker

 

When it's functioning, it will (can) cause hard steering though.....The "auto LSD" is a function of the brakes....creating a load on the wheels with the least resistance. I actually know more about it than I let on in the original post. Where I was confused was when it just activated on it's own, on a straight, dry stretch of highway, at a steady speed (around 50mph) with no warning. Still at a total loss as to why.

 

yeah that is a laugh

auto lsd does the same thing a LSD does, it just does it by computer speed sensing and braking one or the other wheel which
forces torque to the other side though the 'ordinary, open differential gears' ...

but steering effect no where close to the steering problems a locked axle has

I turn on auto-lsd in snowy conditions around town when it is half-pavement half-snow
but never have i noticed steering change, I just notice
more forward movement and less slipping of the wheel currently in the snow


------------
activating by itself ? maybe pull the dash switch and check it for cooties ?

 

I'm going to approach this as the anomaly that it is/was. Unless it does it a second time, I'll just write it off as "unexplained phenomenon" and let it go at that. It's just that at 4:30AM, anything out of the ordinary can cause great confusion!

On dry pavement, it did cause a "heavy steering" sensation when I turned off the highway into a gas station lot. Not like a locker, or even like positrac, but you could tell SOMETHING was resisting the rear wheels turning at a different speed.....

 

I understand the principle, I just never found it to be sooo effective to the point it affects the steering. Unless you crank the steering wheel to max travel and drive in circles continuously. Don't get me wrong, it's works eventually but usually takes some time to activate and by then your typical turn is over. Maybe I need new rear brakes

As for your issue. If it doesn't happen again, the switch most likely got hit inadvertently. That's best case scenario, otherwises you might be looking at a 4x4 computer or wiring issue. Have you done any mods or installed switches in the blanks near the " " button

 

No wiring mods....No work in the area of the switch.....and nothing moving in/around the area of the switch....

As I said, there wasn't a dragging of a tire, or anything that severe, but I could tell it didn't turn as easily as "normal"....Apparently the brakes were doing what they were supposed to be doing....

The dash light came on, I travelled about 200 yards before I turned into a gas station to see what was up. By then, I could feel the brake(s) dragging. As soon as I shut of the truck and re-started it, we were back to normal.

The ol' "element of surprise" thingy.....@ 4:30AM.

 

Accidental press of the VSC off switch. No big deal.

 

Failing/failed wheel sensor?

So it 'thinks' it's slipping, but not?

 

At the time, one hand on the wheel, other on my caffeine free diet Pepsi (My version of morning coffee) left foot on the floor, right foot on the gas pedal.....Only one other "extremity" unaccounted for, but I think it was locked up for safe keeping at that moment...

 

That thought had crossed my mind......I guess the way to handle this is to just wait and see if it happens again....

 

Interesting. At that hour I probably wouldn't of even noticed anything haha. Keep an eye on it I guess. Not sure if these things are similar but my 4runner threw on the abs/trac lights and had a code stored in the computer when I broke an ABS wire which is essentially the same thing as a failed sensor. Maybe keep an eye out for that but I'm sure your truck was just tired haha

 

An ignorant question but how would I be able to find out if our Tacoma has LSD? We bought it used a few years ago and I don't recall if they told me or not. It's not in our paperwork and the owners manual includes information for those with LSD and those without. We have a 2008 4x4 TRD Sport. Is there a distinguishing feature on the differential itself that I could see that would tell me? Thanks.

 

Sounds like the VSC needs to be recalibrated... check this link
https://www.tacomaworld.com/search/2296299/?q=recalibration+after+a+lift&t=post&o=date

 

So, you've heard of Pez dispensers right?


The "Auto LSD" is simply Toyota's way of dispensing acid.

You must have the California Edition Tacoma. I hear the Auto LSD comes standard on that version.

 

Auto lsd should only turn on by turning it on. By default your truck is in normal vsc mode. Also, if you felt your turning being affected, that sounds like vsc giving you trouble, not the auto lsd. VSC can make the truck handle dangerously if it turns on when it shouldnt be on.

 

I have a 2018 Toyota sr5 with 4x2 and it rain really heavy today. I went for a drive and the auto lsd turn on automatically with trac off and pre collision off as well. Any explanation? Also I did went on the high way with it on without knowing what it is. I also looked how to turn it off.