No A-Trac

I've got a 2019 TRD Off Road and am still learning about the truck's abilities. I've read David K's traction guides (both of them). Those are excellent resources.

My truck lacks A-TRAC however it does have crawl capability. I have yet to use that other than on a dirt lot when test driving the truck. Is crawl intended to replace A-TRAC?

 

manuals have A-trac.. Automatics have crawl control.

 

Someone please correct me if I'm wrong, but I thought A-Trac was "mixed in" with the MTS options?

 

A-TRAC is "MTS" on the automatics. It's basically A-TRAC with user adjustable slip ratios. A-TRAC and MTS are forms of traction control.

Crawl control is a different control scheme and maintains a set speed. Crawl control is a form of cruise control.

From the factory service manual:

 

^This

 

A-Trac and MTS are synonymous. The only difference is MTS is adjustable for the amount of slip is allows before grabbing the wheel. They work on exactly the same principle.

 

Some no-nonsense MTS info, Canadian style. Toyota Canada has some decent videos on each of the features.

https://m.youtube.com/watch?v=E0y9FVDCF2I

 

OK. Thanks for the help. Last couple of days I spent some time one some really rocky and sandy trails. I think I have this figured out. Just more practice.

 

The MTS feature is super useful. I use it more than Crawl Control or the Locker. It’s subtle, but very effective. It’s good to find a steep loose part of a trail to practice on with the different modes.

 

just mash the skinny pedal and send it

 

So I was out on a steep and loose trail and indeed MTS was straightforward and helpful. And fun. Crawl mad a lot of noise and was real jerky, starting off with a bang! Not sure I see much use for it. The Locker will definitely have a use, someday. BTW, does the on board computer know the wheel(s) are slipping? Some sort of torque-speed curve?

 

ATRAC is kind of like beefed up traction control, whereas crawl control drives the truck for you

 

I’ve never found a situation where I decided to use MTS. If I’m on terrain which I need momentum (sand, snow) then I usually need 4hi and can’t use MTS. Then when I’m going slow and I’m some wombat holes I just flick the locker on. I would like to try it more but I’ve never really ran out of options and need to use MTS. Interested on what you use it for.

Edit: maybe rocky surfaces? Don’t know. I’m not on those very often around where I live.

 

Absolutely it does. The skid control ECU knows and gets input from wheel speed sensors at each wheel. So it knows the individual wheel speeds and depending on the active system (A-TRAC, TRAC, autoLSD, VSC) compares some wheel speeds to certain other wheel speeds and at the defined threshold of slip for the currently active system either brakes wheel/s or cuts engine power or both.

 

I hear ya on this. At first. After remembering I have it I used it in snow and it helped alot. Ended up going pretty good for awhile. It helps keep the truck from cutting power to all 4 wheels when in 4 low and helps maintain momentum by not free spinning then power cut 100% to bury yourself.

 

I like it on snowy hills, where the locker can be a liability by breaking the whole rear end free. It is like a “soft locker”, or something more like limited slip. I have also used it in trenched-out muddy, twisty tracks, where I want all wheels moving forward, but also have to steer and don’t want the locker to push me straight ahead.

Admittedly, I might be engaging the system is scenarios I could get through otherwise, but after testing the system out and comparing, I am convinced it buys you a margin of safety for not breaking the vehicle, or getting stuck.

 

Each wheel has a sensor that detects that it is rotating and at what speed. The truck’s computer knows the engine power output, the transmission gears, and the speed of each wheel relative to every other wheel. It calculates the traction control variable and actions based on this knowledge.