DAC does nothing

OK.....I have a pretty steep driveway and we got a little snow. Came home tnight and it was freezing out, so I thought a good time to test the downhill assist. Stopped the truck at the top of the driveway. Put it in neutral, turned front wheel drive control to 4L per manual. Pushed the DAC swith & the DAC icon displayed. Put the gear 2L, let off the brake and proceeded down. Well...I got no braking or slowing whatsoever.
Hit the brakes to slow & stop & tried again......same result, no assist at all.
What am I doing wrong? This in in a 2013 with AT

 

If I'm not mistaken, DAC only downshifts for engine breaking so if Ur truck never got out of 1st it would do anything . I thinks its for big hills on the road when Ur going 40+ ish and wanna save Ur breaks, but I could be wrong.

 

DAC will show it's skills when you are pointed down a steep with rocks you are crawling over, and you happen to slip off the face of the rocks which tends to shove the vehicle forward...stuff like that. It needs to be a little nasty for DAC to show it's kung-fu

do NOT touch the brakes, this immediately turns off DAC


http://www.youtube.com/watch?v=6yxCjP8pYo4


it is meant for coasting down crap you would normally have your brake on
most of the way to keep from bouncing over too much rock or bumps...DAC
can handle it

 

Great link.....I learned something new today!!! I've never used it in my Taco but my wife has it in her Highlander and I never knew hitting the brakes would cancel it out....I have told her to use it for snowy conditions going down steep hills...guess I gave her bad info. haha

 

I guess the 15 MPH is what got me.....I had read elsewhere it goes down hill between 3-5 MPH. My driveaway is gravel (mud), steep and rutted, so I thought it would be an ideal use for DAC.

 

In the condition you describe OP , would 4L , and L gear not keep your speed low enough to not need brakes ?

That must be a really steep driveway

 

This...

I know when I'm in 4L locked into first I am going maybe 2mph tops and thats down steep shit

 

I have used DAC a few times but I looked it up in the owners manual so that you get good info.

1. Must be in L4.
2. Operates at speeds of 15mph or less.

I have always used going down super steep hills and it maintained 2-3 mph. I wonder if you were traveling lets say 14 mph when activated what speed it would maintain? Have fun.

 

OP , is there any chance your 4L had not actually engaged ?

 

The icons showed that 4L was engaged.
Yes, the driveway is pretty steep. Takes me a while to find someone willing to go down it if I want gravel or dirt delivered. UPS and FedEx only come down in the summer, and some 2 wheel drive pickups have trouble going up in the summer. Had to pull a guy up in his Mercedes one time.

Anyway.......as I mentioned, I thought it would be a good testing of the DAC. The hill doesn't bother me, but the wife won't drive down if there is any snow or ice. She still can't get away from pushing that brake when she starts to slide. Was hoping the DAC would get her down so she could stop parking at the top.

 

Honestly sounds like the wrong application for DAC anyway. As mentioned earlier the DAC tends to work well when there is a sudden change in forward motion (like a wheel dropping into a large rut or slipping off a rock). 4L in 1st gear should keep your speed WELL under 15 mph.

 

Did you try the DAC switch as you were moving with your foot off the brake pedal? I've never had an issue hitting the switch during a slow crawl (4L and L gear.) Also, your rear diff wasn't locked was it?

 

DAC assists the deceleration of the engine brake when decending down a steep hill in L4 offroading instead of having to use the brake pedal.

 

Nope.. DAC won't work with the locker engaged. That's why i asked.

 

Paging David K..

 

I still have a hard time imagining how steep this hill is that 4LO , L wouldn't keep your speed in check without brakes

 

In the OP it says snow , not ice

but I agree , if it is a sheet of ice nothing is going to help except sand and de icer

 

If DAC works as in the Land Cruiser video above, I would think it should work on my driveway. My driveway is pretty close in some spots to that shown in the video.
Also..rear diff was not locked. I think I did have the brake on when I pushed the switch, then let off. Do I need to push the switch without any pressure on the brake? Didn't think so as the manual says press the switch and with vehicle traveling at less the 15 mph, release foot from brake or accelerator to activate the system.

As far as the icon showing and knowing I was in 4L....I've only driven the truck for a few days so as yet I can't tell much by feel.

The driveway is mostly mud now, so I'll give it another shot and see what happens. I have a back road out of my place that is much steeper and narrower, but not ready to scratch up the truck just yet.

As mentioned before 4L is fine for me getting down, but the wife is paranoid.

 

Hello Amigos!

I am not going to be techno at all with this one... but it is kind of tied in with A-TRAC in that it uses the same sensors and brakes on each wheel and the idea is to keep you pointed downhill when going down STEEP, rocky grades... I don't know if it is valuable in snow or ice... but you wouldn't use it unless it is an extreme STEEP down grade... off road.

It is different than just going into low range and first gear and using the engine compression and low gears to crawl you down... you still could get sideways and roll.

The DAC will move you at about 3 mph... about walking speed or a bit more and you don't touch the pedals... specially the brake. There are weird sci-fi noises like clicking and springing sounds as it lets the truck drive down the STEEP grade.

It does sense when a big rock pops out from under a tire and keeps you safe. It was kind of nervous to use it the first time... but it is fun... and just another Toyota World of Wonder product we don't pay extra for on the Off Road 4WD Tacoma!

 

DAC is not really for super slick hills. It needs at least one wheel at the moment to have good traction to use for reference. Expectations, are the problem.