Greetings:

In order to test the DAC function wiht my 04 4Runner Sport Ed, I perform the following steps:

1. Vehicle is completely stop at traffic light with shift lever in D position.
2. Turn clockwise the H2, H4, L4 knob all the way to L4 position.
3. The 4x4, LO4 indicator lights up with a continuous sound in the cabin.
4.Push the DAC switch and start driving downhill on a 30~40% slope about 1 miles long.
5. The DAC indicator is blinking, the SUV get momentum and keep accelerating downhill, I have to pump the brake intermetently to keep the speed below 35mph.

Do I perform this correctly? If so, what is the DAC suppose to do?

Your input is greatly appreciated.

 

Here is what you did wrong
Step 1., step 3, step 4, step5

4lo, DAC and traffic light should NEVER be in the same sentence.
DAC and 4lo are off roading features. Carefully read your manual on the operation.

The 4lo was beeping because it was not engaged.
When you are in 4lo, you cannot go 35mph as described and when DAC kicks in, you will know it baby!

DAC is to keep control while descending steep terrain OFF ROAD. Not on road.

When do you use DAC? If it looks like this:

 

There's an instruction card in a plastic holder on your sun visor. Follow the instructions to put your vehicle in 4Lo, then point the nose downhill and operate the DAC switch.

 

If you use DAC, you'll be going about 1mph. I've used it a few times but it really gets in the way :/

Anyway... To use this feature: When in 4x4, make sure you're always on NON-pavement surface!!

Get into 4lo (best way is to be parked i.e. "P". but if not, neutral is okay too)
The light on the dash should become solid when you get into 4lo.. Also you'll hear the gear engage (sounds interesting).

Then click on the DAC. It'll blink for a few sec and then go solid. Once it is solid you're using it. And you'll figure quickly how SLOW you'll be going... O yeah, you should already have your center locked btw.

Anyway have fun Beware for the beeping like crazy stuff btw, as it gets real annoying real quick!

Enjoy

 

Also, do not touch throttle or brake any time DAC is engaged, just steer. If you do touch the brakes, the sudden decel could upset the truck on a slippery surface, then when you release the brakes again the electrohydraulic brake pump will need to work overtime to regain control. Note that extended use of DAC will overheat the pump and cause an overtemp alarm, a condition I encountered during an unusually long, steep descent, about a mile and ~15% grade. It recovered quickly, well less than a minute.

 

Thank you all for your input and help.

Why "non pavement" is a factor to operate DAC? I read though the manual and didn't see it mention anywhere. Anyway, how do you test your DAC then? Do you have to go off-road to test this feature? Where I live, I have a few steep hill about 30 to 45 degree on pavement road but no off-road area.

 

The reason for the "non pavement" factor is because to use DAC, it has to be in 4lo. You never ever want to be driving in 4lo on the pavement as you'll damage ur 4wd system.

This DAC is a offroad feature so if you want to test it out, make sure you're not on any pavement surfaces.

 

Point of order: That's only true for the V-6 driveline system when turning. It's fine to use 4Lo on-pavement with the V-8, and to test DAC there. What you absolutely want to avoid is locking the center diff at any time on-pavement, in either 4Hi or 4Lo, with either system.