HAC - Hill-start Assist Control

[Maddus Lurker Find all posts View Profile Close Maddus]

Hi Guys

I am new to the forum and this is my first post. I recently purchased the Prado Altitude 2013. According to the spec, this vehicle is equipped with Hill Assist Control (they say all automatic models has this feature).

I tried testing the HAC on a steep slope. I can see that the vehicle is trying to apply break without my intervention to stop from moving backwards. (could hear the breaking noise). However the vehicle was slowly moving backwards.

Is this the way the HAC is suppose to work? I was in High gear when this was tested. Should the vehicle be still, without moving backward at all? Or should the low gear must be engaged to make it work.

Appreciate comments if some one has experience this before..

Sam

[ntp Addicted PP Member Find all posts View Profile Close ntp]

Mate - welcome to the forum.

you might want to re-title your thread to give a better indication of the issue instead of just 'Hac'. That way you'll be more likely to elicit a response.

[smakb Advanced Member Find all posts View Profile Close smakb]

Not all automatics have it. I have a 2010 GXL and it does not. Could you be looking at the Hill Decent Control? That's what I have and that's what it sounds like. Have a closer look at the button.

[Bassett Member Find all posts View Profile Close Bassett]

Maddas, are you talking about how the vehicle (auto model) holds the brake on for a few seconds when on a hill giving you time to take your foot off the brake and onto the accelerator to start moving forward? If so, it holds it for a few seconds only and then releases.
My SX has it and I love it, particularly when towing the caravan.
Regards
Bassett

[talk2tiny Moderated member Find all posts View Profile Close talk2tiny]

My 2012 gal does it. Usually when I stop to go in my gates, my back wheels rest on the lip of the gutter. When I go from brake to accelerator, the car drops back a cm or so and the brakes engage till I take off, presumably to stop me rolling backwards. It sounds like what you're describing. I don't know how long it would hold like that for though as I usually just take off. Mine definitely does hold though as it never let's the back wheels roll all the way back to the road.

[smakb Advanced Member Find all posts View Profile Close smakb]

Time for me to find a hill and see what mine does

[Guest Close Guest]

Info on HAC from Toyota http://www.toyota.com.au/prado/featu...l-start-assist

[kav Avid PP Poster! Find all posts View Profile Close kav]

I have it in my manual Toyota truck , and I hate it and don't use it , I have something like it in the 120 grande and like the downhill assist , it's pretty much useless . Left foot brake , right foot accelerator , works better for me

[ru_altitude Lurker Find all posts View Profile Close ru_altitude]

Hi Sam, I agree with smakb. I have the same rig as you, if your pressing a button it's Hill Descent Control which will let your rig progress slowly down the hill while braking and making noise. The Hill Start Assist just works without pressing any buttons, while on a hill take your foot off the brake, but it will only hold for a short while, long enough to move your foot from the brake to the accelerator and get going without rolling back.

[Maddus Lurker Find all posts View Profile Close Maddus]

Thanks guys for your comments.. like suggested by Ru, I think it may be holding the vehicle only for a short while. The breaking noise is much lower than when you engage Down Hill Assist. However one of my other mate having the same model, told me that his car holds much longer period. He also said that he had L4-engaged when he experienced that. But I have not tested this with low gear.

[Maddus Lurker Find all posts View Profile Close Maddus]

Hac

I think if your's is 150 series automatic, you should have this. It is built in to the system but there is no switch on the dash similar to Down Hill Assist (DAC).

[yowie Advanced Member Find all posts View Profile Close yowie]

The H.A.C. does not prevent your vehicle from rolling backwards on steeper hills, it only works on the small to moderate hills.

Fitted to all 150 autos from what I can determine.

Just try different sized hills until you get an idea of what works and what won't hold the Prado. When you get an idea of what angle won't hold with the H.A.C., a quick grab of the handbrake (hold the button in with your thumb) start to slowly accelerate and drop the handbrake handle down into the 'off' position and away you go. Some hills are just too bloody steep for the system to work.