HAC - How does/should it work?

[westwind77]

I was curious how HAC does/should work? I read the manual them tested it out a little bit but wanted to know if it is working properly. Drove up a paved incline, stoped half way up, released the brake, truck started to roll back, TRAC light light up, 'dinged' a couple times, truck stoped itself for a few seconds, then you could hear feel the abs pulsating and the truck started to roll back again. How long should the HAC hold the truck from rolling backwards? Is it just enough time to go from the brake to the gas or should it hold it as long as it needs to?

Thanks!

 

[adoihcj]

I was curious how HAC does/should work? I read the manual them tested it out a little bit but wanted to know if it is working properly. Drove up a paved incline, stoped half way up, released the brake, truck started to roll back, TRAC light light up, 'dinged' a couple times, truck stoped itself for a few seconds, then you could hear feel the abs pulsating and the truck started to roll back again. How long should the HAC hold the truck from rolling backwards? Is it just enough time to go from the brake to the gas or should it hold it as long as it needs to?

Thanks!

I think it holds you indefinitely - unless you touch the brakes or press the accelerator. Then it resets itself. I'm not a pro yet, but I think that's how it's supposed to work. The vehicle has to roll back first to let the system know that it's moving in reverse. Once it rolls back, the brakes engage. If you touch the brake again or press the accelerator, the system resets and needs to roll back to be activated again.

I always thought this was good to use so you wouldn’t roll back into someone behind you on a steep road, but I believe it's more for off-roading or slippery conditions so you do not slide backwards uncontrollably.

 

[SSt4r]

Not sure if it's the same but the 4th ge. holds for about 3 sec. I think.

 

[nighthawk]

Not sure if it's the same as the 4Runner's or not, but on my Rav4, after a complete stop, you have to press down on the brake pedal further until you hear a beep. Then when it's time to move again, you release your brake and you have 3 seconds to step on the gas before it turns off. When it turns off, it'll beep at you to warn you first.

 

[westwind77]

Not sure if it's the same but the 4th ge. holds for about 3 sec. I think.

Yes, that is about all it seems to hold for. Just wanted to make sure everything was working as it should.

 

[adoihcj]

Not sure if it's the same as the 4Runner's or not, but on my Rav4, after a complete stop, you have to press down on the brake pedal further until you hear a beep. Then when it's time to move again, you release your brake and you have 3 seconds to step on the gas before it turns off. When it turns off, it'll beep at you to warn you first.

Wow, I was way off. I haven't really tried it yet, so this is very helpful.

 

[buenhec]

I was curious how HAC does/should work? I read the manual them tested it out a little bit but wanted to know if it is working properly. Drove up a paved incline, stoped half way up, released the brake, truck started to roll back, TRAC light light up, 'dinged' a couple times, truck stoped itself for a few seconds, then you could hear feel the abs pulsating and the truck started to roll back again. How long should the HAC hold the truck from rolling backwards? Is it just enough time to go from the brake to the gas or should it hold it as long as it needs to?

Thanks!

Mine has gone off twice just driving up my driveway, its a little bit inclined but just an ordinary driveway. My vehicle rolled back a couple of seconds and the light went off and I heard all this clicking and buzzing in the drivetrain. I dont really know what happened and if it works. I will try out when I have a little more time.