My driveway is on an incline and while sitting still on the hill I let my foot off the brake to see if the 4 runner would stay in place. It started to drift backwards and make a jerking noise and motion like it was trying to stay in place. Is this normal? I thought it was supposed to keep from going backwards. By the way I did have it in drive.
While stopped on a hill.
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KCcarguy
New member
So this is the HSAC? I'm glad the OP brought this up. I was confused about this myself because my HSAC works much smoother on my wife's Highlander. On the highlander you just depress the pedal firmly, a tone sounds, and the car stays in place. I wonder why it's different in the 4runner?
1engineer
Moderator
What hapens if you coast to a stop going up a hill and start drifting back without hitting the brakes on your wife's Highlander?
westwind77
New member
It is called HAC to start with 
Secondly, if I remember right from reading the manual (gasp)...you are suppose to, while on the incline, firmly press down on the brake, then release.
I noticed if I came to a stop on an incline and stopped normally, light brake pressure, then released, the 4R would roll back a bit before activating.
However, if I stopped on an incline and firmly pressed the brake down, almost to the floor, then released, the 4R would not roll back (same incline).
2010 Toyota 4Runner: Hill Start Assist Control (HAC) - YouTube
Secondly, if I remember right from reading the manual (gasp)...you are suppose to, while on the incline, firmly press down on the brake, then release.I noticed if I came to a stop on an incline and stopped normally, light brake pressure, then released, the 4R would roll back a bit before activating.
However, if I stopped on an incline and firmly pressed the brake down, almost to the floor, then released, the 4R would not roll back (same incline).
2010 Toyota 4Runner: Hill Start Assist Control (HAC) - YouTube
1engineer
Moderator
It is called HAC to start with
I noticed if I came to a stop on an incline and stopped normally, light brake pressure, then released, the 4R would roll back a bit before activating.
However, if I stopped on an incline and firmly pressed the brake down, almost to the floor, then released, the 4R would not roll back (same incline).
2010 Toyota 4Runner: Hill Start Assist Control (HAC) - YouTube
There are times offroad when you start to roll back before you "depress the brake firmly" as the manual says. I assumed by the noise the OP described he did as many of us do and started rolling before braking. Hence "two foot" operation for steep stuff.
rickwol
New member
I'm glad I saw this post and so I tested mine just now as I too have a steep inclined driveway. If I roll up to the top without touching the brake, the vehicle will roll all the way down the drive albeit slowly making the typical noises everyone hears including "beeps". If I roll up to the top and step on the brake lightly it will stop and then start rolling back. Each time I hit the brake while rolling it stops and then starts rolling back on its own with increasing speed. The vehicle then "stalls" at the bottom of the driveway. I tried this twice and each time it did the same with the stall. I've never had this vehicle stall on me. Hmm, I'm not sure if this is by design or not but it doesn't seem quite right. I would next like to try stepping on the brake hard to see if it behaves differently.
1engineer
Moderator
Firm.
KCcarguy
New member
Not sure. I'll try tomorrow.
That's how it works on the highlander, but not my 4runner. Maybe I'm not pressing firm enough. So....just to clarify:
-Does the 4runner not make a tone to signal HAC is acitvated?
-Once the HAC is activated, you can take you feet off both pedals and the truck will not roll back at all?
-You don't have to be in 4WD for it to work, right?
DKuhen
New member
I just tested this earlier in mine. I came to a stop with the brake on a hill. I let off the brake and did nothing else. It rolled back a few inches and stopped. After a few seconds it started rolling back again. Once I started rolling back again I hit the brake. I didn't test it further.
AustinCyclist
New member
2011 Toyota Sienna: Hill Assist Control - YouTube on this sienna, it beeps, does the 4r beep too?
4r vid: http://www.youtube.com/watch?v=dyIv8j-uE_E
4r vid: http://www.youtube.com/watch?v=dyIv8j-uE_E
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DKuhen
New member
I'll try to use it like in that video. I'll take a video of my own and post it in here.
DKuhen
New member
Here's the video. Pushing normally on the brake or pushing firmly on the brake did not seem to change the way it worked at all.
HAC - YouTube
KCcarguy
New member
Great vid! This is very different than the Highlander.
4Run4YourLife
New member
Thanks for the video. HAC doesn't seem as useful as I expected. I was really looking forward to it on the boat ramp this summer. Bummer.
westwind77
New member
How steep was the hill you were trying to activate it on? Curious if it responds differently on a steeper grade.
You said 'it only stops it for a couple of seconds', to me that is kinda the whole point of HAC. It is suppose to keep the vehicle motionless (or close to) for the time it take you to get your foot from the brake to the gas. It is NOT designed for you to take your foot off, get a burger, then come back to the 4R on the spot on the hill.
If you can release the brake and press the gas on an incline without the 4R rolling back sharply then the HAC has done its job I think.
1engineer
Moderator
If I were designing it I would work under the design parameters of only needing to hold vehicle in place for time needed to shift foot from brake to gas. Maybe a few seconds. Then again I don't work for Toyota though. If I have time I will test this function more thoroughly. As I said, I just two foot it but I am old school.
kmiller8821
New member
:iagree: Love the part about get a burger. lol
