Does SR5 has hill start assistant control?

[quhongjun]

Just bought a 4T SR5, but I didn't find the HAC as toyota claimed?

Yesterday when I was stopping on a steep road, I didn't realize that the brake was not held tightly enough, and the 2010 4Runner was slowly rolling back! The car behind horned at me before I hit him. I think if my 4runner is quipped with HAC, this kind of thing won't happen. Right?

Now each time when I start on slope, I will have to apply the left-foot brake first before I move the right foot for gas pedal. It's really unhappy.

 

[jpowers]

Not sure on the SR5, but on my limited it takes a few seconds for it to kick in. There is no switch that I could find to turn it on. I'd say the truck rolled back about 5 feet before the breaks kicked in.

 

[kingpin748]

5 feet seems excessive. I would have thought it would kick in almost immediate.

I could do a manual in better than 5 feet....

 

[7harper]

Just bought a 4T SR5, but I didn't find the HAC as toyota claimed?

Yesterday when I was stopping on a steep road, I didn't realize that the brake was not held tightly enough, and the 2010 4Runner was slowly rolling back! The car behind horned at me before I hit him. I think if my 4runner is quipped with HAC, this kind of thing won't happen. Right?

Now each time when I start on slope, I will have to apply the left-foot brake first before I move the right foot for gas pedal. It's really unhappy.

Not sure what "I didn't realize that the brake was not held tightly enough" means. Either you have your foot on the brake or not.You still have to have your foot on the brake pedal on a hill. HAC helps from rolling back in the brief period it takes to go from brake to gas pedal. It's not a substitute for the brake pedal.

Here is a good explanation Avoiding Accidents

And Toyota's video....
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If yours does not work like this ,then take it back to your Toyota's service dept and have them check it.

 

[MaylonTRD]

Not sure what "I didn't realize that the brake was not held tightly enough" means. Either you have your foot on the brake or not.You still have to have your foot on the brake pedal on a hill. HAC helps from rolling back in the brief period it takes to go from brake to gas pedal. It's not a substitute for the brake pedal.

Here is a good explanation Avoiding Accidents

And Toyota's video....
<object width="640" height="385"><param name="movie" value="http://www.youtube.com/v/kiFVKNSAeJ4&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/kiFVKNSAeJ4&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="640" height="385"></embed></object>

If yours does not work like this ,then take it back to your Toyota's service dept and have them check it.

I think that about as good an explaination you could give!

 

[jca21]

i dont know about HAC.

maybe just paying attention and some driving technique could solve the problem?

you could always give left foot braking a go if you're on a really steep incline and the guy behind you is right on your ass. or you could always give heel-toe a go.

 

[quhongjun]

Not sure what "I didn't realize that the brake was not held tightly enough" means. Either you have your foot on the brake or not.You still have to have your foot on the brake pedal on a hill. HAC helps from rolling back in the brief period it takes to go from brake to gas pedal. It's not a substitute for the brake pedal.

Thanks for your explanation, MaylonTRD.

What I mean is, my foot was on the brake pedal, but the pedal was not fulled pressed, so it can still roll back slowly.

From the video you posted, I can't see the driver's foot operation. But from the car movement, it's different with mine. My car will always roll back at least 1 foot before it continues to go up. That's why I'm wandering if my 4T SR5 has HAC installed.

 

[Titanpat57]

There is one particular hill I drive on almost daily. At the stop sign I just remove the brake, it rolls back maybe a foot or less, and starts clicking, then beeps, meaning you have 3 seconds before the brake lets go and you will roll backward..buy that time you've hit the gas, almost spun the wheels...and now the damn traction control is beeping!!!

lol..driving in the 21st century....who'da thunk it?! :bigok:

 

[adoihcj]

Thanks for your explanation, MaylonTRD.

What I mean is, my foot was on the brake pedal, but the pedal was not fulled pressed, so it can still roll back slowly.

From the video you posted, I can't see the driver's foot operation. But from the car movement, it's different with mine. My car will always roll back at least 1 foot before it continues to go up. That's why I'm wandering if my 4T SR5 has HAC installed.

All 4WD 4R's have HAC.

From my understanding of how it works, the vehicle has to move backward a little before it recognizes that it's moving backward. Then the HAC kicks in. It only holds for a few seconds, so you will need either apply the brakes or give it gas to stop it from rolling backward again.

When I first bought the 4R, I thought HAC was meant to keep you from rolling backward on steep hills on public roads. However, I've come to learn that it's really meant as an assist for off-road driving.

 

[RHINOSAUR]

All 4WD 4R's have HAC.

From my understanding of how it works, the vehicle has to move backward a little before it recognizes that it's moving backward. Then the HAC kicks in.

does it simply measure backward roll of the wheel some how? or does it actually use an accelerometer to measure the vehicle's orientation with respect to gravity??

I would have though that the 4runner has a little mems chip, kind of like the one found in the i-phone or i-touch that measures orientation with respect to gravity (vertical) so that it knows ahead of time that it is about to roll backwards.
Also, this would be a particularly useful sensor to determine the brake settings on the more complex brake modulations used for the crawl control and downhill assist found in the trail and limited.
so basically the SR5 has the same sensors found on the limited and and trail but its just that the SR5 does not have all the suspension hardware required to implement the crawl control and Downhill assist???

if any one here could corroborate or clarify me on this that would be cool.

 

[quhongjun]

All 4WD 4R's have HAC.

It only holds for a few seconds, so you will need either apply the brakes or give it gas to stop it from rolling backward again.

That makes sense. I will do some experiment and report later.:tongue:

 

[BrianLSU]

does it simply measure backward roll of the wheel some how? or does it actually use an accelerometer to measure the vehicle's orientation with respect to gravity??

I would have though that the 4runner has a little mems chip, kind of like the one found in the i-phone or i-touch that measures orientation with respect to gravity (vertical) so that it knows ahead of time that it is about to roll backwards.
Also, this would be a particularly useful sensor to determine the brake settings on the more complex brake modulations used for the crawl control and downhill assist found in the trail and limited.
so basically the SR5 has the same sensors found on the limited and and trail but its just that the SR5 does not have all the suspension hardware required to implement the crawl control and Downhill assist???

if any one here could corroborate or clarify me on this that would be cool.

I think it's a sensor that measures inclination. I was told for an off-road situation that might tilt the vehicle hard, to turn off something, still trying to learn all the buttons, because it will blow the curtain airbags if the vehicle measures 15 degrees off axis.

 

[adio3x]

So when it engages, does it make a clunking sound? Cause I noticed when I was on an inclined hill today, I had my foot on the brakes, let go, rolled back a little, clunk, then somthing popped up on my dash, then tapped on the brakes, then left. Is that it?

 

[Titanpat57]

So when it engages, does it make a clunking sound? Cause I noticed when I was on an inclined hill today, I had my foot on the brakes, let go, rolled back a little, clunk, then somthing popped up on my dash, then tapped on the brakes, then left. Is that it?

Yep..your not a HAC virgin anymore....:bravo:

 

[hoeftm2002]

I think it's a sensor that measures inclination. I was told for an off-road situation that might tilt the vehicle hard, to turn off something, still trying to learn all the buttons, because it will blow the curtain airbags if the vehicle measures 15 degrees off axis.

The feature you are referring to is the RSCA (Roll Sensing Curtain Airbags) OFF button - the sensor measures the angle left to right and deploys the roll over airbags if it thinks the 4runner is about to roll over.

The dealer tells you to push this button to turn these sensors off if you are off road driving so it does not deploy the roll over airbags in error or by accident while you are on a steep sideways slope. The button is on the left side under the mirror adjustment buttons and instrument cluster brightness adjustment control - it is right next to the switch for the power plugs.

 

[iDRiVaT4R]

This is copied from page 254-255 of the owners manual.

If the vehicle is in danger of slipping
or rolling backward when
starting on an incline, or if any of
the drive wheels spins, the slip
indicator flashes to indicate that
the VSC/TRAC (TRC)/hill-start
assist control systems are operating.

A buzzer (intermittent) sounds to
indicate that VSC is operating.
The stop lights and high mounted
stoplight turn on when the hillstart
assist control system is
operating.

Iv'e tested this and it applies the brakes for a little bit then releases again, and keeps that cycle going, I think is assumes by hearing the noises and what not you'll either apply the brakes or hit the gas.

According to this bit of info, if your pressing on the brake pedal though and start rolling backwards, the Hillstart assist will not kick in. Top of page 259 in the owners manual.

Hill-start assist control operation conditions
l The shift lever is in D or S.
l The brake pedal is not depressed.
l The rear differential is unlocked (if equipped).

 

[Go JayBee]

I know this is an old thread, but thought I would chime in here.
I could of swore I read about this here, but could not find the specifics.
I vaguely remember hearing it from a tech person at the dealer when they were training me about the Traction Control, KDDS, etc on the day of delivery.

Almost everyday on my commute, I end up having to stop in traffic on a hill of about a 45 degree slope, uphill.

The only thing I worry about is the car in front of me, so I don't pull up too tight.

Now, what I do is: very firmly hold my right foot on the brake pedal.
When the light turns green and traffic starts moving, I calmly move my right foot over to the gas pedal. In those few seconds, the truck is like glued to the road...no rolling back, no beeps, no crunching sounds.

As I said, you need to depress the brake pedal hard...as if you're trying to drive it through the floor board.

Try it....you'll like it.

Lets hear from [MENTION=68685]Ducmonsta[/MENTION]
I'll bet he has an opinion on this:eyebrows::eyebrows::eyebrows:

 

[1engineer]

Yep. I "stomp" (not really just depress really firm) the break petal (ha I crack me up sometimes) and that makes the assist function work like a charm.