Hill Problems :'(

[flashbolt]

Today I was stopped at a red light on a really steep hill. When it turned green and I let off the brake it started rolling backwards. I hit the gas pretty fast and I heard this rumbling/almost grinding sound and the VSC light a buzzer starting coming on. Once I got moving forward it was fine, but this scared the crap out of me.

I have an 06 T4R sport with 30K mi on it. What is wrong with my baby :'(

 

[K.C.]

I get the same thing.

Steep hill plus low tread on the tires.

Nothing to worry about, as long as you swap out the tires.

 

[Thai]

Today I was stopped at a red light on a really steep hill. When it turned green and I let off the brake it started rolling backwards. I hit the gas pretty fast and I heard this rumbling/almost grinding sound and the VSC light a buzzer starting coming on. Once I got moving forward it was fine, but this scared the crap out of me.

I have an 06 T4R sport with 30K mi on it. What is wrong with my baby :'(

It is either your HAC helping you out by preventing your 4runner from rolling backwards or it is your ATRAC working.

Either way, you are OK.

 

[flashbolt]

Re: Re: Hill Problems :'(

It is either your HAC helping you out by preventing your 4runner from rolling backwards or it is your ATRAC working.

Either way, you are OK.

IDK what either of those things are but thank you so much. I was really worried there for a minute.

 

[Evil Sofa Leg]

It caught me off guard the first time it happened too...

I wasn't expecting it to be so loud considering how quiet the vehicle is (overall) but its a neat feature...

 

[Thai]

Re: Re: Re: Hill Problems :'(

IDK what either of those things are but thank you so much. I was really worried there for a minute.

HAC = hill assist control

--> When the computer senses that the car is rolling backwards (like in your situation), the ABS (anti-lock brake system) will pulsate the brakes to either slow down your 4runner from rolling backwards or to keep you stationary (depending on hill grade) while you make the transition from brake pedal to gas pedal. A cool technology.


A-TRAC = 4-wheel traction control system (if you have 4wd)

or

Auto-LSD = 2-wheel traction control system on the rear axle (if you have 2wd)

--> Traction control systems will brake a spinning/slipping wheel(s) so that your 4runner can regain traction and move forward. It works by comparing speed differences between two tires on the SAME axle. If one tire is spinning too fast relative to the other tire (on the same axle), then the ABS computer will pulsate the brake caliper on the spinning wheel to slow it down because the computer is assuming that the tire that is spinning fast is the one that is slipping on snow (= no traction). This allows the transfer of power/torque to the tire that is not spinning, which is usually the tire with traction. In other words, by pulsating the brakes on the spinning/slipping tire, you allow power to flow to the other tire that is not slipping.

Hope this helps.