Non linear braking issue

Anyone here has issues with braking being non linear on Gen5 (I have a 2018 TRD).

Several times on some near-emergency braking (but close enough), the braking is applied by me in a linear and uniform way, up to a certain point then all of a sudden, the 4runner breaks hard.

Meaning if I apply slow uniform but rapid pressure on the brake pad to get the car to stop in a not-very-abrupt way, the 4runner will slow down, up to a certain point where suddenly it nose dives, stops hard as the output braking is way different and some times the abs will activate.

Not sure if there is a name for this other than than the input braking force on the pedal at a certain point doesn't match the output braking force anymore.

 

Yeah, I have had mine unexpectedly go in to panic braking mode on two occasions over the past 4 years.

it is a characteristic I have seen discussed on forums at least a few times.

 

Yup, happened to me several times…first time it scared the crap out of me!

 

Is there a way to fix this ..it is downright scary ..maybe borderline dangerous.

 

I don't think so, other than modifying our technique. It's the way brake assist is programmed when you go quickly from accelerator to brake pedal.

Toyota's explanation of the system:

Brake Assist (BA)

In emergencies, some drivers, especially inexperienced ones, often panic and do not apply sufficient pressure on the brake pedal. Brake Assist measures the speed and force with which the brake pedal is pushed to determine whether the driver is attempting an emergency stop. If the system determines that is the case, it applies additional brake pressure to allow the driver to take full advantage of the ABS brake system. When the driver intentionally eases up on the brake pedal, the system reduces the amount of assistance it provides. This feature comes with VSC.

 

Interesting, so it's the BA. Thanks for the find.

It is definitely tough to learn when the BA engages. The point where the BA kicks in is so abrupt that it is tough to replicate. I wonder if the BA is computer controlled or just a hydraulic mechanism.

 

My understanding is computer controlled.

 

Does turning off the VSC button also remove the brake assist function.

 

That happened to me a couple of times when I first bought it. Once I got used to the braking system it never happened again.