DriverDan

i have a new GX460. when i am on a hill stopped i take my foot off of the brake and push the gas. the suv goes crazy with blinking lights and makes the noise of the anti lock brakes for a very long time. during this time the suv rolls backward.

is this happening to any one else?

Koz

The hill start assist kicked in. It helps keep the vehicle from rolling back.

Koz

DriverDan

actually, it is called the brake assist. it is not "kicking in". it is going heywire and when i hit the gas nothing happens i just roll backwards. i actually have to stomp on the brake and put the vehicle in park then back to drive to get the accelerator to work and make the suv go forward. it will roll backwards until i hit the brake even going back 30 feet for 5 or 10 seconds.

i just got it back from the dealer and they can not figure it ou.

Koz

It is not brake assist (different system). Brake assist applies braking when in a panic stop and you inadvertently release full brake pressure (the computer applies full brake pressure). Hill start assist will pulse the brakes to HELP (notice the word help) keep the vehicle from rolling back. What you are experiencing is normal. The system does not lock the brakes and stop the vehicle. If it did, you could slid and lose control of the vehicle (not good when off roading on a slippery hill). As long as you are moving back the system will be going crazy, with all kinds of sounds, lights flashing and brakes pulsing.

Koz

DriverDan

sorry, koz. it's brake assist. they just brought in lexus regional and corporate folks to diagnose. it was not the hill start assist that is malfunctioning. it is the brake assist. and they can't figure out why but they believe it is a one time software thing. nothing shows on the computer.

akfd

I guess you're the only person in this forum that's got a major software issue with their GX. The Hill Assist DOES work, albeit a little freaky with all the weird noises and flashing signals, but it does an adequate job of preventing the truck from rolling backwards uncontrollably. Since the Lexus mechanics concluded that it was indeed the Brake Assist System kicking in when it isn't supposed to, I think that's considered a pretty BIG software glitch for Lexus/Toyota!

Koz

If the hill start assist was engaged and you jabbed the brakes, the brake assist could have also kicked in and may have caused all the confusion. I've had these systems for many years and they work VERY well, but they can do some strange things when more then one are working at one time. This is where VDIM sorts it out and prioritizes each system.

Koz

bababooey9

I have the same exact problem that Dan has. I am dropping it at the dealership tomorrow night. I will keep you posted once I get the results from the dealer. I dont want to speculate right now what I think the problem is but it definitely does not sound like the Brake and/or Hill Assist (whichever it is) is working properly. My car makes a loud clicking noise when I am trying to accelerate from a stopped position on a hill. This is not the first issue I have had with this vehicle.

spwolf

thats hill assist working properly :-).

when you are on incline, brakes apply and when you hit gas, they get released which makes clicking noise, just like ABS.

spwolf

if nothing shows on computer and they cant reproduce it, they didnt diagnose anything.

DriverDan

i am wondering if anyone else (bababooey?) has had this happen again or yet. they just took my suv in for the 4th time.

those of you who say it is "working" and that's the way it "works" need to read the posts again. no suv should roll backwards 20 feet down a hill when in drive when you hit the gas. the way it is sopposed to work is for it to ease you in to drive maybe going backwards a small bit. i now had to put it in park then back to drive to get it to go uphill.

Koz

The hill start assist will not stop the vehicle from rolling backwards (slows it); what it does is help keep the vehicle from sliding out of control, backwards. This would happen If it locked the wheels on a slippery surface. You should be able to hit the gas (having traction) and the system should stop.

Maybe there is something going on with the new brake over ride system and the hill start.

Koz

DriverDan

i think we all get what it is supposed to do koz. again, hitting the gas does not stop it from rolling backwards. i am on here today again because the same thing happened on level ground as i pulled up to my driveway. the curb is about 5 inches above the road. I pulled up to it and stopped with my front tire against the curb at the bottom of my driveway. I reached out to get my paper, then took my foot off of the brake and pushed the gas. nothing. click click click. i am going to insist on my money back. it looks like it is starting to happen to other people too. my dealer had someone else bring it back.