RXSF

This has happened to me multiple times now and its actually quite dangerous. Of course, this problem is exacerbated by all the hills around me.

Today when parked on the hill, I started the car and of course it takes about 10 seconds for the gas engine to start. Well before the ICE kicked in, I was already reversing out of my spot with foot on the brake. I noticed the pedal was rock hard and I could barely stop the car in time from hitting the one behind me.

I had to pause, and wait for the ICE to kick in so that the brakes would be power assisted. Be careful out there if you have step on your brakes when engine is off, you will not have power brakes until the ICE starts also.

lucasb7

The brake booster is driven by an electric motor in all recent Toyota/Lexus hybrids. You should be able to faintly hear it turn on when you open the driver's door. Whether or not your can hear it, I would take your car to the dealer and talk to them about this, the booster may be going bad.

Droid13

I agree, this is not a normal situation at all.

wa3cuj

This has happened to me also. I found that it happens if I shift into reverse before all of the lights on the dash that light at startup, go out. I have learned to wait a few seconds and then shift to reverse. ICE has not started yet when I do this also.

Cruiter

The power assist on your brakes is electric. It doesn't depend on the ICE. It sounds like you pressed hard enough on the gas pedal for the hill parking break (anti-roll back) feature to kick in. Going to the throttle automatically releases that.

RXSF

No, I dont think the HSA has anything to do with this since I was moving. I am sure it has to do with ICE and booster because it has happened to me multiple times and with the ready light on.

The situation always happens on a hill and if you want to test it you can. Try this:

turn off the car but pump the brakes 2 times leaving your foot on the brake on the second pump. Only do this on a warmed up engine so that the ICE doesnt kick in instantly when you push the start button. Then start the car and try to stop the vehicle either in reverse or drive.

Only until I wait for the ICE to start does the brake pedal become soft again

jmhenrie

tried to follow your directions to create this problem, i could not recreate it, me thinks something is wrong with your system.
cheers
Mike

Cruiter

Josh, I'm not trying to beat a dead horse here, just explaining a factor in the hybrid braking system. They are total electric in the control of them, they have to be to function when the ICE is off (which is often). Like the throttle, they are drive by wire. That said there is a hydraulic side to them for when heavier braking is needed but it's also supplied by an electric pump (for when the ICE is off). If you pull the panels off the engine bay of your (h), you'll have a hard time finding a belt that turns anything.

RXSF

Im not disagreeing that the booster is electric, but Im saying the booster, perhaps in my car only or in certain situations, is not providing power assistance.

surprised to hear that it cannot be duplicated in Mike's car. Any other takers?

Cruiter

Use your warranty then update us as to what they said please.

Droid13

I couldn't duplicate the issue either after a couple of separate attempts. The second time I just tried continuing to pump the brake pedal with the car off to see if I could get the pedal hard. Every third press of the brake pedal I could hear the electric booster come on and the pedal continued with power assist. I did have the key with me though. Lucas mentioned that when you open the door the brakes will prime. I believe its actually a combination of opening the door and having the key with you.

As far as I can tell, at least if you have the key with you, the power brakes stay primed all the time even if the power switch is off.

RXSF

actually now that you mention it, my door was opened briefly. Is it possible for you to try it by turning the car off, then open your door, then pump the brakes?

Droid13

Still no difference with door open. Both with and without the key on me, the brakes continue to prime about every 3rd press on the pedal.

cossie1600

I live on a steep hill. I never warm up my car or wait for the lexus enform screen to go out before I drive, never had a problem with the brakes. There were occasions where I wouldn't get power steering

RXSF

Okay, I tried it on flat road and I dont get the same result. Perhaps it is a hill thing. will investigate further.