ddhleigh

I had this happen to me too. I was already scheduled to have the carbon clean done so the SA told me to drop off the car the day before so they could test it first thing in the morning. The tech said everything was normal and that it happens once in awhile. They said not to worry. My service was about 2 weeks ago. The issue with the hard pedal occurred a few times in the past 2 months.

Fizzboy7

Funny, I had been skipping over this thread for the last few days. Then today, the exact same thing happened to me. So here I am reading up on it.
There still seems to be confusion with some. When all is normal, you step on the pedal and it goes down a little before starting the car. There is some give. But when this problem pops up, the pedal is rock hard and can barely be pushed at all. Those are two entirely different situations, one being normal and the other not. We all know power brakes require the car to be on, but Lexus has designed the system to still be a little soft so we can at least push down to get the ignition going. In fact, all cars have a soft pedal the first time you step on it when the car is off. Only after multiple pumps, does the pedal harden up.
When it happened to me today, I thought my brake line had drained so I got out and checked underneath. Only after standing on the pedal was I able to get the darn thing to turn over. All was fine the rest of the day. I concluded maybe my battery is starting to go. But after reading here, it sounds like a random flaw that pops up from time to time.

evogt500

If your brake line had drained, the pedal would go all the way down to the floor.

vicsis250

You know what I was thinking the same thing my battery might be going out but I tested it with a volt meter and its fine. This is something lexus must know about but is not saying anything.

micel

I started have building pulling tractors and race boats ,both inboard and outboard since around 12 years old,so I might be slightly mechanically inclined.My '06 Is350 has 55k miles on it an I'm having exactly same symptoms.With my 350 it started having sporadic hard pedal about 2 months ago.My take on this is fluid is supposed to be changed at 60k miles.So does the system have a inherit leak in system which would allow oxygen into system?I also changed my pads almost two months ago and brake filler cap (might)was not all the way snapped on for about two weeks.This hard pedal does not seem right and brakes are nothing to fool with.I'm going to change fluid soon and will get back and post results.And please others do same.

ISRocker

iTrader: (1)

This has happened to me several times. I started to keep a log to see if I can spot a trend. Most of the time it happens in the morning. But once in a while, it happens in the middle of the afternoon, even if I am running errands. I try not to press on the brake pedal before I shut off my car, but this still happens. Seems to be occuring about once a month.

mzpretti24

PLEASE PLEASE HELP ME SOMEBODY ANYBODY! I just brought a 2008 is250 about a 6 weeks ago. Love the car. Haven't had any complaints until today. Today I get in the car on my way to work. I go to start the car. Not sure if I pushed the brake too hard, or not at all, whatever the case- the car would not start. Like at all. No lights. No horn. No trunk. The brake will not depress at all. No windows. No power doors. The car just completely shut down. Initially, I thought it must be the battery. So I had my father give me a jump to no avail. The battery is completely charged. I don't know what is wrong with it. I called Lexus Service dept, they told me to try to reset the alarm bc I may have tried to start the car too many times and the alarm system shut the car down. So I did what he suggested. I used the key to manually unlock the car. I tried again to start the car. Still nothing. Like NOT. A. THING. Please help. And of course now the service dept is closed now that I tried what they suggested and it didn't work. I have to go to work tomorrow. I need my car. PLEASE PLEASE PLEASE HELP!!!

FSportIS

iTrader: (13)

You can duplicate the problem here as follow:

Run your car at normal and then turn it off. Now, pump the brake pedal couple times before you move out.
Next time either immediately or tomorrow you turn on your car, you will experience this hard brake pressure.

I think the cause is sometimes after turning off your car, you might have pressed the brake couple times without realizing it before moving out. This might happen 1% of the time and that 1% you did it without knowing it.

FSportIS

iTrader: (13)

Nevermind my previous post, it seems like you need to bring your car to dealership to diagnose.

jsh139

Is the battery in your key fob dead? Try pushing on the brake pedal and hold the key fob against the start button until the light turns green and then push the start button.

tex2670

If the FOB battery was dead, you'd get a "Key Not Detected" when you push the ignition, and the horn and lights would work fine.

OP needs AAA.

Gville350

iTrader: (10)

You have to put ALOT of pressure on that brake pedal my friend! Happended to me twice since April '11. Both times I had to STAND on that brake pedal.

mzpretti24

Okay thanks for everyone's help. I ended up getting the car towed. The ground cable connecting to the battey needed to be replaced. After towing and labor it ended up costing around $400.

Gville350

iTrader: (10)

^Well, good to have your car back I'm sure; but that $400 hit to the wallet kills me for such a minor repair.

Skib

My is completely dead. I tired to replaced a new battery but it still doesn't work. Then I realized the break is not detected and the start button is red not green. Do you have any idea what is going on and what should i do?