I know if I press and depress the brake pedal several times (releasing vacuum?) while the engine is not running, the brake pedal will become hard. And I assume if I park a car for long time, the vacuum will be gone and the brake pedal will become hard as well. I can park my other vehicles for a week and do not experience the hard brake pedal. But, if I don't drive my 2017 RX 350 for 3 days, the brake pedal will be hard. Is that normal?

 

Check out this thread.

https://www.clublexus.com/forums/rx-...-starting.html

 

I have not seen the error message yet, just hard brake pedal. But I bet it is the same issue. It is leaking somewhere.

 

They can fix at your next service!

 

Yes! So far, I have a leaking sunroof (fixed), rattle front doors, some excessive noise and vibration, rough shift on certain conditions, and now brake line leaking. Basically anything posted here, I would have them Definitely not the experience I expected from Lexus.

 

Just hard to imagine how your vehicle could have so many problems and both of my 450h units have been without flaw. Only thin extra I told them at service was 5 blinks instead of three and kill the S-Flow cr^p.

 

Both of yours is a tiny sample size in the grand scheme of things. 500 could be great and one could be a lemon - happens all the time.

 

450h has a different engine and transmission. And since it is hybrid, I guess the brake is not the same either. So more than half of my issues will not even happen on your vehicles. I saw the leaking from microphone hole thread right after I bought my RX. I thought I was lucky till one day I saw the water dripping from there.

BTW, as I said in another thread, I am fine with the S-Flow feature But sometimes it is hard to tell its logic. This morning, when I drove my RX to work, with no passenger, I noticed the S-Flow was off. I had to turn it on manually.

 

You could have a defective brake booster pump. It's hard to imagine it fails for new car. I had that hard brake problem on my 1997 Lexus LX450 after 150,000 miles.

 

I also get a hard brake pedal if I don't drive my RX350 for two-three days. But it starts right away and the brake pedal goes back to normal so it's no big deal to me. I don't get any error codes however.

 

Same here. I am just afraid there is a leak and it may become worse.

 

Same here. Defective parts/design

 

I think this is normal - I experience this on my other car but not the RX yet.

 

Well, did my 5k miles service today. I was told the brake is normal. The service advisor even brought up the error code thing himself.

They did fix the rattle problem without even opening the door panel.

 

My two month old RX sits in the garage for 2-3 days or so and yes, it has a hard pedal until it starts. I doubt this is a problem, but then again this is my first "keyless" car, so I never had to step on the brake to start it.