mswilsonuk

The annoying buzzing from the brake booster check valve that comes from the left of the instrument panel when lighly braking (especially when parked or waiting at a traffic light) is a well-known problem, as it was the subject of a Lexus (and Toyota) TSB for 2004-2010 models(see link below to the clublexus link), and has been discussed on many forums for Lexus and other cars.

I just bought a new 2012 RX 350 last month, and within a week it started making this buzzing noise (left instrument panel upon light braking). I took the car to the dealer and without listening they said that they knew it was the brake booster valve (the noise is the rattling of a ball bearing when the valve is malfunctioning). They replaced the valve and the noise went away (the loaner RX they gave me made the noise even worse).

Well, 3 weeks later, the noise has returned!

(1) Am I the only one having this problem with their new Lexus? These cars are everywhere, I can't imaginge that I am.
(2) Can it be fixed permanently?
(3) Why is this still happening on 2012 models? Can't they solve this damn problem?This is an expensive car and should not have this issue.

Many thanks!

Link to TSB posted on clublexus (sorry, it is so long!)
http://www.google.com/url?sa=t&rct=j...lbbFKYoZKN--7Q


sample of other discussion
http://us.lexusownersclub.com/forums...howtopic=44668

mswilsonuk

56 views? I guess That I must be the only unlucky person to have this problem? Or no one cares about it?

Cruiter

Bob
Your post is the 1st I've heard of it. I'd get comfy with your service manager.

mswilsonuk

Thanks Cruiter, well I hope that means it is fixable then. The problem is worse when it is cold outside (near or sub freezing).

The TSB (L-SB-0074-09) for this is linked somewhere here on the clublexus forum. Similar TSBs were also released for Toyota
2005 – 2010 Avalon
2007 – 2010 Camry
2008 – 2009 Highlander
2006 – 2009 RAV4
2004 – 2010 Sienna

Quote from TSB " Some RX 330/350 vehicles may exhibit a rattle or buzz type noise coming from the driver’s side instrument panel area. The noise can be duplicated when lightly accelerating and then decelerating, or when depressing the brake pedal with the shift lever in Park and then releasing the brake pedal. An improved vacuum check valve is now available to reduce this noise.

1. Confirm the noise is coming from the brake booster vacuum check valve.

2. Replace Valve

This TSB is for 2004-2010 models. I am surpized that I am getting this problem still on my new 2012.

alexmeller

Curiously (or frustratingly enough) my new 2015 RX350 has this very rattle. Fairly subtle - you can only hear it when idling or driving in a parking lot, but noticeable. First visit to the dealer they could not hear it. I am making another attempt and will try to explain to them that the culprit is known - thanks to this forum.

It really is amazing that the problem Lexus was aware of in 2009 is still present in 2015!

Marqevans

I have it on my 2012 also, but I never remember to mention it. I think I had it on my 2010.

alexmeller

How loud is your rattle? Is it the same in your 2012 as it was on 2010? In my case, there is a noticeable rattle when I rear from my garage while holding brakes and shortly after. When I drive forward I can only hear it on the traffic lights if I pay attention and radio is off

Marqevans

I have ignored for so long. It is not very loud. It's definitely brake related and kind of sounds like an "air whisper" with a slight rattle.

alexmeller

I had the valve replaced by the dealer this morning. They did not believe that this would help the rattle but did it as an exception per my request and with no guarantees.
The part number installed is 44730-60070. (My vehicle is 2015 RX350, but I am sure the same part will fit previous year models).

So far it seems to have helped and the rattle is gone. I will have to keep watching (or listening) for a couple more days to see if weather has any impact.

Gribble

alexmeller
please update us on the noise. I have a 2013 and have the same rattle/vibration sound as you described.

alexmeller

3 days of testing - no noise/rattle. Replacing the valve took care of it. In case you cannot convince the dealer to replace it under the warranty, the part is only $30 and takes 10 min to replace

Gribble

does anyone know how to replace this brake booster valve? Also the part number listed above isn't showing up on Lexus Sewell site.

alexmeller

The part number is correct - it is the latest. I am sure the older part available at Sewell would be ok as well. I don't think they are that much different. It is just the matter of luck to get a bad one on your car.
As for the replacement, I was not allowed to watch the replacement, but I know that a mechanic (a smaller guy with thin hands) was able to pull it out and push a new one in without disassembling anything (except for plastic engine covers). Yet, I would not do it myself.

Gribble

I just ordered the part, thinking of trying to install myself.
Alexmeller, are you still rattle free after having the part installed?

adgvpm

I have a 2014 RX350, and around the 500 mile mark I began hearing a faint static/buzzing noise that is definitely noticeable when it is very cold outside. It seems to be related to the braking system (i.e. when you press and release the brake pedal), but I have heard it when I'm just driving and not touching the brake pedal. It almost sounds like the car's electronics are going through a self-check, but it is audible. Took my RX to the dealer and they said that the noise is "normal" and that all third generation RX's have that noise - something to do with the brake pedal modulation? All I know is that it is annoying, especially when everything else is so quiet when you drive without the radio on and the fan speed turned down. I've driven other 2014s RXs at the dealership and also heard the noise. My dealer has not offered to replace any parts. Definitely disappointing in any car but especially a Lexus. I would be very interested to know if anyone who had this problem and then had the brake booster valve replaced if that solved the issue.