Hello again.

Second day with my new GS300 and noticed a "pulsing" noise when braking. Haven't had the car for very long and only have about 60 miles. It's not very noticeable when the stereo is at a moderate level. The best I can describe it is it seems like a pulsing sound coming from the engine compartment when braking from over about 30 mph and it seems to slow down as the car slows and the noise seems to stop when you get under about 15-10 mph. Kind of reminds me of the noise when you get something stuck on your tire. The noise isn't that loud and I don't feel any pulsing in the brake pedal like when you engage the ABS. I read through the braking section of the owner's manual and perhaps it has something to do with the Brake Assist feature?

Have any of you come across this or noticed this? I mean, it isn't that annoying, but any sound that I am not used to kind of catches my attention in any car that I drive. Not too worried about it, it's just a noise that my older cars never used to make. But my older cars didn't have all of the technological advances of the GS.

The salesperson called this afternoon just to check in and see how everything was going and I mentioned the braking noise. He said that if I think it's unusual, to come in an a technician will come with me for a test ride. Told him that I was available this afternoon and he said that he will get the service manager and come with me to check it out. So I am going to swing by there after work and see what they say.

Other than that, I am enjoying everything about the car. Slowly learning about all of the features and other things that this car is capable of. Gonna take me a while to get used to not have to take my keys out of my pocket when I approach the car. I also reached forward to turn the key to shut the engine off this morning when I got to work. Don't want to baby the car, but when a semi kicked up some road dust this morning in front of me, I slowed down and changed lanes. Left me with a shallow scratch in the clear coat that looks like a finger nail impression. I would have never even given it a second though with my old 4Runner. But this isn't a 4Runner isn't it?

 

Just got back from the dealership. The salesperson had their service department's lead diagnostic specialist take a road test with me. It was a short road test and I was able to reproduce the sound for him. He noticed it right away on the first attempt at braking from approximately 40 mph. Reproduced the sound again braking from about 35 mph. He stated that the sound was NOT usual for normal braking. However, a third and fourth attempt at trying to reproduce the sound was much softer if at all noticable. He is guessing that it's being caused by some gunk or rust on the rotors. I thought the noise sounded like it was coming from the engine compartment and he thought he noticed it in the right front. At least I had the approximate direction, front.

So I have an appointment to have them do a thorough evaluation. Hopefully this is just a minor bump in the road and it is easily fixed. Otherwise I am really enjoying the car!

 

After being in the shop for 5 days, they informed me that my car is ready to be picked up. The problem with the rotors are that they are warped (due to something about shimming of the front brake pads) and that they have ordered replacement rotors for them as per a TSB issued regarding the front brakes of the 3GS. I searched the link on alldata.com and couldn't locate one. One the replacement parts come in, they are going to replace the front rotors and the brake pads. I hope that will completely solve the problem. But now I have at least a couple of weeks before this problem is resolved.

Seems like a pretty big "replacement part" for a vehicle that I've had for less than three weeks. And I noticed the pulsing noise on the first day (with 12 miles or so on it). Doesn't quite add up to me, but I am not a Lexus tech. Will see what they have to say when I go down to pick up my car.

Added - Regarding the rust that I noticed on the surface of the rotors. They explained that the tech stated that a certain amount of rust is to be expected on the rotors. But I think that they didn't even clean it in the prep phase as I've only had my car for two and a half weeks. My dads Land Cruiser is over a year old and his rotors look pretty clean to me. I mean I seem some rust spots developing, but not like the way my GS looks. Will talk to the salesperson about this when I pick up my car.

 

Talked with the service consultant yesterday and he said that the technician had called Lexus support and they said that if the rotors are found to be slightly outside of tolerance, just to replace both the rotors and the brake pads, which is what they are going to do. So there is no TSB for the brakes as previously indicated.

The notes from the tech states that he verified my complaint about the pulsing brakes and that the front rotor thickness variation is listed as excessive 0.06mm. I thought it was just some rust that they needed to clean off the rotors from when a tech did the first road test with me. Replacing the rotors seems quite drastic and a variation of 0.06mm doesn't seem that bad to me, but I know next to nothing about what is a "normal" tolerance. Does it sound like they just don't know what is causing the brake pulsing noise and are punting and just replacing the rotors? I don't want to start second guessing Lexus service, but does this sound a little odd to anyone?