Ling_Joseph

I have a 2008 RX350 made in Canada. The only thing I don't like it that it makes low buzzing sound when pressing or releasing the brake. It is more noticable when driving slowly with the music off.

I used a scope and found the noise to be coming from the brake booster check valve. The dealer agrees and will order one. I put some Dynamat on the Brake booster and the check valve. The noise is gone!!!!!! :) I am happy now!

My dealer has replaced my brake booster check valve, but it didn't solve the problem. It's great to know it can be fixed using the Dynamat. I wonder if Lexus can do it for free if they don't have better solutions.

Thanks for the update. The buzzing on my car seems like a little lower in rainy days, but louder when the whether is dry and cold. Since there are still many other people think their RX350 is perfect, maybe there is a high chance of solving the problem by replacing brake booster.

Looking forward to see your good news on fixing the buzzing noise.

How about the buzzing you mentioned earlier? My RX 2008 also have buzzing noise when pressing and releasing the brake pedal, also sometimes when releasing the gas pedal when driving slowly. Dealer replaced the Brake booster check valve, but it didn't solve the problem.

2009 models?

No, mine 2008 module

I reserached a little more around the net, and found several other are having the same issue. Some were 2009 models. I guy claims it is the Brake booster check valve not a relay. I will post when ny car returns from service.

Yes, it is more like a buzzing than hissing. I did take it to dealer and they also said it was the brake booster check valve, and they ordered the part and replaced it on my car. But it didn't make any difference. So I took the car back to the same dealer, and they verified the noise still exist, and said it is necessary to replace the entire brake booster, and let me use their rental car for a day while they work on it. But later they called me saying they called Lexus and they were told it is a known issue, replacing brake booster won't solve the problem, and there is no fix at the time.

By the way, the rental car they let me drive was a RX350 2007, I notice the same problem on the rental car. The buzzing does bother me, especially when I think of the price I paid for it.

Could you share the link that you found around the net if you still remember it?

I recently bought a 2008 RX350. From day one I noticed small hissing noise when I gentally press the brake all the way down and then release it slowly. The same noise sometimes can be heard when I dirve slowly and release the gas pedal. Anyone had the same problem? Is there a fix? Thank!