crf3973

I have a 2016 RX 350 F Sport with the adaptive cruise control. Ive noticed that at lower speeds, specifically in stop and go traffic that the car has a whining sound coming from it. This only happens in stop and go traffic with the adaptive cruise control on.

Any ideas what's going on or if it's normal?

ut2sua

It could be the FSport engine noise generator. Try to turn off Cruise control, then step a bit forcefully on the gas at lower speed. If you hear the same thing, it is the engine noise generator. Your CC is fine if that is the case. Search for "finally a quiet Fsport" in the forum to learn more about the noise generator. Good luck

signdetres

The noise you're experiencing is not related to the sound generator at all.

When you're manually operating the brake pedal, it's silent as the pressure built-up inside the system that sends brake fluid to each of the wheels is generated by you, the driver. When the vehicle is controlling braking on it's own, such as when you're using adaptive cruise control, that pressure needs to build somehow, which is the humming noise you're hearing.

It really should be quite quiet though. The only way you should be able to hear this is at low speeds like you mentioned and either with the audio off or at an extremely low volume setting.

This is normal across Lexus models as well as other makes and models. I've experienced this in RX loaners I've driven, my own GS, and my past Infiniti and Ford. You're good.