I have an 01 cls when i start the car and then begin to move the car makes about a 2 second low humming noise (kinda sounds like a bumble bee lol). Sometimes it does it twice but its only when i first start it. Idk what it is

 

lol i asked the same question when i got my car, now i barely notice it cause it's expected. I believe it only happens when things are cold est in the morning. it's actually the abs system doing it's pre-check before driving basically. so u got nothing to worry about, cause all is working well.

my car does the same thing. sall good

 

Yep, ABS system, normal.

 

Awesome thanks guys