Would anyone know what does a buzzing noise (sounds like the one you would hear from a a high-voltage electrical line) means whenever I start my car (a 2001 330ci)? I traced where the sound is coming from, and it seems to be coming from under or near the gas tank and/or near the rear axles. Recently, the "Service Engine Soon" light has been coming on and would stay for several days before disappearing again. I don't know if this has to do with the buzzing sound.
Any insight to this is greatly appreciated!