Why is my car making a squeaking sound

I have a jag and had the same problem. First lift your car front end up and check your rotors and shake the wheel and rotors to make sure everythings tight if rotor shakes you need wheel bearings if rotor has deep scares and not smooth surface i recommened new pads, rotor, with caliper. If car is parked and you put your foot on gas pedal lightly and you here squeak check into replacing belt tensioner assembley along with belt should quiet your jag!!!