My car has recently started making a squeal noise while driving that actually goes away when I apply the brakes. What could be wrong?
Most likely your brake pads are worn sufficiently enough to allow their "wear indicators" or "sensor" to touch the disc brake rotor. When this occurs the "sensor" emits that high pitch noise designed to warn you that your brakes need immediate attention. Have them checked promptly by a certified brake system specialist and have the brakes serviced before expensive damage or loss of brakes occurs.