Tonight I noticed that my S60D is making a grinding noise when I turn on summon. I press and hold the roof button on the fob and then press either the frunk or trunk button to summon it. The car makes the usual sounds and then a distinct grinding noise emits for the first few feet. I drove the car at slow speeds with the windows down and couldn't hear any further noise. It APPEARS to only be happening whilst summoning. Thoughts?